Search

The availability of large state and federally run administrative health-care databases provides potentially comprehensive population-wide information that can dramatically impact both medical and health-policy decision-making. Specific opportunities and important limitations exist with all administrative databases based on what information is collected and how reliably specific data elements are reported. Access to patient identifiable-level information can be critical for certain long-term outcome studies but can be difficult (although not impossible) due to patient privacy protections, while more easily available de-identified information can provide important insights that may be more than sufficient for some short-term operative or in-hospital outcome questions. The first section of this paper by Sarah K. Meier and Benjamin D. Pollock discusses Medicare and the different data files available to health-care researchers. They describe what is and is not generally available from even the most granular Medicare Standard Analytic Files, and provide an analysis of the strengths and weaknesses of Medicare administrative data as well as the resulting best and inappropriate uses of these data. In the second section, the Nationwide Inpatient Sample and complementary State Inpatient Database programs are reviewed by Steven M. Kurtz and Edmund Lau, with insights into the origins of these programs, the data elements that are recorded relating to the operative procedure and hospital stay, and examples of the types of studies that optimally utilize these data sources. They also detail the limitations of these databases and identify studies that they are not well-suited for, especially those involving linkage or longitudinal studies over time. Both sections provide useful guidance on the best uses and pitfalls related to these important large representative national administrative data sources.

Background Patent foramen ovale (PFO)‐associated platypnea‐orthodeoxia syndrome is characterized by dyspnea and hypoxemia when upright. The pathogenesis is thought to involve an increase in right atrial pressure or change in degree of right to left shunting with upright posture. Methods and Results We sought to characterize patients with platypnea‐orthodeoxia syndrome related to PFO without pulmonary hypertension. We retrospectively reviewed databases at 3 tertiary referral hospitals in New South Wales, Australia from 2000 to 2019. Fourteen patients with a mean age of 69±14 years had a PFO with wide tunnel separation. Mean New York Heart Association Classification was II (±0.9) and 7 inpatients had been confined to bed (from postural symptoms). Baseline oxygen saturations supine were 93%±5% and 84%±6% upright. Two patients had a minor congenital heart defect and 4 had mild parenchymal lung disease with preserved lung function. The mean aortic root diameter was 37±6 mm and distance between aortic root and posterior atrial wall was 16±2 mm. Platypnea‐orthodeoxia syndrome was preceded by surgery in 5 patients and 1 patient had mild pneumonia. Successful closure of the PFO using an Amplatzer device was performed in 11 of 14 patients. Post‐closure, all patients had New York Heart Association Classification I (improvement 1.6±0.9, P P Conclusions Platypnea‐orthodeoxia syndrome is a debilitating condition, curable by PFO closure. Anatomical distortion of the atrial septum related to a dilated aortic root or shortening of the distance between the aortic root and posterior atrial wall may contribute to the syndrome.

Background Future projections for both TKA and THA in the United States and other countries forecast a further increase of already high numbers of joint replacements. The consensus is that in industrialized countries, this increase is driven by demographic changes with more elderly people being less willing to accept activity limitations. Unlike the United States, Germany and many other countries face a population decline driven by low fertility rates, longer life expectancy, and immigration rates that cannot compensate for population aging. Many developing countries are likely to follow that example in the short or medium term amid global aging. Due to growing healthcare expenditures in a declining and aging population with a smaller available work force, reliable predictions of procedure volume by age groups are requisite for health and fiscal policy makers to maintain high standards in arthroplasty for the future population.Questions/purposes (1) By how much is the usage of primary TKA and THA in Germany expected to increase from 2016 through 2040? (2) How is arthroplasty usage in Germany expected to vary as a function of patient age during this time span? Methods The annual number of primary TKAs and THAs were calculated based on population projections and estimates of future healthcare expenditures as a percent of the gross domestic product (GDP) in Germany. For this purpose, a Poisson regression analysis using age, gender, state, healthcare expenditure, and calendar year as covariates was performed. The dependent variable was the historical number of primary TKAs and THAs performed as compiled by the German federal office of statistics for the years 2005 through 2016. Results Through 2040, the incidence rate for both TKA and THA will continue to increase annually. For TKA, the incidence rate is expected to increase from 245 TKAs per 100,000 inhabitants to 379 (297-484) (55%, 95% CI 21 to 98). The incidence rate of THAs is anticipated to increase from 338 to 437 (357-535) per 100,000 inhabitants (29% [95% CI 6 to 58]) between 2016 and 2040. The total number of TKAs is expected to increase by 45% (95% CI 14 to 8), from 168,772 procedures in 2016 to 244,714 (95% CI 191,920 to 312,551) in 2040. During the same period, the number of primary THAs is expected to increase by 23% (95% CI 0 to 50), from 229,726 to 282,034 (95% CI 230,473 to 345,228). Through 2040, the greatest increase in TKAs is predicted to occur in patients aged 40 to 69 years (40- to 49-year-old patients: 269% (95% CI 179 to 390); 50- to 59-year-old patients: 94% (95% CI 48 to 141); 60- to 69-year-old patients: 43% (95% CI 13 to 82). The largest increase in THAs is expected in the elderly (80- to 89-year-old patients (71% [95% CI 40 to 110]). Conclusions Although the total number of TKAs and THAs is projected to increase in Germany between now and 2040, the increase will be smaller than that previously forecast for the United States, due in large part to the German population decreasing over that time, while the American population increases. Much of the projected increase in Germany will be from the use of TKA in younger patients and from the use of THA in elderly patients. Knowledge of these trends may help planning by surgeons, hospitals, stakeholders, and policy makers in countries similar to Germany, where high incidence rates of arthroplasty, aging populations, and overall decreasing populations are present. Level of evidence Level III, economic and decision analysis.

