[The impact of the data collection method on the medico-economic classification of admissions for myocardial infarction at the public hospitals in Lyon].

The aim of the PMSI (Programme de Médicalisation du Système d'Information) is to describe the activity of hospitals for budget allocation. To control the quality of this information, the authors carried out a study comparing the classification in homogenous disease groups (HDG) obtained from the PMSI with that obtained from the epidemiological data base of the PRIMA trial for patients admitted to the Civil Hospitals of Lyon for myocardial infarction between September 1st 1993 and January 31st 1995. Six hundred and fifty standardised hospital summaries were reconstituted form PRIMA data and grouped using the GENRSA 3 software. Five hundred and forty-one of these hospital stays were found in the PMSI data base and grouped. The concordance not due to chance between the two classifications was then assessed by the global kappa coefficient. It was less than the 40% threshold under which concordance not due to chance is considered to be unlikely. The discordances were essentially due to the presence of an associated diagnosis classifying the hospital stay in the HDG corresponding to complicated myocardial infarction. The presence of a classifying associated diagnosis was observed significantly more often in the PRIMA than in the PMSI data base. This results in an underestimation of the hospital activity and could have important repercussions in terms of budget allocation.