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Background: Paraesophageal hernia repairs (PEHRs) have high rates of radiographic recurrence, with some patients requiring repeat operation. This study characterizes patients who underwent PEHR to identify the factors associated with postoperative symptom improvement and radiographic recurrence. We furthermore use propensity score matching to compare patients undergoing initial and reoperative PEHR to identify the factors predictive of recurrence or need for reoperation. Methods: After IRB approval, patients who underwent PEHR at a tertiary care center between January 2018 and December 2022 were identified. Patient characteristics, preoperative imaging, operative findings, and postoperative outcomes were recorded. A computational generalization of inverse propensity score weight was then used to construct populations of initial and redo PEHR patients with similar covariate distributions. Results: A total of 244 patients underwent PEHR (78.7% female, mean age 65.4 ± 12.3 years). Most repairs were performed with crural closure (81.4%) and fundoplication (71.7%) with 14.2% utilizing mesh. Postoperatively, 76.5% of patients had subjective symptom improvement and of 157 patients with postoperative imaging, 52.9% had evidence of radiographic recurrence at a mean follow-up of 10.4 ± 13.6 months. Only 4.9% of patients required a redo operation. Hernia type, crural closure, fundoplication, and mesh usage were not predictors of radiographic recurrence or symptom improvement (P> 0.05). Propensity weight score analysis of 50 redo PEHRs compared to a matched cohort of 194 initial operations revealed lower rates of postoperative symptom improvement (P< 0.05) but no differences in need for revision, complication rates, ED visits, or readmissions. Conclusions: Most PEHR patients have symptomatic improvement with minimal complications and reoperations despite frequent radiographic recurrence. Hernia type, crural closure, fundoplication, and mesh usage were not significantly associated with recurrence or symptom improvement. Compared to initial PEHR, reoperative PEHRs had lower rates of symptom improvement but similar rates of recurrence, complications, and need for reoperation.

Background: Enrollment of Medicare beneficiaries in medicare advantage (MA) plans has been steadily increasing. Prior research has shown differences in healthcare access and outcomes based on Medicare enrollment status. This study sought to compare utilization of minimally invasive colorectal cancer (CRC) surgery and postoperative outcomes between MA and Fee-for-Service (FFS) beneficiaries. Methods: A retrospective cohort study of beneficiaries  ≥ 65.5 years of age enrolled in FFS and MA plans was performed of patients undergoing a CRC resection from 2016 to 2019. The primary outcome was operative approach, defined as minimally invasive (laparoscopic) or open. Secondary outcomes included robotic assistance, hospital length-of-stay, mortality, discharge disposition, and hospital readmission. Using balancing weights, we performed a tapered analysis to examine outcomes with adjustment for potential confounders. Results: MA beneficiaries were less likely to have lymph node (12.9 vs 14.4%, p< 0.001) or distant metastases (15.5% vs 17.0%, p< 0.001), and less likely to receive chemotherapy (6.2% vs 6.7%, p< 0.001), compared to FFS beneficiaries. MA beneficiaries had a higher risk-adjusted likelihood of undergoing laparoscopic CRC resection (OR 1.12 (1.10–1.15), p< 0.001), and similar rates of robotic assistance (OR 1.00 (0.97–1.03), p= 0.912), compared to FFS beneficiaries. There were no differences in risk-adjusted length-of-stay (βcoefficient 0.03 (− 0.05–0.10), p= 0.461) or mortality at 30-60-and 90-days (OR 0.99 (0.95–1.04), p= 0.787; OR 1.00 (0.96–1.04), p= 0.815; OR 0.98 (0.95–1.02), p= 0.380). MA beneficiaries had a lower likelihood of non-routine disposition (OR 0.77 (0.75–0.78), p< 0.001) and readmission at 30-60-and 90-days (OR 0.76 (0.73–0.80), p< 0.001; OR 0.78 (0.75–0.81), p< 0.001; OR 0.79 (0.76–0.81), p< 0.001). Conclusions: MA beneficiaries had less advanced disease at the time of CRC resection and a greater likelihood of undergoing a laparoscopic procedure. MA enrollment is associated with improved health outcomes for elderly beneficiaries undergoing operative treatment for CRC.