The Affordable Care Act of 2010 advanced the economic model of bundled payments for total joint arthroplasty (TJA), in which hospitals will be financially responsible for readmissions, typically at 90 days after surgery. However, little is known about the financial burden of readmissions and what patient, clinical, and hospital factors drive readmission costs. (1) What is the incidence, payer mix, and demographics of THA and TKA readmissions in the United States? (2) What patient, clinical, and hospital factors are associated with the cost of 30- and 90-day readmissions after primary THA and TKA? (3) Are there any differences in the economic burden of THA and TKA readmissions between payers? (4) What types of THA and TKA readmissions are most costly to the US hospital system? The recently developed Nationwide Readmissions Database from the Healthcare Cost and Utilization Project (2006 hospitals from 21 states) was used to identify 719,394 primary TJAs and 62,493 90-day readmissions in the first 9 months of 2013 based on International Classification of Diseases, 9th Revision, Clinical Modification codes. We classified the reasons for readmissions as either procedure- or medical-related. Cost-to-charge ratios supplied with the Nationwide Readmissions Database were used to compute the individual per-patient cost of 90-day readmissions as a continuous variable in separate general linear models for THA and TKA. Payer, patient, clinical, and hospital factors were treated as covariates. We estimated the national burden of readmissions by payer and by the reason for readmission. The national rates of 30- and 90-day readmissions after THA were 4% (95% confidence interval [CI], 4.2%–4.5%) and 8% (95% CI, 7.5%–8.1%), respectively. The national rates of 30- and 90-day readmissions after primary TKA were 4% (95% CI, 3.8%–4.0%) and 7% (95% CI, 6.8%–7.2%), respectively. The five most important variables responsible for the cost of 90-day THA readmissions (in rank order, based on the Type III F-statistic, p

As life expectancy increases, more elderly patients with end-stage hip arthritis are electing to undergo primary THA. Octogenarians undergoing THA have more comorbidities than younger patients, but this is not reflected in risk adjustment models for bundled care programs. The burden of care associated with THA in octogenarians has not been well characterized, and doing so may help these value-based programs make adjustments so that this vulnerable patient population does not risk losing access under accountable care models.The purpose of this study was to describe care use, comorbidities, and complications among octogenarians undergoing primary THA.Five percent of the Medicare national administrative claims data was queried to identify patients diagnosed with hip osteoarthritis between January 1, 1998, and December 31, 2013. Patients who underwent primary THA were identified and followed longitudinally during the study period using their unique, encrypted Medicare beneficiary identifiers. We compared risk factors and complications between the octogenarian group versus those aged 65 to 69 years. Multivariate Cox regression was used to evaluate the effect of patient/hospital factors on risk of revision, periprosthetic joint infection, dislocation, venous thromboembolism (VTE), and mortality. Patient factors in the model included age, sex, race, region, socioeconomic status, and health status based on Charlson comorbidity score 12 months before replacement surgery.There were 11,960 THAs in the octogenarians in 1998, which increased to 21,620 in 2013, an 81% increase during this study period. Octogenarians were more likely to have a Charlson score of 3 or higher than those patients aged 65 to 69 years (30% versus 17%, odds ratio [OR] 2.07 [1.98-2.20]; p0.001), and they were more likely to have coronary artery disease or congestive heart failure (47% versus 29%, OR 2.16 [2.06-2.26]; p0.001). The octogenarian group had a greater risk of dislocation (+12%, p = 0.01), VTE (+14%, p0.001), and mortality (+150%, p0.001) compared with the younger age cohort. A total of 21% of the octogenarians were readmitted after surgery compared with 12% for patients in the younger group (OR=1.64, 95% confidence interval 1.54-1.75; p0.001).Because octogenarians are at increased risk of dislocation, VTE, medical complications, and mortality after THA, value-based care models that penalize hospitals for readmissions and complications may inadvertently result in loss of access to care for this group of patients as a result of the financial makeup of these bundled care models. Value-based care models were developed to improve care and decrease healthcare costs but may have unintended consequences in the octogenarian with higher complication and readmission risks. Financial losses may lead to institutions from withdrawing from the Bundled Payments for Care Improvement program. To try to prevent this from happening to this vulnerable patient population, bundled care programs should evolve and be modified to allow for risk stratification in the overall payment formula to account for increased age and comorbid conditions to ensure continued successful participation in the program among all the stakeholders.Level III, therapeutic study.

