Performance assessment using mixed effects models: a case study on coronary patient care

Provider profiling is the process of evaluation of the performance of hospitals, doctors and other medical practitioners in order to increase the quality of medical care. This paper reports statistical analyses carried out on data arising from a regular survey concerning patients admitted with an ST-elevation myocardial infarction diagnosis in one of a number of hospitals in the Milan area. The main aim is to determine process indicators to be used in health-care evaluation. Effective statistical support for clinical and organizational governance is obtained by analysing and modelling data from clinical registries. A grouping structure and a consequent ranking of hospitals is investigated, taking into account the fact that this kind of survey data are intrinsically grouped at first level by where patients are hospitalized.We compare three different techniques for hospital classification based, respectively, on: (a) traditional comparison of survival rates; (b) analysis of variance components in fitted generalized linear mixed effects models; and (c) non-parametric random effects estimation.