Minimum volume standards in German hospitals: do they get along with procedure centralization? A retrospective longitudinal data analysis

BACKGROUND: Compliance with minimum volume standards for specific procedures serves as a criterion for high-quality patient care. International experiences report a centralization of the respective procedures. In Germany, minimum volume standards for hospitals were introduced in 2004 for 5 procedures (complex esophageal and pancreatic interventions; liver, kidney and stem cell transplantations), in 2006 total knee replacement was added. This study explores whether any centralization is discernible for these procedures in Germany. METHODS: A retrospective longitudinal analysis of secondary data serves to determine a possible centralization of procedures from the system perspective. Centralization means that over time, fewer hospitals perform the respective procedure, the case volume in high-volume hospitals increases together with their percentage of the annual total case volume, and the case volume in low-volume hospitals decreases together with their percentage of the annual total case volume. Using data from the mandatory hospital quality reports for the years 2006, 2008 and 2010 we performed Kruskal Wallis and chi-square tests to evaluate potential centralization effects. RESULTS: No centralization was found for any of the six types of interventions over the period from 2006 to 2010. The annual case volume and the number of hospitals performing interventions rose at differing rates over the 5-year period depending on the type of intervention. Seven percent of esophagectomies and 14 % of pancreatectomies are still performed in hospitals with less than 10 interventions per year. CONCLUSIONS: For the purpose of further centralization of interventions it will be necessary to first analyze and then appropriately address the reasons for non-compliance from the hospital and patient perspective.