Patients with morbid obesity, defined as a BMI greater than 40 kg/mWe sought to quantify (1) the surgical risk, and (2) the costs associated with complications after THA in patients who were morbidly obesity (BMI ≥ 40 kg/mThis is a retrospective study of patients, using Medicare hospital claims data, who underwent THA. The ICD-9 Clinical Modification (CM) diagnosis code V85.4x was used to identify patients with morbid obesity and with super obesity from October 1, 2010 through December 31, 2014. Patients without any BMI-related diagnosis codes were used as the control group. Twelve complications occurring during the 90 days after THA were analyzed using multivariate Cox models adjusting for patient demographic, comorbidities, and institutional factors. In addition, hospital charges and payments were compared from primary surgery through the subsequent 90 days.Patients with morbid obesity had increased postoperative complications including prosthetic joint infection (hazard ratio [HR], 3.71; 95% CI, 3.2-4.31; p0.001), revision (HR, 1.91; 95% CI, 1.69-2.16; p0.001), and wound dehiscence (HR, 3.91; 95% CI, 3.14-4.86; p0.001). In addition, patients with morbid obesity had increased risk of deep vein thrombosis (HR, 1.43; 95% CI, 1.14-1.79; p0.002), pulmonary embolism (HR, 1.57; 95% CI, 1.25-1.99; p0.001), implant failure (HR, 1.48; 95% CI, 1.3-1.68; p0.001), acute renal failure (HR, 1.68; 95% CI, 1.56-1.80; p0.001), and all-cause readmission (HR, 1.48; 95% CI, 1.40-1.56; p0.001). However, death (HR, 0.94 95% CI, 0.73-1.19 p0.592), acute myocardial infarction (HR, 0.94; 95% CI, 0.74-1.2 p0.631), and dislocation (HR 1.07; 95% CI, 0.85-1.34; p0.585) were not different between patients in the control and morbidly obese groups. Super obese patients had an increased risk of infection (HR, 6.48; 95% CI, 4.54-9.25; p0.001), wound dehiscence (HR, 9.81; 95% CI, 6.31-15.24; p0.001), and readmission (HR, 2.16; 95% CI, 1.84-2.54; p0.001) compared with patients with normal BMI. Controlling for patient and institutional factors, each THA had mean total hospital charges of USD 88,419 among patients who were super obese compared with USD 73,827 for the control group, a difference of USD 14,591. Medicare payment for the patients who were super obese also was higher, but only by USD 3631.Patients who are super obese are at increased risk for serious complications compared with patients with morbid obesity, whose risks are elevated relative to patients whose BMI is less than 40 kg/mLevel III, therapeutic study.

Advances in surgical technique, implant design, and clinical care pathways have resulted in higher expectations for improved clinical outcomes after primary THA; however, despite these advances, it is unclear whether the risk of revision THA actually has decreased with time. Understanding trends in short- and mid-term risks of revision will be helpful in directing clinical, research, and policy efforts to improve THA outcomes. We therefore asked (1) whether there have been changes in overall short- and mid-term risks of revision THA among patients in the Medicare population who underwent primary THA between 1998 and 2010; and (2) whether there are different demographic factors associated with short- and mid- term risks of revision THA. Using the Medicare 5% national sample database, patients who underwent primary THA between 1998 and 2010 followed by subsequent revision through 2011 were identified by ICD-9-CM procedure codes 81.51 and 81.53/80.05/00.70–00.73, respectively. This dataset included a random sample of Medicare beneficiaries based on their social security number. Only patients with minimum 1-year followup after primary THA were included in our analysis. A total of 64,260 patients who underwent primary THA were identified from the 1998 to 2010 Medicare 5% dataset. Eighty-eight percent of the patients had 1-year followup providing a final study cohort of 56,700 patients. The risk of revision was evaluated at 1, 3, 5, and 7 years. Multivariate Cox regression was used to evaluate temporal trends in revision risk using two methods to account for time effects with periods 1998 to 2002, 2003 to 2007, and 2008 to 2010 for the index year of primary THA, and individual year of index of primary THA as independent variables. The analysis adjusted for patient age, sex, race, census region, Charlson score, and socioeconomic status. The 7-year crude risk of revision THA declined from 7.10% in 1998 to 2002 to 6.09% in 2008 to 2010, representing a 14.4% overall reduction in adjusted risk of revision (p = 0.0058; 95% CI, 4.4%–23%). Similarly, the 5-year crude risk of revision THA declined from 5.96% in 1998 to 2002 to 5.11% in 2008 to 2010, representing a 14.2% overall reduction in adjusted risk of revision (p = 0.0069; 95% CI, 4.1%–23%). However, the adjusted risk of revision THA at 3 years was not different from 1998 to 2002 (4.70%) and 2008 to 2010 (4.03%; p = 0.1176). Similarly, the adjusted risk of revision at 1 year did not differ from 1998 to 2002 (2.83%) and 2008 to 2010 (2.42%; p = 0.3386). Patients with more comorbidities had a greater adjusted risk of revision (p < 0.001) at all times: 94% (95% CI, 58%–138%) and 56% (95% CI, 33%–84%) at 1 year and 7 years, respectively, for Charlson score of 5+ vs 0). Although the mid-term (5 and 7 years) risk of revision THA has decreased during the past 14 years among Medicare beneficiaries who underwent primary THA, the short-term risk has not. These findings suggest that greater clinical, research, and policy emphasis is needed to identify potentially avoidable causes of early failure after primary THA in patients in the Medicare population, and multistakeholder solutions are needed to optimize short-term outcomes. Level III, therapeutic study.

Background: Patients with morbid obesity, defined as body mass index of greater than 40 kg/m2, are being referred for weight loss and bariatric surgery before being accepted for a total knee arthroplasty (TKA). Previous studies have identified the risks associated with doing a TKA in an individual with an increased body mass index. We now present data identifying the same risks in individuals who have undergone bariatric surgery before submitting to TKA. Questions/Purposes: (1) Has the bariatric surgery improved the risk profile for the subsequent TKA? (2) Does the type of bariatric procedure matter? Method: A retrospective cohort study was conducted of patients who underwent bariatric surgery followed by TKA using Medicare hospital claims data. A study was undertaken using the Current Procedure Terminology codes and International Classification of Diseases-9 and International Classification of Diseases-10 for bariatric surgery. These identified entries were then cross-referenced to individuals who later underwent TKA, identified by CPT 27447, between 2004 and 2016. Twelve different types of complications which occurred in the 90-day period after the TKA were analyzed. Results: Postbariatric bypass surgery patients showed a markedly elevated risk in most complications examined. In each category, the type of previous gastric surgery had notable differences in the post-TKA complication profile. In the implant failure category, the data demonstrated an even greater risk after a gastric bypass. When postbariatric patients were compared with morbidly obese individuals who had not undergone bariatric surgery, the hazard ratios (HRs) were markedly elevated for death (HR 1.47/bypass), implant failure (HR 1.58/sleeve), and pneumonia (HR 1.68/bypass). Conclusion: (1) Submitting to bariatric surgery is not sufficient to normalize risks. (2) The type of previous bariatric procedure is associated with the type of complications encountered. (3) We were unable to attribute TKA to bariatric failures. (4) Health systems and health care providers should be cautious in withholding care for patients with morbid obesity.

