Low-Volume Elective Surgery and Outcomes in Medicare Beneficiaries Treated at Hospital Networks

Abstract

Minimum volume standards have been advocated as a strategy to improve outcomes for certain surgical procedures. Hospital networks could avoid low-volume surgery by consolidating cases within network hospitals that meet volume standards, thus optimizing outcomes while retaining cases and revenue. The rates of compliance with volume standards among hospital networks and the association of volume standards with outcomes at these hospitals remain unknown. To quantify low-volume surgery and associated outcomes within hospital networks. This cross-sectional study used Medicare Provider Analysis and Review data to examine fee-for-service beneficiaries aged 66 to 99 years who underwent 1 of 10 elective surgical procedures (abdominal aortic aneurysm repair, carotid endarterectomy, mitral valve repair, hip or knee replacement, bariatric surgery, or resection for lung, esophageal, pancreatic, or rectal cancers) in a network hospital from 2016 to 2018. Hospital volume for each procedure (calculated with the use of the National Inpatient Sample) was compared with yearly hospital volume standards for that procedure recommended by The Leapfrog Group. Networks were then categorized into 4 groups according to whether or not that hospital or another hospital in the network met low-volume standards for that procedure. Data were analyzed from February to June 2023. Receipt of surgery in a low-volume hospital within a network. Primary outcomes were postoperative complications, 30-day readmission, and 30-day mortality, stratified by the volume status of the hospital and network type. The secondary outcome was the availability of a different high-volume hospital within the same network or outside the network and its proximity to the patient (based on hospital referral region and zip code). In all, data were analyzed for 950 079 Medicare fee-for-service beneficiaries (mean [SD] age, 74.4 [6.5] years; 621 138 females [59.2%] and 427 931 males [40.8%]) who underwent 1 049 069 procedures at 2469 hospitals within 382 networks. Of these networks, 380 (99.5%) had at least 1 low-volume hospital performing the elective procedure of interest. In 35 137 of 44 011 procedures (79.8%) that were performed at low-volume hospitals, there was a hospital that met volume standards within the same network and hospital referral region located a median (IQR) distance of 29 (12-60) miles from the patient's home. Across hospital networks, there was 43-fold variation in rates of low-volume surgery among the procedures studied (from 1.5% of carotid endarterectomies to 65.0% of esophagectomies). In adjusted analyses, postoperative outcomes were inferior at low-volume hospitals compared with hospitals meeting volume standards, with a 30-day mortality of 8.1% at low-volume hospitals vs 5.5% at hospitals that met volume standards (adjusted odds ratio, 0.67 [95% CI, 0.61-0.73]; P < .001). Findings of this study suggest that most US hospital networks had hospitals performing low-volume surgery that is associated with inferior surgical outcomes despite availability of a different in-network hospital that met volume standards within a median of 29 miles for the vast majority of patients. Strategies are needed to help patients access high-quality care within their networks, including avoidance of elective surgery at low-volume hospitals. Avoidance of low-volume surgery could be considered a process measure that reflects attention to quality within hospital networks.