Soumerai and Koppel (1) make the case against the use of instrumental variables (IVs) in outcomes research. While they do not explicitly call for a halt to the use of [...]

IMPORTANCE: The benefit of primary care physician (PCP) follow-up as a potential means to reduce readmissions in hospitalized patients has been found in other medical conditions and among patients receiving high-risk surgery. However, little is known about the implications of PCP follow-up for patients with an emergency general surgery (EGS) condition. OBJECTIVE: To evaluate the association between PCP follow-up and 30-day readmission rates after hospital discharge for an EGS condition. DESIGN, SETTING, AND PARTICIPANTS: This cohort study used data from the Centers for Medicare & Medicaid Services Master Beneficiary Summary File, Inpatient, Carrier (Part B), and Durable Medical Equipment files for beneficiaries aged 66 years or older who were hospitalized with an EGS condition that was managed operatively or nonoperatively between September 1, 2016, and November 30, 2018. Eligible patients were enrolled in Medicare fee-for-service, admitted through the emergency department with a primary diagnosis of an EGS condition, and received a general surgery consultation during the admission. Data were analyzed between July 11, 2022, and June 5, 2023. EXPOSURE: Follow-up with a PCP within 30 days after hospital discharge for the index admission. MAIN OUTCOMES AND MEASURES: The primary outcome was readmission within 30 days after discharge for the index admission. An inverse probability weighted regression model was used to estimate the risk-adjusted association of PCP follow-up with 30-day readmission. The secondary outcome was readmission within 30 days after discharge stratified by treatment type (operative vs nonoperative treatment) during their index admission. RESULTS: The study included 345 360 Medicare beneficiaries (mean [SD] age, 74.4 [12.0] years; 187 804 females [54.4%]) hospitalized with an EGS condition. Of these, 156 820 patients (45.4%) had a follow-up PCP visit, 108 544 (31.4%) received operative treatment during their index admission, and 236 816 (68.6%) received nonoperative treatment. Overall, 58 253 of 332 874 patients (17.5%) were readmitted within 30 days after discharge for the index admission. After risk adjustment and propensity weighting, patients who had PCP follow-up had 67% lower odds of readmission (adjusted odds ratio [AOR], 0.33; 95% CI, 0.31-0.36) compared with patients without PCP follow-up. After stratifying by treatment type, patients who were treated operatively during their index admission and had subsequent PCP follow-up within 30 days after discharge had 79% reduced odds of readmission (AOR, 0.21; 95% CI, 0.18-0.25); a similar association was seen among patients who were treated nonoperatively (AOR, 0.36; 95% CI, 0.34-0.39). Infectious conditions, heart failure, acute kidney failure, and chronic kidney disease were among the most frequent diagnoses prompting readmission overall and among operative and nonoperative treatment groups. CONCLUSIONS AND RELEVANCE: In this cohort study, follow-up with a PCP within 30 days after discharge for an EGS condition was associated with a significant reduction in the adjusted odds of 30-day readmission. This association was similar for patients who received operative care or nonoperative care during their index admission. In patients aged 66 years or older with an EGS condition, primary care coordination after discharge may be an important tool to reduce readmissions.

