A Nationally Representative Study of Nonindex Hospital Readmissions following Radical Prostatectomy: Implications for Bundled Payment Models

Purpose: Implementing episode based payment models requires a detailed understanding of health care utilization throughout the 90-day postoperative episode. This includes nonindex hospital readmissions, which currently do not exist for patients treated with radical prostatectomy. We compared the causes, costs and predictors of index vs nonindex hospital readmissions after radical prostatectomy. Materials and Methods: We identified patients with prostate cancer who underwent radical prostatectomy from 2010 to 2014 in the Nationwide Readmissions Database. Sociodemographic factors, hospital costs and causes of 90-day readmissions were compared between index and nonindex hospital readmissions. Multivariable regression models were used to determine whether nonindex readmissions were more costly than index readmission for several causes of readmission and also to identify predictors of nonindex readmissions. Results: Of the 214,473 patients treated with radical prostatectomy 12,316 (5.7%) experienced a 90-day readmission and 4,283 (30.6%) had a nonindex readmission. Nonindex readmissions were more likely for complications which were cardiovascular specific (16.6% vs 10.3%) and nonradical prostatectomy specific (49.4% vs 32.8%, each p<0.01). On multivariable modeling readmission costs were significantly higher for nonindex vs index readmissions ($10,751 vs $10,113, p<0.01). Cardiovascular and electrolyte related nonindex readmissions ($12,995 vs $10,108, p<0.001, and $4,962 vs $3,179, p=0.01, respectively) were more expensive. Nonindex hospital readmission predictors included minimally invasive radical prostatectomy (OR 1.28, 95% CI 1.03-1.58), radical prostatectomy done at a high volume institution (OR 2.02, 95% CI 1.41-2.89) and residence in a more rural location (less than 50,000 population OR 1.68, 95% CI 1.21-2.35). Conclusions: In this nationally representative study nonindex hospital readmissions were associated with higher readmission costs, which were driven by differences in a small subset of readmissions. The benefits of undergoing radical prostatectomy at a high volume center should be carefully balanced with the increased odds of nonindex hospital readmissions and higher costs associated with such centers as regionalization continues.