Reliability of death certificates in the study of stroke mortality. A retrospective study in a Sicilian municipality.

The subjects who died in the Sicilian municipality of Riposto between 1985 and 1992, and whose death certificates reported diagnoses of cerebrovascular disease, were re-evaluated with the aim of verifying the reliability of the certificates themselves. The relatives of the deceased were interviewed to confirm or exclude stroke, and about 35% of the cases proved to be false positives. Among the causes reported on the death certificates, "stroke", "cerebral hemorrhage" and "cerebral thrombosis" presented the smallest number of false positives. Our results show that the sensitivity and specificity of the death certificates was poor, and there would also seem to be a large number of false negatives. However, the official mortality rates for cerebrovascular disease are probably not very far from the truth.