IMPORTANCE: Sixty-five million individuals in the US live in primary care shortage areas with nearly one-third of Medicare patients in need of a primary care health care professional. Periodic health examinations and preventive care visits have demonstrated a benefit for surgical patients; however, the impact of primary care health care professional shortages on adverse outcomes from surgery is largely unknown. OBJECTIVE: To determine if preoperative primary care utilization is associated with postoperative mortality following an emergency general surgery (EGS) operation among Black and White older adults. DESIGN, SETTING, AND PARTICIPANTS: This was a retrospective cohort study that took place at US hospitals with an emergency department. Participants were Medicare patients aged 66 years or older who were admitted from the emergency department for an EGS condition between July 1, 2015, and June 30, 2018, and underwent an operation on hospital day 0, 1, or 2. The analysis was performed during December 2022. Patients were classified into 1 of 5 EGS condition categories based on principal diagnosis codes; colorectal, general abdominal, hepatopancreatobiliary, intestinal obstruction, or upper gastrointestinal. Mixed-effects multivariable logistic regression was used in the risk-adjusted models. An interaction term model was used to measure effect modification by race. EXPOSURE: Primary care utilization in the year prior to presentation for an EGS operation. MAIN OUTCOME AND MEASURES: In-hospital, 30-day, 60-day, 90-day, and 180-day mortality. RESULTS: A total of 102 384 patients (mean age, 73.8 [SD, 11.5] years) were included in the study. Of those, 8559 were Black (8.4%) and 93 825 were White (91.6%). A total of 88 340 patients (86.3%) had seen a primary care physician in the year prior to their index hospitalization. After risk adjustment, patients with primary care exposure had 19% lower odds of in-hospital mortality than patients without primary care exposure (odds ratio [OR], 0.81; 95% CI, 0.72-0.92). At 30 days patients with primary care exposure had 27% lower odds of mortality (OR, 0.73; 95% CI, 0.67-0.80). This remained relatively stable at 60 days (OR, 0.75; 95% CI, 0.69-0.81), 90 days (OR, 0.74; 95% CI, 0.69-0.81), and 180 days (OR, 0.75; 95% CI, 0.70-0.81). None of the interactions between race and primary care physician exposure for mortality at any time interval were significantly different. CONCLUSIONS AND RELEVANCE: In this observational study of Black and White Medicare patients, primary care utilization had no impact on in-hospital mortality for Black patients, but was associated with decreased mortality for White patients. Primary care utilization was associated with decreased mortality for both Black and White patients at 30, 60, 90 and 180 days

Inverse probability weights are commonly used in epidemiology to estimate causal effects in observational studies. Researchers often focus on either the average treatment effect or the average treatment effect on the treated with inverse probability weighting estimators. However, poor overlap in the baseline covariates between the treated and control groups can produce extreme weights that can result in biased treatment effect estimates. One alternative to inverse probability weights are overlap weights, which target the population with the most overlap on observed covariates. Although estimates based on overlap weights produce less bias in such contexts, the causal estimand can be difficult to interpret. An alternative to model-based inverse probability weights are balancing weights, which directly target imbalances during the estimation process, rather than model fit. Here, we explore whether balancing weights allow analysts to target the average treatment effect on the treated in cases where inverse probability weights lead to biased estimates due to poor overlap. We conduct three simulation studies and an empirical application. We find that balancing weights often allow the analyst to still target the average treatment effect on the treated even when overlap is poor. We show that although overlap weights remain a key tool, more familiar estimands can sometimes be targeted by using balancing weights.

IMPORTANCE: A surgical consultation is a critical first step in the care of patients with emergency general surgery conditions. It is unknown if Black Medicare patients and White Medicare patients receive surgical consultations at similar rates when they are admitted from the emergency department. OBJECTIVE: To determine whether Black Medicare patients have similar rates of surgical consultations when compared with White Medicare patients after being admitted from the emergency department with an emergency general surgery condition. DESIGN, SETTING, AND PARTICIPANTS: This was a retrospective cohort study that took place at US hospitals with an emergency department and used a computational generalization of inverse propensity score weight to create patient populations with similar covariate distributions. Participants were Medicare patients age 65.5 years or older admitted from the emergency department for an emergency general surgery condition between July 1, 2015, and June 30, 2018. The analysis was performed during February 2022. Patients were classified into 1 of 5 emergency general surgery condition categories based on principal diagnosis codes: colorectal, general abdominal, hepatopancreatobiliary, intestinal obstruction, and upper gastrointestinal. EXPOSURES: Black vs White race. MAIN OUTCOMES AND MEASURES: Receipt of a surgical consultation after admission from the emergency department with an emergency general surgery condition. RESULTS: A total of 1 686 940 patients were included in the study. Of those included, 214 788 patients were Black (12.7%) and 1 472 152 patients were White (87.3%). After standardizing for medical and diagnostic imaging covariates, Black patients had 14% lower odds of receiving a surgical consultation (odds ratio [OR], 0.86; 95% CI, 0.85-0.87) with a risk difference of −3.17 (95% CI, −3.41 to −2.92). After standardizing for socioeconomic covariates, Black patients remained at an 11% lower odds of receiving a surgical consultation compared with similar White patients (OR, 0.89; 95% CI, 0.88-0.90) with a risk difference of −2.49 (95% CI, −2.75 to −2.23). Additionally, when restricting the analysis to Black patients and White patients who were treated in the same hospitals, Black patients had 8% lower odds of receiving a surgical consultation when compared with White patients (OR, 0.92; 95% CI, 0.90-0.93) with a risk difference of −1.82 (95% CI, −2.18 to −1.46). CONCLUSIONS AND RELEVANCE: In this study, Black Medicare patients had lower odds of receiving a surgical consultation after being admitted from the emergency department with an emergency general surgery condition when compared with similar White Medicare patients. These disparities in consultation rates cannot be fully attributed to medical comorbidities, insurance status, socioeconomic factors, or individual hospital-level effects.

