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Objectives: To compare geographic variation in healthcare spending and utilization between the Military Health System (MHS) and Medicare across hospital referral regions (HRRs)., Study Design: Retrospective analysis., Methods: Data on age-, sex-, and race-adjusted Medicare per capita expenditure and utilization measures by HRR were obtained from the Dartmouth Atlas for 2007 to 2010. Similarly, adjusted data from 2007 and 2010 were obtained from the MHS Data Repository and patients assigned to HRRs. We compared high- and low-spending regions, and computed coefficient of variation (CoV) and correlation coefficients for healthcare spending, hospital inpatient days, hip surgery, and back surgery between MHS and Medicare patients., Results: We found significant variation in spending and utilization across HRRs in both the MHS and Medicare. CoV for spending was higher in the MHS compared with Medicare, (0.24 vs 0.15, respectively) and CoV for inpatient days was 0.36 in the MHS versus 0.19 in Medicare. The CoV for back surgery was also greater in the MHS compared with Medicare (0.47 vs 0.29, respectively). Per capita Medicare spending per HRR was significantly correlated to adjusted MHS spending (r = 0.3; P <.0001). Correlation in inpatient days (r = 0.29; P <.0001) and back surgery (r = 0.52; P <.0001) was also significant. Higher spending markets in both systems were not comparable; lower spending markets were located mostly in the Midwest., Conclusions: In comparing 2 systems with similar pricing schemes, differences in spending likely reflect variation in utilization and the influence of local provider culture.

Background: Effectiveness of carotid artery stenting (CAS) relative to carotid endarterectomy (CEA) among Medicare patients has not been established. We compared effectiveness of CAS versus CEA among Medicare beneficiaries., Methods and Results: We linked Medicare data (2000-2009) to the Society for Vascular Surgery's Vascular Registry (2005-2008) and the National Cardiovascular Data Registry's (NCDR) Carotid Artery Revascularization and Endarterectomy Registry (2006-2008/2009). Medicare patients were followed up from procedure date until death, stroke/transient ischemic attack, periprocedural myocardial infarction, or a composite end point for these outcomes. We derived high-dimensional propensity scores using registry and Medicare data to control for patient factors and adjusted for provider factors in a Cox regression model comparing CAS with CEA. Among 5254 Society for Vascular Surgery's Vascular Registry (1999 CAS; 3255 CEA) and 4055 Carotid Artery Revascularization and Endarterectomy Registry (2824 CAS; 1231 CEA) Medicare patients, CAS patients had a higher comorbidity burden and were more likely to be at high surgical risk (Society for Vascular Surgery's Vascular Registry: 96.7% versus 44.5%; Carotid Artery Revascularization and Endarterectomy Registry: 71.3% versus 44.7%). Unadjusted outcome risks were higher for CAS. Mortality risks remained elevated for CAS after adjusting for patient-level factors (hazard ratio, 1.24; 95% confidence interval, 1.06-1.46). After further adjustment for provider factors, differences between CAS and CEA were attenuated or no longer present (hazard ratio for mortality, 1.13; 95% confidence interval, 0.94-1.37). Performance was comparable across subgroups defined by sex and degree of carotid stenosis, but there was a nonsignificant trend suggesting a higher risk of adverse outcomes in older (>80) and symptomatic patients undergoing CAS., Conclusions: Outcomes after CAS and CEA among Medicare beneficiaries were comparable after adjusting for both patient- and provider-level factors., (© 2016 American Heart Association, Inc.)

Importance: Despite increased carotid artery stenting (CAS) dissemination following the 2005 National Coverage Determination, to our knowledge, periprocedural and long-term outcomes have not been described among Medicare beneficiaries., Objective: To describe the incidence of outcomes during and after the periprocedural period among Medicare beneficiaries undergoing CAS., Design, Setting, and Participants: Observational study with a mean follow-up time of approximately 2 years among 22,516 fee-for-service Medicare beneficiaries at least 66 years old undergoing CAS (2005-2009) who were linked to the Centers for Medicare & Medicaid Services' CAS database. Database procedure dates were required to fall during a Medicare hospitalization for CAS., Main Outcomes and Measures: Periprocedural (30-day) and long-term risks of mortality and stroke or transient ischemic attack, as well as periprocedural myocardial infarction. Subgroups were based on sociodemographic, clinical, and center-level factors, as well as the Stenting and Angioplasty With Protection in Patients at High Risk for Endarterectomy (SAPPHIRE) trial or Carotid Revascularization Endarterectomy vs Stenting Trial (CREST) enrollment criteria., Results: The mean patient age was 76.3 years, 60.5% were male, 93.8% were of white race, 91.2% were at high surgical risk, 47.4% were symptomatic, and 97.4% had carotid stenosis of at least 70%. Crude 30-day mortality, stroke or transient ischemic attack, and myocardial infarction risks were 1.7% (95% CI, 1.5%-1.8%), 3.3% (95% CI, 3.0%-3.5%), and 2.5% (95% CI, 2.3%-2.7%), respectively. Mortality during a mean follow-up time of 2 years was 32.0% (95% CI, 31.0%-33.0%), with rates of 37.3% (95% CI, 35.8%-38.7%) among symptomatic patients and 27.7% (95% CI, 26.4%-28.9%) among asymptomatic patients. Older age, symptomatic carotid stenosis, and nonelective hospital admission were associated with increased adjusted hazards of mortality and stroke or transient ischemic attack during and after the periprocedural period. The presence of a stroke center, government ownership, and a hospital bed capacity of 500 or more were associated with increased adjusted hazards of periprocedural mortality and stroke or transient ischemic attack. Few patients met the SAPPHIRE trial or CREST enrollment criteria primarily because physicians did not meet proficiency requirements either due to exceeding periprocedural complication trial thresholds or not meeting minimum CAS volume requirements., Conclusions and Relevance: Competing risks may limit the benefits of CAS in certain Medicare beneficiaries, particularly among older and symptomatic patients who have higher periprocedural and long-term mortality risks. The generalizability of trials like the SAPPHIRE or CREST to the Medicare population may be limited, underscoring the need to evaluate real-world effectiveness of carotid stenosis treatments.

