[Reliability and validity of death certificates specifying oral cancer as cause of death in Teresina, Piauí State, Brazil, 2004-2005].

Brazilian health policy depends on the accuracy of data in the health information system. This study aimed to assess the reliability and validity of data on underlying cause of death due to a specific neoplasm in the Municipality of Teresina, Piauí State, Brazil, based on all the death certificates from 2004 and 2005 that reported oral cancer as the underlying cause of death (total of 23 death certificates). The death certificates were recoded for underlying cause of death by using a form targeted at collecting clinical and laboratory data to confirm the medical diagnosis on patient charts. Diagnosis was confirmed by histopathologic examination and clinical history. Simple agreement was 91.3%, kappa coefficient 0.84, and positive predictive value 90.9%. Based on the findings, the mortality statistics were valid and reliable. One limitation to this study was the possible underreporting of cases with oral cancer as the underlying cause of death, given that such data are not included in the mortality information system in Teresina.