STUDY DESIGN Vertebral compression fracture (VCF) patients in the 100% US Medicare data set (2005-2009). OBJECTIVE To compare the mortality and morbidity risks for VCF patients undergoing conservative treatment (nonoperated), balloon kyphoplasty (BKP), and vertebroplasty (VP). SUMMARY OF BACKGROUND DATA Studies have reported lower mortality risk for BKP or VP cohorts than nonoperated cohorts, but it is uncertain whether there are any differences in morbidity risks. METHODS Survival and morbidity was estimated by the Kaplan-Meier method, and the differences in outcomes were assessed by Cox regression between BKP, VP, and nonoperated cohorts. A propensity matching analysis was used to account for potential bias. RESULTS A total of 1,038,956 VCF patients were identified, including 141,343 BKP patients and 75,364 VP patients. The nonoperated cohort was found to have a 55% higher adjusted risk of mortality (P < 0.001) than the BKP cohort and 25% higher adjusted risk of mortality (P < 0.001) than the VP cohort. The BKP cohort was also found to have a 19% lower adjusted risk of mortality (P < 0.001) than the VP cohort. The findings were similar for mortality with pneumonia diagnosed in the 90 days before death and also after propensity matching, as well as for subgroups of osteoporotic VCF patients, including those who survived at least 1 year and those with no cancer diagnosis. With propensity matching, the nonoperated cohort had significantly higher adjusted risks of pneumonia, myocardial infarction/cardiac complications, DVT, and urinary tract infection than the BKP cohort but lower adjusted risks of subsequent augmentation/fusion, subsequent augmentation, and pulmonary/respiratory complications. The BKP cohort also had significantly lower risks of morbidity than the VP cohort, except for deep venous thrombosis (DVT), infection, and myocardial infarction/cardiac complications, which were similar between both cohorts. CONCLUSION VCF patients in the Medicare population who received vertebral augmentation therapies, specifically BKP and VP, experienced lower mortality and overall morbidity than VCF patients who received conservative management. LEVEL OF EVIDENCE 3.

Background: Few studies have explored the role of the National Health Expenditure and macroeconomics on the utilization of total joint replacement. The economic downturn has raised questions about the sustainability of growth for total joint replacement in the future. Previous projections of total joint replacement demand in the United States were based on data up to 2003 using a statistical methodology that neglected macroeconomic factors, such as the National Health Expenditure. Methods: Data from the Nationwide Inpatient Sample (1993 to 2010) were used with United States Census and National Health Expenditure data to quantify historical trends in total joint replacement rates, including the two economic downturns in the 2000s. Primary and revision hip and knee arthroplasty were identified using codes from the International Classification of Diseases, Ninth Revision, Clinical Modification. Projections in total joint replacement were estimated using a regression model incorporating the growth in population and rate of arthroplasties from 1993 to 2010 as a function of age, sex, race, and census region using the National Health Expenditure as the independent variable. The regression model was used in conjunction with government projections of National Health Expenditure from 2011 to 2021 to estimate future arthroplasty rates in subpopulations of the United States and to derive national estimates. Results: The growth trend for the incidence of joint arthroplasty, for the overall United States population as well as for the United States workforce, was insensitive to economic downturns. From 2009 to 2010, the total number of procedures increased by 6.0% for primary total hip arthroplasty, 6.1% for primary total knee arthroplasty, 10.8% for revision total hip arthroplasty, and 13.5% for revision total knee arthroplasty. The National Health Expenditure model projections for primary hip replacement in 2020 were higher than a previously projected model, whereas the current model estimates for total knee arthroplasty were lower. Conclusions: Economic downturns in the 2000s did not substantially influence the national growth trends for hip and knee arthroplasty in the United States. These latest updated projections provide a basis for surgeons, hospitals, payers, and policy makers to plan for the future demand for total joint replacement surgery.

BackgroundPatient, surgeon, health system, and device factors are all known to influence outcomes in total knee arthroplasty (TKA). However, patient-related factors associated with an increased risk of early failure are not well understood, particularly in elderly patients.Questions/purposesThe purpose of this study was to identify specific comorbid conditions associated with increased risk of early revision in Medicare patients undergoing TKA.MethodsA total of 117,903 Medicare patients who underwent primary TKA between 1998 and 2010 were identified from the Medicare 5% national sample administrative database and used to determine the relative risk of revision within 12 months after primary TKA as a function of baseline medical comorbidities. Cox regression was used to evaluate the impact of 29 comorbid conditions on risk of early failure controlling for age, sex, race, census region, socioeconomic status, and all other baseline comorbidities.ResultsThe most significant independent risk factors for revision TKA within 12 months were chronic pulmonary disease, depression, alcohol abuse, drug abuse, renal disease, hemiplegia or paraplegia, and obesity.ConclusionsThis information could be valuable to patients and their surgeons when making shared medical decisions regarding elective TKA and for risk-stratifying publicly reported outcomes in Medicare patients undergoing TKA.