AbstractSocial scientists use the concept of interactions to study effect dependency. In the causal inference literature, interaction terms may be used in two distinct type of analysis. The first type of analysis focuses on causal interactions, where the analyst is interested in whether two treatments have differing effects when both are administered. The second type of analysis focuses on effect modification, where the analyst investigates whether the effect of a single treatment varies across levels of a baseline covariate. While both forms of interaction analysis are typically conducted using the same type of statistical model, the identification assumptions for these two types of analysis are very different. In this paper, we clarify the difference between these two types of interaction analysis. We demonstrate that this distinction is mostly ignored in the political science literature. We conclude with a review of several applications where we show that the form of the interaction is critical to proper interpretation of empirical results.

The 21-gene recurrence score (RS) is an established predictor of recurrence for early stage, hormone receptor positive breast cancer. The association between RS and other risk factors such as obesity has not been fully explored. We hypothesized that patients with obesity may present with primary breast cancers with higher recurrence scores.

AbstractA common causal identification strategy in political science is selection on observables. This strategy assumes one observes a set of covariates that is, after statistical adjustment, sufficient to make treatment status as-if random. Under adjustment methods such as matching or inverse probability weighting, coefficients for control variables are treated as nuisance parameters and are not directly estimated. This is in direct contrast to regression approaches where estimated parameters are obtained for all covariates. Analysts often find it tempting to give a causal interpretation to all the parameters in such regression models—indeed, such interpretations are often central to the proposed research design. In this paper, we ask when we can justify interpreting two or more coefficients in a regression model as causal parameters. We demonstrate that analysts must appeal to causal identification assumptions to give estimates causal interpretations. Under selection on observables, this task is complicated by the fact that more than one causal effect might be identified. We show how causal graphs provide a framework for clearly delineating which effects are presumed to be identified and thus merit a causal interpretation, and which are not. We conclude with a set of recommendations for how researchers should interpret estimates from regression models when causal inference is the goal.

Supplemental Digital Content is available in the text.

Do minority voters respond to co-racial or co-ethnic candidates? That is does the increased chance of substantive representation translate into increased participation? Here, we focus on this question among African American voters. While much of the empirical literature on this question has produced conflicting answers, recent studies suggest that minority candidates can significantly increase minority turnout. We argue that past work on this topic does not adequately account for the fact that minority voters in places with minority candidates may systematically differ in their level of participation than minority voters in places without minority candidates. In this study we address the weaknesses of previous research designs and offer a new design that exploits the redistricting process to gain additional leverage over this question. We find little evidence that African American voter turnout increases when voters are moved to African American candidates. We find some evidence that white voters, however, tend to vote at lower rates when they are represented by African American candidates.

Supplemental Digital Content is available in the text

We retrospectively studied the effect of introducing procalcitonin into clinical practice on antibiotic use within a large academic pediatric intensive care unit. In the absence of a standardized algorithm, availability of the procalcitonin assay did not reduce the frequency of antibiotic initiations or the continuation of antibiotics for greater than 72 hours.

