Increasing Power for Observational Studies of Aberrant Response: An Adaptive Approach

Journal of the Royal Statistical Society Series B (Statistical Methodology) · 2021 · 12 citations

• Computer Science
• Econometrics
• Statistics

Abstract In many observational studies, the interest is in the effect of treatment on bad, aberrant outcomes rather than the average outcome. For such settings, the traditional approach is to define a dichotomous outcome indicating aberration from a continuous score and use the Mantel–Haenszel test with matched data. For example, studies of determinants of poor child growth use the World Health Organization’s definition of child stunting being height-for-age z-score ≤ − 2. The traditional approach may lose power because it discards potentially useful information about the severity of aberration. We develop an adaptive approach that makes use of this information and asymptotically dominates the traditional approach. We develop our approach in two parts. First, we develop an aberrant rank approach in matched observational studies and prove a novel design sensitivity formula enabling its asymptotic comparison with the Mantel–Haenszel test under various settings. Second, we develop a new, general adaptive approach, the two-stage programming method, and use it to adaptively combine the aberrant rank test and the Mantel–Haenszel test. We apply our approach to a study of the effect of teenage pregnancy on stunting.

Spending And Quality After Three Years Of Medicare’s Voluntary Bundled Payment For Joint Replacement Surgery

Health Affairs · 2020 · 66 citations

• Actuarial science
• Business
• Medicine

Medicare has reinforced its commitment to voluntary bundled payment by building upon the Bundled Payments for Care Improvement (BPCI) initiative via an ongoing successor program, the BPCI Advanced Model. Although lower extremity joint replacement (LEJR) is the highest-volume episode in both BPCI and BPCI Advanced, there is a paucity of independent evidence about its long-term impact on outcomes and about whether improvements vary by timing of participation or arise from patient selection rather than changes in clinical practice. We found that over three years, compared to no participation, participation in BPCI was associated with a 1.6 percent differential decrease in average LEJR episode spending with no differential changes in quality, driven by early participants. Patient selection accounted for 27 percent of episode savings. Our findings have important policy implications in view of BPCI Advanced and its two participation waves.

Effect of Default Options in Advance Directives on Hospital-Free Days and Care Choices Among Seriously Ill Patients

JAMA Network Open · 2020 · 50 citations

• Medicine
• Emergency medicine
• Nursing

Importance: There is limited evidence regarding how patients make choices in advance directives (ADs) or whether these choices influence subsequent care. Objective: To examine whether default options in ADs influence care choices and clinical outcomes. Design, Setting, and Participants: This randomized clinical trial included 515 patients who met criteria for having serious illness and agreed to participate. Patients were enrolled at 20 outpatient clinics affiliated with the University of Pennsylvania Health System and the University of Pittsburgh Medical Center from February 2014 to April 2016 and had a median follow-up of 18 months. Data analysis was conducted from November 2018 to April 2019. Interventions: Patients were randomly assigned to complete 1 of the 3 following ADs: (1) a comfort-promoting plan of care and nonreceipt of potentially life-sustaining therapies were selected by default (comfort AD), (2) a life-extending plan of care and receipt of potentially life-sustaining therapies were selected by default (life-extending AD), or (3) no choices were preselected (standard AD). Main Outcomes and Measures: This trial was powered to rule out a reduction in hospital-free days in the intervention groups. Secondary outcomes included choices in ADs for an overall comfort-oriented approach to care, choices to forgo 4 forms of life support, patients' quality of life, decision conflict, place of death, admissions to hospitals and intensive care units, and costs of inpatient care. Results: Among 515 patients randomized, 10 withdrew consent and 13 were later found to be ineligible, leaving 492 (95.5%) in the modified intention-to-treat (mITT) sample (median [interquartile range] age, 63 [56-70] years; 279 [56.7%] men; 122 [24.8%] black; 363 [73.8%] with cancer). Of these, 264 (53.7%) returned legally valid ADs and were debriefed about their assigned intervention. Among these, patients completing comfort ADs were more likely to choose comfort care (54 of 85 [63.5%]) than those returning standard ADs (45 of 91 [49.5%]) or life-extending ADs (33 of 88 [37.5%]) (P = .001). Among 492 patients in the mITT sample, 57 of 168 patients [33.9%] who completed the comfort AD, 47 of 165 patients [28.5%] who completed the standard AD, and 35 of 159 patients [22.0%] who completed the life-extending AD chose comfort care (P = .02), with patients not returning ADs coded as not selecting comfort care. In mITT analyses, median (interquartile range) hospital-free days among 168 patients assigned to comfort ADs and 159 patients assigned to life-extending default ADs were each noninferior to those among 165 patients assigned to standard ADs (standard AD: 486 [306-717] days; comfort AD: 554 [296-833] days; rate ratio, 1.05; 95% CI, 0.90-1.23; P < .001; life-extending AD: 550 [325-783] days; rate ratio, 1.03; 95% CI, 0.88-1.20; P < .001). There were no differences among groups in other secondary outcomes. Conclusions and Relevance: In this randomized clinical trial, default options in ADs altered the choices seriously ill patients made regarding their future care without changing clinical outcomes. Trial Registration: ClinicalTrials.gov Identifier: NCT02017548.