Process of care partly explains the variation in mortality between hospitals after peripheral vascular surgery

The aim of this study is to investigate whether variation in mortality at hospital level reflects differences in quality of care of peripheral vascular surgery patients.

Observational study.

In 11 hospitals in the Netherlands, 711 consecutive vascular surgery patients were enrolled.

Multilevel logistic regression models were used to relate patient characteristics, structure and process of care to mortality at 1 year. The models were constructed by consecutively adding age, sex and Lee index, then remaining risk factors, followed by structural measures for quality of care and finally, selected process of care parameters.

Total 1-year mortality was 11%, ranging from 6% to 26% in different hospitals. Large differences in patient characteristics and quality indicators were observed between hospitals (e.g., age>70 years: 28-58%; beta-blocker therapy: 39-87%). Adjusted analyses showed that a large part of variation in mortality was explained by age, sex and the Lee index (Akaike's information criterion (AIC)=59, p<0.001). Another substantial part of the variation was explained by process of care (AIC=5, p=0.001).

Differences between hospitals exist in patient characteristics, structure of care, process of care and mortality. Even after adjusting for the patient population at risk, a substantial part of the variation in mortality can be explained by differences in process measures of quality of care.