Hospital Volume, Length of Stay, and Readmission Rates in High-Risk Surgery

TLDR

Hospital volume‑based referral strategies have been promoted to reduce surgical mortality in high‑risk surgery. This study aimed to determine whether hospital volume also reduces resource use, specifically postoperative length of stay and 30‑day readmission rates, in 14 cardiovascular and cancer procedures. Using a retrospective analysis of 2.5 million Medicare beneficiaries from 1994‑1999, the authors applied regression models adjusted for age, gender, race, comorbidity, admission acuity, and socioeconomic status to assess the relationship between volume and resource use. Hospital volume was not consistently linked to length of stay or 30‑day readmission rates; only a few procedures showed volume‑dependent LOS differences, and no procedure’s readmission rate varied with volume.

Abstract

In Brief Objective Aimed at reducing surgical deaths, several recent initiatives have attempted to establish volume-based referral strategies in high-risk surgery. Although payers are leading the most visible of these efforts, it is unknown whether volume standards will also reduce resource use. Methods We studied postoperative length of stay and 30-day readmission rate after 14 cardiovascular and cancer procedures using the 1994-1999 national Medicare database (total n = 2.5 million). We used regression techniques to examine the relationship between length of stay, 30-day readmission, and hospital volume, adjusting for age, gender, race, comorbidity score, admission acuity, and mean social security income. Results Mean postoperative length of stay ranged from 3.4 days (carotid endarterectomy) to 19.6 days (esophagectomy). There was no consistent relationship between volume and mean length of stay; it significantly increased across volume strata for 7 of the 14 procedures and significantly decreased across volume strata for the other 7. Mean length of stay at very-low-volume and very-high-volume hospitals differed by more than 1 day for 6 procedures. Of these, the mean length of stay was shorter in high-volume hospitals for 3 procedures (pancreatic resection, esophagectomy, cystectomy), but longer for other procedures (aortic and mitral valve replacement, gastrectomy). The 30-day readmission rate also varied widely by procedure, ranging from 9.9% (nephrectomy) to 22.2% (mitral valve replacement). However, volume was not related to 30-day readmission rate with any procedure. Conclusion Although hospital volume may be an important predictor of operative mortality, it is not associated with resource use as reflected by length of stay or readmission rates. In this study based on the national Medicare population, we examined length of stay and 30-day readmission rates with 14 cardiovascular and cancer procedures. Hospital procedure volume was not consistently related to either measure.