Association between hospital volume and outcomes of elderly and non-elderly patients with acute biliary diseases: A national administrative database analysis

Aim: This study aimed to investigate the relationship between hospital volume and clinical outcomes of elderly and non-elderly patients with acute biliary diseases using data from a national administrative database. Methods: Overall, 26720 elderly and 33774 non-elderly patients with acute biliary diseases were referred to 820 hospitals in Japan. Hospital volume was categorized into three groups based on the case numbers during the study period: low-volume, medium-volume and high-volume. We compared the risk-adjusted length of stay (LOS) and in-hospital mortality in relation to hospital volume. These analyses were stratified according to the presence of invasive treatments for acute biliary diseases. Results: Multiple linear regression analyses showed that increased hospital volume was significantly associated with shorter LOS in both elderly and non-elderly patients with and without invasive treatments. Increased hospital volume was significantly associated with decreased relative risk of in-hospital mortality in elderly patients. The odds ratio for high-volume hospitals was 0.672 in elderly patients without invasive treatments (95% confidence interval [CI] 0.533-0.847, P=0.001) and 0.715 in those with invasive treatments (95% C, 0.566-0.904, P=0.005). However, no significant differences for in-hospital mortality were seen in non-elderly patients with and without invasive treatments. Conclusion: This study has highlighted that higher volume hospitals significantly reduced LOS and in-hospital mortality for elderly patients with acute biliary diseases, but not non-elderly patients. The current results are of value for elderly healthcare policy decision-making, and highlight the need for further studies into the quality of care for elderly patients. Geriatr Gerontol Int 2013; 13: 731-740.