BackgroundPatient, surgeon, health system, and device factors are all known to influence outcomes in THA. However, patient-related factors associated with an increased risk of early failure are poorly understood, particularly in elderly patients.Questions/purposesWe identified specific demographic and clinical characteristics associated with increased risk of early revision in Medicare patients with THA.MethodsThe Medicare 5% national sample administrative database was used to calculate the relative risk of revision within 12 months following primary THA as a function of baseline medical comorbidities in 56,030 Medicare patients who underwent primary THA between 1998 and 2010. The impact of 29 comorbid conditions on risk of early revision was examined using Cox regression, controlling for age, sex, race, US Census region, socioeconomic status, and all other baseline comorbidities.ResultsDepression, rheumatologic disease, psychoses, renal disease, chronic urinary tract infection, and congestive heart failure were associated with revision THA within 12 months of the index arthroplasty (p ≤ 0.038 for all comparisons; risk factors listed in order of significance).ConclusionsThis information is important when counseling elderly patients with THA regarding the risk of early failure and for risk stratifying publicly reported outcomes in Medicare patients with THA.

Background: The patient-related risk factors for periprosthetic joint infection and postoperative mortality in elderly patients undergoing total hip arthroplasty are poorly understood. The purpose of this study was to identify the specific patient comorbidities that are associated with an increased risk of periprosthetic joint infection and of ninety-day postoperative mortality in U.S. Medicare patients undergoing total hip arthroplasty. Methods: The Medicare 5% sample claims database was used to calculate the relative risk of periprosthetic joint infection and of ninety-day postoperative mortality as a function of preexisting comorbidities in 40,919 patients who underwent primary total hip arthroplasty between 1998 and 2007. The impact of twenty-nine comorbid conditions on periprosthetic joint infection and on postoperative mortality was examined with use of Cox regression, controlling for age, sex, census region, public assistance, and all other baseline comorbidities. The adjusted hazard ratios for all comorbid conditions were evaluated, and the Wald chi-square statistic was used to rank the degree of association of each condition with periprosthetic joint infection and with postoperative mortality. The Bonferroni-Holm method was used to adjust for the multiple comparisons resulting from the number of comorbid conditions analyzed. Results: Comorbid conditions associated with an increased adjusted risk of periprosthetic joint infection (in decreasing order of significance, p < 0.05 for all comparisons) were rheumatologic disease (hazard ratio [HR] = 1.71), obesity (HR = 1.73), coagulopathy (HR = 1.58), and preoperative anemia (HR = 1.36). Comorbid conditions associated with an increased adjusted risk of ninety-day postoperative mortality (in decreasing order of significance, p < 0.05 for all comparisons) were congestive heart failure (HR = 2.11), metastatic cancer (HR = 3.14), psychosis (HR = 1.85), renal disease (HR = 1.98), dementia (HR = 2.04), hemiplegia or paraplegia (HR = 2.62), cerebrovascular disease (HR = 1.40), and chronic pulmonary disease (HR = 1.32). Conclusions: We identified specific patient comorbidities that were independently associated with an increased risk of periprosthetic joint infection and of ninety-day postoperative mortality in Medicare patients who had undergone total hip arthroplasty. This information is important when counseling elderly patients regarding the risks of periprosthetic joint infection and mortality following total hip arthroplasty, as well as for risk adjustment of publicly reported total hip arthroplasty outcomes. Level of Evidence: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

The impact of specific baseline comorbid conditions on the relative risk of postoperative mortality and periprosthetic joint infection (PJI) in elderly patients undergoing TKA has not been well defined.We calculated the relative risk of postoperative mortality and PJI associated with 29 comorbid conditions in Medicare patients undergoing TKA.The Medicare 5% sample was used to calculate the relative risk of 90-day postoperative mortality and PJI as a function of 29 preexisting comorbid conditions in 83,011 patients who underwent primary TKA between 1998 and 2007.The independent risk factors for 90-day postoperative mortality (in decreasing order of significance) were congestive heart failure, metastatic cancer, renal disease, peripheral vascular disease, cerebrovascular disease, lymphoma, cardiac arrhythmia, dementia, pulmonary circulation disorders, and chronic liver disease. The independent risk factors for PJI (in decreasing order of significance) were congestive heart failure, chronic pulmonary disease, preoperative anemia, diabetes, depression, renal disease, pulmonary circulation disorders, obesity, rheumatologic disease, psychoses, metastatic tumor, peripheral vascular disease, and valvular disease.We believe this information important when counseling elderly patients regarding the risks of mortality and PJI after TKA and risk-adjusting publicly reported TKA patient outcomes.

Retrospective cohort study using a nationally representative inpatient database.To quantify the national revision burden for lumbar total disc replacements (TDRs) in the United States following Food and Drug Administration approval, for comparison with lumbar fusion and other common orthopedic procedures, including hip and knee replacement.Previous studies of revision lumbar TDR surgery have been based on IDE studies. The epidemiology and costs of TDR revision surgery from a national perspective have not yet been reported.The Nationwide Inpatient Sample was used to identify primary and revision TDR and anterior fusion procedures in 2005 and 2006. Surgeries were identified in the Nationwide Inpatient Sample using ICD9-CM codes. The prevalence of TDR and fusion surgery was calculated as a function of age, gender, race, census region, primary payer class, and type of hospital. Average length of stay and total hospitalization costs were also computed for each type of procedure.During the study period, there was a national total of 7172 TDR and 62,731 anterior fusion surgeries, including both primary and revisions. Overall, TDR patients were younger and had less comorbidity than fusion surgery patients. The average revision burden for lumbar TDR and anterior fusion was 11.2% and 5.8%, respectively. The average length of stay for primary lumbar TDR was significantly shorter compared to revision TDR, primary anterior fusion, and revision anterior fusion (P0.0001). Both the primary and the revision surgery using the TDR surgery involved significantly lower total hospital costs relative to anterior fusion surgery (P0.0001). Including revision, the average costs per TDR procedure were lower than anterior and posterior lumbar fusion.Although the revision burden for TDR was significantly higher than fusion surgery, the TDR revision burden fell within the revision burden range of hip and knee replacement, which are generally considered successful and cost-effective procedures. Economically, the higher revision burden for TDRs was offset by lower costs for both the primary as well as the revision procedures relative to fusion.

