Abstract: PD14-07
Sources of Funding: Urology Care Foundation Research Scholars Award, Society of Urologic Oncology

Introduction

Readmissions have become a focus of quality improvement as policy makers emphasize the delivery of value-based care. Vertically integrated health systems have the greatest ability and incentive to minimize unplanned readmissions. We compare 30-day readmission rates for patients undergoing urologic oncology surgery between three types of health systems in California: an integrated health system (IHS), safety-net hospitals (SNH), and traditional hospital systems (non-SNH).

Methods

We used California Office of Statewide Health Planning and Development data from 2007-2011, including all patients in California undergoing radical prostatectomy (RP) for prostate cancer, radical cystectomy (RC) for bladder cancer, and partial nephrectomy (PN) or radical nephrectomy (RN) for kidney cancer. We compared risk adjusted readmission rates using Medicare Hospital Readmissions Reduction Program models with the addition of patient socioeconomic status (SES). A separate model was used for each cohort. Comorbidity was assigned using the Elixhauser Index. Patient SES was derived from a Census based neighborhood score at the ZIP code level.

Results

Overall, 19-21% of RP, RC, PN, and RN were performed at an IHS hospital; 5-9% at a SNH. There were 1,185 readmissions in RP, 999 in RC, 537 in PN, and 1,107 in RN. Unadjusted 30-day readmissions at IHS hospitals were 3.6% in compared to 3.1% in SNH and 3.3% in non-SNH, 26.7% for RC compared with 25.3% for non-SNH and 25.2% for SNH, 8.4% for PN compared with 9.6% for non-SNH and 10.7% for SNH, and 8.0% for RN compared with 8.3% for non-SNH and 9.5% for SNH (all non-significant). In multivariate models (Table), higher patient comorbidity was associated with increased readmission rates across all 4 cohorts. Additional factors associated with readmissions included female sex and open surgical approach in PN, and age, open approach, distance from hospital, and urban status in RN, and age in RP. Across all 4 surgical cohorts, hospital system type was not associated with readmissions.

Conclusions

Irrespective of health system structure, readmissions among urologic oncology patients are driven by patient characteristics, such as comorbidity, and not hospital type or health system structure. This has important implications for the delivery of value-based care as hospitals become more vertically integrated to improve outcomes.

Funding

Urology Care Foundation Research Scholars Award, Society of Urologic Oncology