IMPORTANCE: Important metrics of residency program success include the clinical outcomes achieved by trainees after transitioning to practice. Previous studies have shown significant differences in reported training experiences of general surgery residents at nonuniversity-based residency (NUBR) and university-based residency (UBR) programs. OBJECTIVE: To examine the differences in practice patterns and clinical outcomes between surgeons trained in NUBR and those trained in UBR programs. DESIGN, SETTING, AND PARTICIPANTS: This observational cohort study linked the claims data of patients who underwent general surgery procedures in New York, Florida, and Pennsylvania between January 1, 2012, and December 31, 2013, to demographic and training information of surgeons in the American Medical Association Physician Masterfile. Patients who underwent a qualifying procedure were grouped by surgeon. Practice pattern analysis was performed on 3638 surgeons and 1 237 621 patients, representing 214 residency programs. Clinical outcomes analysis was performed on 2301 surgeons and 312 584 patients. Data analysis was conducted from February 1, 2017, to July 31, 2017. EXPOSURES: NUBR or UBR training status. MAIN OUTCOMES AND MEASURES: Inpatient mortality, complications, and prolonged length of stay. RESULTS: No significant differences were observed between the NUBR-trained surgeons and UBR-trained surgeons in age (mean, 53.3 years vs 53.7 years), sex (female, 18.2% vs 16.9%), or years of clinical experience (mean, 16.5 years vs 16.5 years). Overall, NUBR-trained surgeons compared with UBR-trained surgeons performed more procedures (median interquartile range [IQR], 328 [93-661] vs 164 [49-444]; P < .001) and performed a greater proportion of procedures in the outpatient setting (risk difference, 6.5; 95% CI, 6.4 to 6.7; P < .001). Before matching, the mean proportion of patients with documented inpatient mortality was lower for NUBR-trained surgeons than for UBR-trained surgeons (risk difference, −1.01; 95% CI, −1.41 to −0.61; P < .001). The mean proportion of patients with complications (risk difference, −3.17%; 95% CI, −4.21 to −2.13; P < .001) and prolonged length of stay (risk difference, −1.89%; 95% CI, −2.79 to −0.98; P < .001) was also lower for NUBR-trained surgeons. After matching, no significant differences in patient mortality, complications, and prolonged length of stay were found between NUBR- and UBR-trained surgeons. CONCLUSIONS AND RELEVANCE: Surgeons trained in NUBR and UBR programs have distinct practice patterns. After controlling for patient, procedure, and hospital factors, no differences were observed in the inpatient outcomes between the 2 groups.

Supplemental Digital Content is available in the text

Supplemental Digital Content is available in the text.

Political scientists often attempt to exploit natural experiments to estimate causal effects. We explore how variation in geography can be exploited as a natural experiment and review several assumptions under which geographic natural experiments yield valid causal estimates. In particular, we focus on cases where a geographic or administrative boundary splits units into treated and control areas. The different identification assumptions we consider suggest testable implications, which we use to establish their plausibility. Our methods are illustrated with an original study of whether ballot initiatives increase turnout in Wisconsin and Ohio, which illustrates the strengths and weaknesses of causal inferences based on geographic natural experiments.

