What is the hospital volume threshold to optimize inpatient complication rate after partial nephrectomy?

Objective: To find a cutoff of hospital volume for elective partial nephrectomy (PN) for kidney cancer that can minimize the inpatient morbidity of this procedure. Material and methods: Analyzing the National Inpatient sample, from 2008 to 2011, we selected 8,753 records of adult patients undergoing elective PN for nonmetastatic kidney cancer, representing an estimated 43,178 partial nephrectomies performed in the United States during this period. Of these, 2,187 (estimated 10,848) PNs were performed via the robotic approach. International Classification of Diseases, Ninth Revision, diagnosis and procedure codes were used to define complications. Logistic regression within generalized estimating equation framework, with restricted cubic splines was used to identify the relationship of any inpatient complications and major inpatient complications with annual hospital PN volume, after adjusting for demographic characteristics, insurance status, location, and comorbidities. A similar analysis was done for a subset of patients undergoing robot-assisted PN. Results: Overall, rate of any inpatient complication and major inpatient complications was 1,801/8,753 (20.6%) and 839/8,753 (9.6%), respectively. Median annual hospital volume was 27 cases (interquartile range: 11-64). Restricted cubic spline analysis revealed a significant inverse nonlinear association between annual hospital volume and any inpatient complications (P < 0.001). The odds of complications decreased with increasing annual hospital volume, with plateauing seen at 35 to 40 cases for both any inpatient complications and major inpatient complications. Analysis on a subset of robot-assisted PN revealed a similar inverse nonlinear relationship, with plateauing at 18 to 20 cases annually. Conclusion: There is an inverse nonlinear relationship of hospital volume with morbidity of PN, with a plateauing seen at 35 to 40 cases annually overall, and at 18 to 20 cases for robot-assisted PN. (C) 2018 Elsevier Inc. All rights reserved.