Background: Hard-on-hard bearings offer the potential to improve the survivorship of total hip arthroplasty implants. However, the specific indications for the use of these advanced technologies remain controversial. The purpose of this study was to characterize the epidemiology of bearing surface utilization in total hip arthroplasty in the United States with respect to patient, hospital, geographic, and payer characteristics. Methods: The Nationwide Inpatient Sample database was used to analyze bearing type and demographic characteristics associated with 112,095 primary total hip arthroplasties performed in the United States between October 1, 2005, and December 31, 2006. The prevalence of each type of total hip arthroplasty bearing was calculated for population subgroups as a function of age, sex, census region, payer class, and hospital type. Results: The most commonly reported bearing was metal-on-polyethylene (51%) followed by metal-on-metal (35%) and ceramic-on-ceramic (14%). Metal-on-polyethylene bearings were most commonly reported in female Medicare patients who were sixty-five to seventy-four years old, while metal-on-metal and ceramic-on-ceramic bearings were most commonly reported in privately insured male patients who were less than sixty-five years old. Thirty-three percent of patients over sixty-five years old had a hard-on-hard bearing reported. There was substantial regional variation in bearing usage; the highest prevalence of metal-on-polyethylene bearings was reported in the Northeast and at nonteaching hospitals, and the highest prevalence of metal-on-metal bearings was reported in the South and at teaching hospitals. Conclusions: The usage of total hip arthroplasty bearings varies considerably by patient characteristics, hospital type, and geographic location throughout the United States. Despite uncertain advantages in older patients, hard-on-hard bearings are commonly used in patients over the age of sixty-five years. Further study is necessary to define the appropriate indications for these advanced technologies in total hip arthroplasty.

Background: Understanding the causes of failure and the types of revision total hip arthroplasty performed is essential for guiding research, implant design, clinical decision-making, and health-care policy. The purpose of the present study was to evaluate the mechanisms of failure and the types of revision total hip arthroplasty procedures performed in the United States with use of newly implemented ICD-9-CM (International Classification of Diseases, Ninth Revision, Clinical Modification) diagnosis and procedure codes related specifically to revision total hip arthroplasty in a large, nationally representative population. Methods: The Healthcare Cost and Utilization Project Nationwide Inpatient Sample database was used to analyze clinical, demographic, and economic data from 51,345 revision total hip arthroplasty procedures performed between October 1, 2005, and December 31, 2006. The prevalence of revision procedures was calculated for population subgroups in the United States that were stratified according to age, sex, diagnosis, census region, primary payer class, and type of hospital. The cause of failure, the average length of stay, and total charges were also determined for each type of revision arthroplasty procedure. Results: The most common type of revision total hip arthroplasty procedure performed was all-component revision (41.1%), and the most common causes of revision were instability/dislocation (22.5%), mechanical loosening (19.7%), and infection (14.8%). Revision total hip arthroplasty procedures were most commonly performed in large, urban, nonteaching hospitals for Medicare patients seventy-five to eighty-four years of age. The average length of hospital stay for all types of revision arthroplasties was 6.2 days, and the average total charges were $54,553. However, the average length of stay, average charges, and procedure frequencies varied considerably according to census region, hospital type, and type of revision total hip arthroplasty procedure performed. Conclusions: Hip instability and mechanical loosening are the most common indications for revision total hip arthroplasty in the United States. As further experience is gained with the new diagnosis and procedure codes specifically related to revision total hip arthroplasty, this information will be valuable in directing future research, implant design, and clinical decision-making. Level of Evidence: Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence.

Mesothelioma rates are declining toward background levels, although estimates of the background rate have varied. We expanded upon earlier analyses and provided a data-based estimate of the background rate. We analyzed US male and female patterns for five age groups using the National Cancer Institute's Surveillance Epidemiology and End Results registry data from 1973 to 2002. Age-specific and age-adjusted incidence rates per 1 000 000 persons per year, standardized to the 2000 US population, were calculated for total, pleural, and peritoneal mesothelioma. We also calculated rates for persons who attained working age after the US Occupational Safety and Health Administration asbestos exposure limits took effect. Mesothelioma rates observed among young males and females varied little over time. We observed a decline and convergence of recent male and female rates in older age groups, except those who are between the age of 60 and above, for whom the 2002 male rate was approximately five times greater than that of females. As expected, rates were higher in major shipyard areas on the West coast. Rates for persons with little or no opportunity for occupational asbestos exposure were 1.15 (95% confidence interval: 0.90-1.45) for men and 0.94 (95% confidence interval: 0.87-1.24) for women. Mesothelioma is rare in younger age groups, and rates have been relatively stable and similar for both sexes. Rates continue to decline in older age groups, but remain high for males at 60 years or older. Rates among females at older ages suggest an impact of occupational exposure. The background rate for persons below age 50 is approximately one per million, independent of sex. Future data are needed to estimate this rate for older age groups.

