Mortality information system for identifying underreported cases of tuberculosis in Brazil

The aim of the study was to analyze the underreporting of deaths from tuberculosis (TB) in Brazil, as well as to assess the impact these cases would cause in the reporting rate and proportion of TB deaths in 2006. We analyzed the deaths recorded in the Mortality Information System (SIM) in 2006 and all reports of TB in Brazil during the 2001 to 2006 period. The variables used for the relationship were: report number, city and State of residence, patient name, date and year of birth, sex, mother's name and address. Six blocking steps were performed. Scores above 12.4 were considered pairs, and those below 9.7, doubtful pairs. After each step, we performed a manual review of doubtful pairs. The Reportable Disease Information System (Sinan) had 547,589 records. The SIM had 6,924 records, 39.3% (n = 2,727) of which were not found in Sinan during the period evaluated. We observed that 64.5% (2,707) of deaths were reported in 2006 and after analyzing the proportion of deaths underreported by region and federal units, we found that the highest percentage was in the Northern region, followed by the Southeast and Northeast. The addition of deaths that had not been reported to the Sinan database increased the reporting rate 3.7%. Regarding the proportion of deaths due to TB, such inclusion was responsible for a 60.7% increase in this indicator. The relationship between both databases seems to be an important strategy for improving the quality of the TB surveillance system.