[Probable cause of death after reclassification of ill-defined causes on hospital admissions forms in the Unified National Health System, Rio de Janeiro, Brazil].

This article describes the clinical and socio-demographic characteristics of deaths from ill-defined causes in the State of Rio de Janeiro, Brazil, in 1998, and reclassifies the groups of probable causes based on data from death certificates in the Mortality Information System and the Hospital Information System of the Unified National Health System (SIH-SUS) for 1997-98. Reclassification required a random sample of defined causes from the SIH-SUS. The technique used was probabilistic relationship of records. As compared to deaths with defined causes, in those with ill-defined causes the individuals were predominantly non-white, had less schooling, had died in Greater Metropolitan Rio de Janeiro, were less likely to have been hospitalized in the SUS, and were more likely to have died at home and without medical care. It was possible to reclassify 20% of deaths with ill-defined causes. Reclassification had a minor impact on proportional mortality, due to the size of this group (10% of the deaths). However, if the results could be applied to all deaths with ill-defined causes, the impact might be greater on proportional mortality.