Case-mix adjustment to compare nationwide hospital performances after resection of colorectal liver metastases

A.K.E. Elfrink*, E.W. van Zwet, R.J. Swijnenburg, M. den Dulk, P.B. van den Boezem, J.S.D. Mieog, W.W. te Riele, G.A. Patijn, W.K.G. Leclercq, D.J. Lips, A.M. Rijken, C. Verhoef, K.F.D. Kuhlmann, C.I. Buis, K. Bosscha, E.J.T. Belt, M. Vermaas, N.T. van Heek, S.J. Oosterling, H. TorrengaH.H. Eker, E.C.J. Consten, H.A. Marsman, M.W.J.M. Wouters, N.F.M. Kok, D.J. Grunhagen, J.M. Klaase, Dutch Hepato Biliary Audit Group

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

10 Citations (Web of Science)


Background: Differences in patient demographics and disease burden can influence comparison of hospital performances. This study aimed to provide a case-mix model to compare short-term postoperative outcomes for patients undergoing liver resection for colorectal liver metastases (CRLM).

Methods: This retrospective, population-based study included all patients who underwent liver resection for CRLM between 2014 and 2018 in the Netherlands. Variation in case-mix variables between hospitals and influence on postoperative outcomes was assessed using multivariable logistic regression. Primary outcomes were 30-day major morbidity and 30-day mortality. Validation of results was performed on the data from 2019.

Results: In total, 4639 patients were included in 28 hospitals. Major morbidity was 6.2% and mortality was 1.4%. Uncorrected major morbidity ranged from 3.3% to 13.7% and mortality ranged from 0.0% to 5.0%. between hospitals. Significant differences between hospitals were observed for age higher than 80 (0.0%-17.1%, p < 0.001), ASA 3 or higher (3.3%-36.3%, p < 0.001), histopathological parenchymal liver disease (0.0%-47.1%, p < 0.001), history of liver resection (8.1%-36.3%, p < 0.001), major liver resection (6.7%-38.0%, p < 0.001) and synchronous metastases (35.5%-62.1%, p < 0.001). Expected 30-day major morbidity between hospitals ranged from 6.4% to 11.9% and expected 30-day mortality ranged from 0.6% to 2.9%. After case-mix correction no significant outliers concerning major morbidity and mortality remained. Validation on patients who underwent liver resection for CRLM in 2019 affirmed these outcomes.

Conclusion: Case-mix adjustment is a prerequisite to allow for institutional comparison of short-term postoperative outcomes after liver resection for CRLM. (C) 2020 University Medical Center Groningen. Published by Elsevier Ltd.

Original languageEnglish
Pages (from-to)649-659
Number of pages11
JournalEuropean Journal of Surgical Oncology
Issue number3
Publication statusPublished - 1 Mar 2021

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