Background: Fewer short-term complications following total hip arthroplasty have been associated with greater hospital and surgeon procedure volume. It remains unclear if procedure volume is associated with longer-term clinical outcomes and revision rates. We examined the association between hospital and surgeon procedure volume and total hip arthroplasty revision rates in the Medicare population at six months to eight years postoperatively. Methods: A subset of the 1997 to 2004 Medicare claims data was used to identify primary and revision total hip arthroplasties. The Kaplan-Meier method and Cox regression analysis were used to determine revision rates and hazard ratios associated with hospital and surgeon procedure volumes at 0.5, two, five, and eight years postoperatively. Results: About one-third of the primary hip procedures were done at hospitals with the highest annual volumes of total hip arthroplasties (more than 100). Surgeons with an annual volume of more than fifty procedures performed approximately one-sixth of the primary total hip arthroplasties. Patients who had been operated on by these surgeons had a lower revision rate at six months than did patients treated by surgeons with an annual volume of six to ten or eleven to twenty-five procedures (adjusted hazards ratio, 1.67 and 1.63, respectively). There was no effect of surgeon volume at the time of longer-term follow-up. Conclusions: The majority of the total hip arthroplasties in the Medicare population from 1997 to 2004 were not performed by the highest-volume hospitals or surgeons. Our findings suggest that patients of low-volume surgeons have a greater risk of arthroplasty revision at six months but no greater risk of revision at the time of longer-term follow-up. There appeared to be no significant association between hospital volume and the rate of revisions of total hip arthroplasties. Level of Evidence: Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence.

A recent analysis of historical procedure data indicated that the prevalence of primary and revision total hip and total knee arthroplasty increased steadily between 1990 and 20021. A massive demand for primary and revision surgeries is also expected in the next two decades2. Similarly, the overall incidence of deep infection also has increased substantially between 1990 and 2003 for both total hip arthroplasty and total knee arthroplasty3. In 2003, approximately 1.2% of the total hip arthroplasties performed in the United States were associated with deep infection, which was similar to the rate seen for total knee arthroplasties3. Deep infection is a catastrophic complication of both total hip and total knee arthroplasty, and it also represents a tremendous economic burden4,5. The implications for a growing incidence of infections, coupled with accelerating demand for arthroplasty, remain unexplored. Long-term survival of total hip arthroplasty and total knee arthroplasty implants has been investigated by Scandinavian arthroplasty registries6-8. However, in the United States, national hip and knee registries have not been established9,10. Medicare claims data have been used effectively in longitudinal analysis of mortality and morbidity following joint replacement11, but the feasibility of using this data as a registry substitute is unclear. Along with the projected increase in the utilization of total hip arthroplasty and total knee arthroplasty2, retrospective studies have shown increasing disparity between Medicare reimbursement and hospital charges, with higher charges for revision than for primary procedures12-14. The economic consequences of the projected demand for total hip arthroplasty and total knee arthroplasty are still unknown. The goals of our study were to (1) quantify the future number of infections at the site of arthroplasties done …

Work-related exposures potentially associated with a cluster of brain tumors at a petroleum exploration and extraction research facility were evaluated in a nested case-control study. Fifteen cases were identified in the original cohort and 150 matched controls were selected. Odds ratios (ORs) for occupational exposure to petroleum, radiation, solvents, magnetic fields, and work activities were near or below 1.0. ORs near 1.5 were observed for: working with computers (OR = 1.47; 95% confidence interval [CI] = 0.30-9.35); work-related travel (OR = 1.48; 95% CI = 0.25-5.95), and travel immunizations (OR = 1.62; 95% CI = 0.23-9.45). Higher ORs were observed for work in administrative and marketing buildings and for achieving a master's or higher degree (OR = 2.0, 95% CI = 0.4-10.7). While some ORs above 1.5 were noted, no work-related chemical and physical exposures were significantly associated with the occurrence of brain tumors among employees at this facility.

Introduction: The healthcare costs and clinical outcomes for Medicare beneficiaries undergoing revision procedures for CIED (ICD and CRT-D) were evaluated. Methods: The Medicare cohort for this study was defined by the following criteria: (a) ≥ 65 years old (b) implanted with a primary ICD/CRT-D in 2004 or 2005, (c) survived through 2012 and (c) underwent their 1st revision for a generator replacement (ERI) only. Patients were excluded if the procedures were associated with a recall, complication, or faulty lead. Total medical costs for the observation period, including subsequent revisions (≥ 2 revisions) and 6 month follow-up care due to complications, were identified from the reimbursement claim amounts. Costs were adjusted to 2014 US$. Results: Just over one thousand (ICD=605, CRT-D=408) t met the inclusion criteria.. This cohort of revised patients was composed primarily of men (~75%) and were between the ages of 65-74 years (>60%). Nineteen percent of patients had a Charlson Comorbidity Index score of 5 or higher, indicating substantial comorbidity. The total health care cost of these patients was approximately $185M, with just over half of the cost coming from ICD patients. Patients that had received only one revision over the eight year time period accounted for 92% of the population and cost on average $183K per patient over the study period. Patients who had undergone multiple generator replacement procedures accounted for 8% of the study cohort and cost on average $213K per patient over eight years. Preliminary cost analysis of complications associated with these revision procedures suggested that complications were also a significant financial burden. Conclusion: CIED revisions due to ERI are associated with a substantial clinical and financial burden. Minimizing the number of revisions will reduce the financial burden of CIED procedures. Evaluation of the costs for individual infection (sepsis, endocarditis etc.) and non-infection complications (cardiac perforation, hematoma etc.) is also underway.

The economic burden to Medicare due to revision arthroplasty procedures has not yet been studied systematically. The economic burden of revisions was calculated as annual reimbursements for revision arthroplasties relative to the sum total reimbursements of primary and revision arthroplasties. We evaluated this revision burden for total hip and knee arthroplasties through investigation of trends in charges and reimbursements in the Medicare population (Parts A and B claims from 1997-2003), while taking into account age and gender effects. Mean annual economic revision burdens were 18.8% (range, 17.4-20.2%) and 8.2% (range, 7.5-9.2%) for total hip arthroplasties and total knee arthroplasties, respectively. Procedural charges increased while reimbursements decreased over the study period, with higher charges observed for revisions than primary arthroplasties. Reimbursements per procedure were 62% to 68% less than associated charges for primary and revision total hip and knee arthroplasties. The effect of age and gender on reimbursements varied by procedure type. Unless some limiting mechanism is implemented to reduce the incidence of revision surgeries, the diverging trends in reimbursements and charges for total hip and knee arthroplasties indicate that the economic impact to the Medicare population and healthcare system will continue to increase.Prognostic study, level II-1 (retrospective study). See Guidelines for Authors for a complete description of levels of evidence.

