Rachel R Kelz

Biographic Data

ID5538145
NAMERachel R Kelz
GIVEN NAMESRachel R
FAMILY NAMEKelz
SIGNATUREKELZ R R
AFFILIATIONSLeonard Davis Institute of Health Economics, University of Pennsylvania
ORCID0000-0001-6635-5961
VERIFIEDNo
TOTAL WORKS7
TOTAL CITATIONS0
AUTHOR COUNT7
EDITOR COUNT0
FIRST PUBLICATION YEAR2005
LATEST PUBLICATION YEAR2023
H-INDEX0

  • The Safety of Performing Surgery at Ambulatory Surgery Centers Versus Hospital Outpatient Departments in Older Patients With or Without Multimorbidity

    Jeffrey H Silber, Paul R Rosenbaum et al.ARTICLEMedical Care2023References: 33

    BACKGROUND: Surgery for older Americans is increasingly being performed at ambulatory surgery centers (ASCs) rather than hospital outpatient departments (HOPDs), while rates of multimorbidity have increased. OBJECTIVE: To determine whether there are differential outcomes in older patients undergoing surgical procedures at ASCs versus HOPDs. RESEARCH DESIGN: Matched cohort study. SUBJECTS: Of Medicare patients, 30,958 were treated in 2018 and 2019…

  • Conditional Effects of Race on Operative and Nonoperative Outcomes of Emergency General Surgery Conditions

    Sanford E Roberts, Claire B Rosen et al.ARTICLEMedical Care2023References: 33

    INTRODUCTION: Many emergency general surgery (EGS) conditions can be managed both operatively or nonoperatively; however, it is unknown whether the decision to operate affects Black and White patients differentially. METHODS: We identified a nationwide cohort of Black and White Medicare beneficiaries, hospitalized for common EGS conditions from July 2015 to June 2018. Using near-far matching to adjust for measurable confounding and an instrumenta…

  • Multimorbidity Confers Greater Risk for Older Patients in Emergency General Surgery Than the Presence of Multiple Comorbidities: A Retrospective Observational Study

    Claire B Rosen, Chris Wirtalla et al.ARTICLEMedical Care2022References: 33

    BACKGROUND: Little is known about the impact of multimorbidity on outcomes for older emergency general surgery patients. OBJECTIVE: The aim was to understand whether having multiple comorbidities confers the same amount of risk as specific combinations of comorbidities (multimorbidity) for a patient undergoing emergency general surgery. RESEARCH DESIGN: Retrospective observational study using state discharge data. SUBJECTS: Medicare beneficiaries…

  • Falsification Tests for Instrumental Variable Designs With an Application to Tendency to Operate

    Luke Keele, QINGYUAN ZHAO et al.ARTICLEMedical Care2019References: 18

    BACKGROUND: Instrumental variable (IV) methods are becoming an increasingly important tool in health services research as they can provide consistent estimates of causal effects in the presence of unobserved confounding. However, investigators must provide justifications that the IV is independent with any unmeasured confounder and its effect on the outcome occurs only through receipt of the exposure. These assumptions, while plausible in some co…

  • Defining Multimorbidity in Older Surgical Patients

    Jeffrey H Silber, Joseph G Reiter et al.ARTICLEMedical Care2018References: 43

    BACKGROUND: There are numerous definitions of multimorbidity (MM). None systematically examines specific comorbidity combinations accounting for multiple testing when exploring large datasets. OBJECTIVES: Develop and validate a list of all single, double, and triple comorbidity combinations, with each individual qualifying comorbidity set (QCS) more than doubling the odds of mortality versus its reference population. Patients with at least 1 QCS …

  • Examining Causes of Racial Disparities in General Surgical Mortality: Hospital Quality Versus Patient Risk

    Jeffrey H Silber, Paul R Rosenbaum et al.ARTICLEMedical Care2015References: 38

    BACKGROUND: Racial disparities in general surgical outcomes are known to exist but not well understood. OBJECTIVES: To determine if black-white disparities in general surgery mortality for Medicare patients are attributable to poorer health status among blacks on admission or differences in the quality of care provided by the admitting hospitals. RESEARCH DESIGN: Matched cohort study using Tapered Multivariate Matching. SUBJECTS: All black elderl…

  • Changes in Prognosis After the First Postoperative Complication

    Jeffrey H Silber, Paul R Rosenbaum et al.ARTICLEMedical Care2005References: 17

    BACKGROUND: Postoperative complications are common in the Medicare population, yet no study has formally quantified the change in prognosis that occurs after a broad range of first complications. OBJECTIVE: We sought to estimate the relative severity of 24 first postoperative complications. RESEARCH DESIGN: We undertook a multivariate matched, population-based, case-control study of death after surgery in a sample of 1362 Pennsylvania Medicare pa…