Information–processing methods for mortality surveillance in the presence of varying levels of completeness and ill–defined codes of causes of death – the case of Brazil

Background: The World Health Organization has developed proposals on how efforts to reduce non–communicable diseases (NCD) in low– and middle–income countries may be monitored over time. One of the proposed indicators is the unconditional probability of death between the ages of 30 and 70 from any of the four main groups of non–communicable diseases – cardiovascular disease, cancer, chronic respiratory disease, and diabetes. Our objective is to describe information–processing methods developed to facilitate this monitoring of mortality over time for Brazil. Methods: We developed an IPython Notebook which incorporates mortality records, population sizes, estimates of sub notification, redistribution of ill–defined causes of death, international disease codes, and world standard population weights for five–year age group, gender, state, and year strata. The approach permits flexibility in the incorporation of different estimates of sub–notification and ill–defined causes of death. The main output is a “Basic Sheet”, where each line provides corrected deaths by disease categories and denominators for a given stratum. This sheet is then used to generate desired statistics. Results: This collection of shareable computer code and data organizes the approach necessary for calculations, making the data available to interested parties for the remaining relatively simple calculations. The mortality statistic suggested by the World Health Organization is derived from this sheet. Conclusions: The approach developed is an additional step toward rapid and accurate reporting of Brazilian NCD mortality data. The code is available and may be adapted by others facing similar tasks.