A cohort mortality study was conducted among 3,779 employees at a petroleum exploration and extraction research facility to evaluate workplace exposures and brain tumor risk. Deaths were identified by searches against the National Death Index, Social Security Administration, and California state mortality files. Work histories were classified by job titles, laboratory activity, and company division. Eleven brain tumor deaths were observed among the cohort (standardized mortality ratio [SMR] 1.8; 95% confidence interval = 0.9-3.2). SMR analyses for scientists, employment in laboratory work, and in the research division were not associated with an increased brain tumor SMR, whereas an increased SMR was observed for administrative and nonresearch employees. Although conclusions are limited by the small study population and lack of specific exposure data, these findings were not consistent with an occupational explanation for the observed brain tumor cluster.

The objectives of this study were to evaluate whether there were higher rates of primary congenital hypothyroidism (PCH) or elevated concentrations of thyroid-stimulating hormone (TSH) in a community where perchlorate was detected in groundwater wells. The adjusted PCH prevalence ratio and 95% confidence interval (CI) comparing the study community to San Bernardino and Riverside counties combined was 0.45 (95% CI=0.06-1.64). The odds ratios for elevated TSH concentration were 1.24 (95% CI=0.89-1.68) among all newborns screened and 0.69 (95% CI=0.27-1.45) for newborns whose age at screening was 18 hours or greater. Age of the newborn at time of screening was the most important predictor of the TSH level. These findings suggest that residence in a community with potential perchlorate exposure has not impacted PCH rates or newborn thyroid function.

Open heart valve repair/replacement is widely used to treat various valvular pathologies. The development of percutaneous valve replacement technology may pave the way for less invasive treatment options. This study characterized the epidemiology of valvular repair and replacement procedures in the U.S. The Nationwide Inpatient Sample (NIS) was used to identify closed and open heart valvotomy, heart valve replacement, annuloplasty, and percutaneous valvotomy procedures between 1993 and 2007. NIS is an annual survey of ∼1,000 hospitals and contains 20% of the U.S. inpatient hospitalizations. The prevalence of these procedures was calculated as a function of age, gender, race, census region, and type of hospital. 3,342 closed heart valvotomy, 191,141 closed heart valvotomy, 1,078,388 heart valve replacement, 106,110 annuloplasty, and 35,071 percutaneous valvotomy procedures were identified. Heart valve replacements included 302,932, 89,249, 13,828, and 4,680 aortic, mitral, pulmonary, and tricuspid valve procedures with tissue graft, respectively, and 479,168, 253,804, 3,904, and 7,494 prosthetic aortic, mitral, pulmonary, and tricuspid valve procedures, respectively. In contrast to valvotomy procedures, the majority of heart valve replacements (64.0%) and annuloplasty (57.7%) were performed on elderly patients (>=65 years). Most repair/replacement procedures were performed on men, except for percutaneous valvotomy (41.9%). Regional variations were found; for example, closed valvotomy were disproportionately performed in South (44.2%). The vast majority of procedures were performed in urban, non-teaching and large hospitals. Databases such as the NIS allow the characterization of the epidemiology for heart valve repair/replacement patients in a large, nationally representative patient sample. Our study demonstrates that these procedures vary considerably by patient demographics and geographic region. Additional research will help assess if the epidemiology will change over time, as the use of new technologies such as percutaneous heart valve devices grows. In the future, longitudinal administrative databases, such as Medicare, provide a mechanism to evaluate the comparative effectiveness of these procedures.

The online version of the original article can be found under doi:10.1007/s11999-013-3045-0.

Background: The purpose of this study was to quantify the procedural rate and revision burden of total hip and knee arthroplasty in the United States and to determine if the age or gender-based procedural rates and overall revision burden are changing over time. Methods: The National Hospital Discharge Survey (NHDS) for 1990 through 2002 was used in conjunction with United States Census data to quantify the rates of primary and revision arthroplasty as a function of age and gender within the United States with use of methodology published by the American Academy of Orthopaedic Surgeons. Poisson regression analysis was used to evaluate the procedural rate and to determine year-to-year trends in primary and revision arthroplasty rates as a function of both age and gender. Results: Both the number and the rate of total hip and knee arthroplasties (particularly knee arthroplasties) increased steadily between 1990 and 2002. Over the thirteen years, the rate of primary total hip arthroplasties per 100,000 persons increased by approximately 50%, whereas the corresponding rate of primary total knee arthroplasties almost tripled. The rate of revision total hip arthroplasties increased by 3.7 procedures per 100,000 persons per decade, and that of revision total knee arthroplasties, by 5.4 procedures per 100,000 persons per decade. However, the mean revision burden of 17.5% for total hip arthroplasty was more than twice that for total knee arthroplasty (8.2%), and this did not change substantially over time. Conclusions: The number and prevalence of primary hip and knee replacements increased substantially in the United States between 1990 and 2002, but the trend was considerably more pronounced for primary total knee arthroplasty. Clinical Relevance: The reported prevalence trends have important ramifications with regard to the number of joint replacements expected to be performed by orthopaedic surgeons in the future. Because the revision burden has been relatively constant over time, we can expect that a greater number of primary replacements will result in a greater number of revisions unless some limiting mechanism can be successfully implemented to reduce the future revision burden.