Background: Confounding by indication is a serious threat to comparative studies using real world data. We assessed the utility of automated data-adaptive analytic approach for confounding adjustment when both claims and clinical registry data are available. Methods: We used a comparative study example of carotid artery stenting (CAS) vs. carotid endarterectomy (CEA) in 2005–2008 when CAS was only indicated for patients with high surgical risk. We included Medicare beneficiaries linked to the Society for Vascular Surgery's Vascular Registry >65 years old undergoing CAS/CEA. We compared hazard ratios (HRs) for death while adjusting for confounding by combining various 1) Propensity score (PS) modeling strategies (investigator-specified [IS-PS] vs. automated data-adaptive [ada-PS]); 2) data sources (claims-only, registry-only and claims-plus-registry); and 3) PS adjustment approaches (matching vs. quintiles-adjustment with/without trimming). An HR of 1.0 was used as a benchmark effect estimate based on CREST trial. Results: The cohort included 1,999 CAS and 3,255 CEA patients (mean age 76). CAS patients were more likely symptomatic and at high surgical risk, and experienced higher mortality (crude HR = 1.82 for CAS vs. CEA). HRs from PS-quintile adjustment without trimming were 1.48 and 1.52 for claims-only IS-PS and ada-PS, 1.51 and 1.42 for registry-only IS-PS and ada-PS, and 1.34 and 1.23 for claims-plus-registry IS-PS and ada-PS, respectively. Estimates from other PS adjustment approaches showed similar patterns. Conclusions: In a comparative effectiveness study of CAS vs. CEA with strong confounding by indication, ada-PS performed better than IS-PS in general, but both claims and registry data were needed to adequately control for bias. [ABSTRACT FROM AUTHOR]

Background--Clinical trials demonstrated the efficacy of carotid artery stenting (CAS) relative to carotid endarterectomy when performed by physicians with demonstrated proficiency. It is unclear how CAS performance may be influenced by the diversity in CAS and non-CAS provider volumes in routine clinical practice. Methods and Results--We linked Medicare claims to the Centers for Medicare and Medicaid Services' CAS Database (2005-2009). We assessed the association between 30-day mortality and past-year physician (0, 1-4, 5-9, 10-19, ≥20) and hospital (<10, 10-19, 20-39, ≥40) CAS volumes and past-year hospital coronary and peripheral stenting volumes (<200, 200-399, 400-849, ≥850) among beneficiaries at least 66 years of age. Unadjusted 30-day mortality risk was 1.8% (95% confidence interval [CI], 1.6-2.0) for 19 724 patients undergoing CAS by 2045 physicians in 729 hospitals. Median past-year CAS volume was 9 (interquartile range, 4-19) for physicians and 23 (interquartile range, 12-41) for hospitals. Compared to physicians performing ≥20 CAS in the past year, lower CAS volumes were associated with higher adjusted risks of 30-day morality (P value for trend < 0.05): 1.4 (95% CI, 0.9-2.3) for 0 past-year CAS, 1.3 (95% CI, 0.9-1.8) for 1 to 4, 1.1 (95% CI, 0.8-1.6) for 5 to 9, and 0.9 (95% CI, 0.7-1.4) for 10 to 19. An inverse relationship between 30-day mortality and past-year CAS hospital volume as well as past-year hospital non-CAS volume, past-year hospital non-CAS volume, and 30-day mortality was also noted. Conclusions--Among Medicare patients, an inverse relationship exists between physician and hospital CAS volumes and hospital non-CAS stenting volume and 30-day mortality, even after adjusting for all pertinent patient- and hospital-level factors. [ABSTRACT FROM AUTHOR]