IMPORTANCE: Childhood suicidality (ie, suicidal ideation or attempts) rates are increasing, and attention-deficit/hyperactivity disorder (ADHD) and externalizing symptoms are common risk factors associated with suicidality. More data are needed to describe associations of ADHD pharmacotherapy with childhood suicidality. OBJECTIVE: To investigate the associations of ADHD pharmacotherapy with externalizing symptoms and childhood suicidality. DESIGN, SETTING, AND PARTICIPANTS: In this cohort study, cross-sectional and 1-year-longitudinal associations were examined using data (collected during 2016-2019) from the Adolescent Brain Cognitive Development (ABCD) Study, a large, diverse US sample of children aged 9 to 11 years. Data analysis was performed from November to December 2020. EXPOSURES: Main and interaction associations of externalizing symptoms (hyperactivity ADHD symptoms, oppositional defiant, and conduct disorder symptoms) and ADHD medication treatment (methylphenidate and amphetamine derivatives, a-2-agonists, and atomoxetine) at baseline assessment. MAIN OUTCOMES AND MEASURES: Child-reported suicidality (past and present at baseline; current at longitudinal assessment). Covariates were age, sex, race/ethnicity, parents’ education, marital status, and concomitant child psychiatric pharmacotherapy (antidepressants and antipsychotics). RESULTS: Among 11 878 children at baseline assessment (mean [SD] age,?9.9 [0.6] years; 6196 boys [52.2%]; 8805 White [74.1%]), 1006 (8.5%) were treated with ADHD medication and 1040 (8.8%) reported past or current suicidality. Externalizing symptoms (median?[range], 1 [0-29] symptom count) were associated with suicidality (for a change of 1 SD in symptoms, odds ratio [OR],?1.34; 95% CI, 1.26-1.42; P?<?.001), as was ADHD medication treatment (OR,?1.32; 95% CI, 1.06-1.64; P?=?.01). ADHD medication use was associated with less suicidality in children with more externalizing symptoms (significant symptom-by-medication interaction, B?=?-0.250; SE?=?0.086; P?=?.004), such that for children who were not receiving ADHD medications, there was an association between more externalizing symptoms and suicidality (for a change of 1 SD in symptoms, OR,?1.42; 95% CI, 1.33-1.52; P?<?.001); however, for children who were receiving ADHD medication, there was no such association (OR,?1.15; 95% CI, 0.97-1.35; P?=?.10). The association with medication remained even when covarying for multiple confounders, including risk and protective factors for suicidality in ABCD, and was replicated in 1-year longitudinal follow-up. Sensitivity analyses matching participants with high numbers of externalizing symptoms taking and not taking ADHD medication treatment confirmed its association with less suicidality. CONCLUSIONS AND RELEVANCE: These findings suggest that ADHD medication treatment is associated with less suicidality in children with substantial externalizing symptoms and may be used to inform childhood suicide prevention strategies.

Confounding by indication is a critical challenge in evaluating the effectiveness of surgical interventions using observational data. The threat from confounding is compounded when using medical claims data due to the inability to measure risk severity. If there are unobserved differences in risk severity across patients, treatment effect estimates based on methods such a multivariate regression may be biased in an unknown direction. A research design based on instrumental variables offers one possibility for reducing bias from unobserved confounding compared to risk adjustment with observed confounders. This study investigates whether a physician’s preference for operative care is a valid instrumental variable for studying the effect of emergency surgery. We review the plausibility of the necessary causal assumptions in an investigation of the effect of emergency general surgery (EGS) on inpatient mortality among adults using medical claims data from Florida, Pennsylvania, and New York in 2012–2013. In a departure from the extant literature, we use the framework of stochastic monotonicity which is more plausible in the context of a preference-based instrument. We compare estimates from an instrumental variables design to estimates from a design based on matching that assumes all confounders are observed. Estimates from matching show lower mortality rates for patients that undergo EGS compared to estimates based in the instrumental variables framework. Results vary substantially by condition type. We also present sensitivity analyses as well as bounds for the population level average treatment effect. We conclude with a discussion of the interpretation of estimates from both approaches.

In randomized controlled trials, the evaluation of an overall treatment effect is often followed by effect modification or subgroup analyses, where the possibility of a different magnitude or direction of effect for varying values of a covariate is explored. While studies of effect modification are typically restricted to pretreatment covariates, longitudinal experimental designs permit the examination of treatment effect modification by intermediate outcomes, where intermediates are measured after treatment but before the final outcome. We present a novel application of generalized structural mean models (GSMMs) for simultaneously assessing effect modification by post-treatment covariates and accounting for noncompliance to assigned treatment status. The proposed approach may also be used to identify post-treatment effect modifiers in the absence of noncompliance. The methods are evaluated using a simulation study that demonstrates that our approach retains consistent estimation of effect modification by intermediate variables that are affected by treatment and also predict outcomes. We illustrate the method using a randomized trial designed to promote re-employment through teaching skills to enhance self-esteem and inoculate job seekers against setbacks in the job search process. Our analysis provides some evidence that the intervention was much less successful among subjects that displayed higher levels of depression at intermediate post-treatment waves of the study. We also compare the assumptions of our approach and principal stratification as alternatives to account for differences in effects by intermediate variables.