Volume-outcome relationship of liver surgery: a nationwide analysis

Background Evidence for an association between hospital volume and outcomes for liver surgery is abundant. The current Dutch guideline requires a minimum volume of 20 annual procedures per centre. The aim of this study was to investigate the association between hospital volume and postoperative outcomes using data from the nationwide Dutch Hepato Biliary Audit. Methods This was a nationwide study in the Netherlands. All liver resections reported in the Dutch Hepato Biliary Audit between 2014 and 2017 were included. Annual centre volume was calculated and classified in categories of 20 procedures per year. Main outcomes were major morbidity (Clavien-Dindo grade IIIA or higher) and 30-day or in-hospital mortality. Results A total of 5590 liver resections were done across 34 centres with a median annual centre volume of 35 (i.q.r. 20-69) procedures. Overall major morbidity and mortality rates were 11 center dot 2 and 2 center dot 0 per cent respectively. The mortality rate was 1 center dot 9 per cent after resection for colorectal liver metastases (CRLMs), 1 center dot 2 per cent for non-CRLMs, 0 center dot 4 per cent for benign tumours, 4 center dot 9 per cent for hepatocellular carcinoma and 10 center dot 3 per cent for biliary tumours. Higher-volume centres performed more major liver resections, and more resections for hepatocellular carcinoma and biliary cancer. There was no association between hospital volume and either major morbidity or mortality in multivariable analysis, after adjustment for known risk factors for adverse events. Conclusion Hospital volume and postoperative outcomes were not associated.