[Grouping of the International Classification of Diseases for analysis of hospital readmissions].

ICD chapters and three-digit categories are not always appropriate for epidemiological analysis; the former are too generic and the latter too numerous. When the epidemiological focus is not on a specific clinical diagnosis, an intermediate grouping proposal between these two possibilities becomes necessary. Such proposals are not frequent in the literature. We used a two-stage grouping proposal based on hospital admissions volume, internal clinical coherence in each group, and the results of a Cox multivariate model for real data. As a result, we obtained 26 groups for adults and 19 groups for children, among which we chose hernia as the reference category for adults and appendiceal disease for children. The grouping proved adequate for the analysis of readmissions in a large Brazilian general hospital. Procedures similar to those described in this research report can be used to analyze other health problems.