Accuracy of the Mortality Information System team in the specification of underlying cause of death in a State capital in southern Brazil

This cross-sectional study aimed to investigate the quality of data on underlying cause of death as completed on the death certificate by the attending physician, as well as the accuracy of the Mortality Information System (MIS) team in Porto Alegre, Rio Grande do Sul State, Brazil, in specification of the cause. 950 hospital deaths were investigated, using systematic sampling. A new death certificate (DC) was completed with data collected from hospital files, and was compared to the original DC and the MIS DC for underlying cause of death. Disagreement between the original DC and new DC occurred in 16.1% of cases. Of the 103 original DCs containing errors, the MIS identified 64.1%. Among those correctly completed, 195 were identified by the MIS as containing problems. Among the 261 selected and investigated by the MIS, there was agreement in modification of the underlying cause of death between the MIS and the search in 76.8% of cases, and a loss of opportunity for qualification in 23.2%. Among the 198 non-modified DCs, 5.1% should have been modified, and 94.9% were correctly maintained. The sensitivity of the MIS in the identification of problems with underlying cause of death was 64.1%, and specificity was 75.5%.