Surgery groups differed in adverse outcome probabilities and can be used to adjust hospital comparisons

Marang-van de Mheen, P.J.; Mertens, B.J.A.; van Houwelingen, H.C.; Kievit, J.

doi:10.1016/j.jclinepi.2004.03.013

« Previous Next »Journal of Clinical Epidemiology
Volume 58, Issue 1 , Pages 56-62, January 2005

Surgery groups differed in adverse outcome probabilities and can be used to adjust hospital comparisons

P.J. Marang-van de Mheen
- Association of Surgeons of the Netherlands, Utrecht, The Netherlands
- Department of Medical Decision Making, Leiden University Medical Center, J10-S, PO Box 9600, 2300 RC Leiden, The Netherlands
- Corresponding author. Tel.: +31-71-5264574; fax: +31-71-5266838.
B.J.A. Mertens
- Department of Medical Statistics, University of Leiden, Leiden, The Netherlands
H.C. van Houwelingen
- Department of Medical Statistics, University of Leiden, Leiden, The Netherlands
J. Kievit
- Association of Surgeons of the Netherlands, Utrecht, The Netherlands
- Department of Medical Decision Making, Leiden University Medical Center, J10-S, PO Box 9600, 2300 RC Leiden, The Netherlands
- Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands

Accepted 8 March 2004.

Abstract

Background and objective

In the Netherlands, all procedures in general surgery are categorized into 12 surgery groups by the Association of Surgeons of the Netherlands. The purpose of this study was to assess whether surgery groups differ in adverse outcome probabilities, to decide whether hospital comparisons on adverse outcomes should be adjusted for differences in surgery groups.

Methods

All surgical patients in one hospital discharged in 1997–1999 were included. Only the first operation during admission was included, with the assumption that successive operations were treatment of adverse outcomes. To avoid bias, only operations with procedures from the same surgery group were included. A total of 6,025 admissions were included and analyzed by a two-step multilevel analysis.

Results

Four surgery groups had fewer admissions with adverse outcomes than expected, and two groups had more. After adjustment for patient and operation characteristics, the remaining variance between surgery groups is still large. Similar results were found when differences in mortality were analyzed.