ABC | Volume 115, Nº2, August 2020

Original Article Malta et al. Cardiovascular Disease Mortality in SIM and GBD Arq Bras Cardiol. 2020; 115(2):152-160 Figure 2 - Flowchart of the estimates of the Crude and Corrected Information System on Mortality and the Global Burden of Diseases Study, methods for correction and population used, for absolute numbers and mortality rates. CVD: Cardiovascular Diseases; IBGE: Brazilian Institute of Geography and Statistics; SIM: Brazilian Information System on Mortality; GBD: Global Burden of Diseases Study; IDCD: Ill-Defined Causes of Death. Crude SIM Corrected SIM GBD 2017 estimates CVD: underlying causes I00-I99 (ICD-10) SIM Population estimated: 2000 (IBGE 2013) to 2017 (IBGE 2018) Absent data: proportional CVD: I00-I99 Correction for underreporting GBD 2017 Proportional redistribution of IDCD// (Chap. XVIII) Population estimated: 2000 (IBGE 2013) to 2017 (IBGE 2018) Cardiovascular estimates of GBD 2017: corrections according to the GBD methodology, population estimates of GBD generated by the Crude SIM were age-standardized, no other correction being applied. The estimates generated by the Corrected SIM were age-standardized and corrected as follows: for underreporting, by using the GBD methodology; for the deaths lacking information on age and sex, by using the proportional redistribution of these deaths; and for the ill-defined causes of death, by using the proportional redistribution of these causes in the groups of cardiovascular causes and the other ICD-10 chapters. 4 The GBD 2017 estimates were extracted from the Institute for Health Metrics and Evaluation (IHME) database, underwent the previously described corrections, such as for underreporting, GC, and ill-defined causes of death, and were detailed in previous publications. 7,8,10 Data from the Crude SIMand Corrected SIMwere compared with the estimates of the GBD Study 2017, which also uses SIM data as a source, both by using the 2000-2017 historical series of the total of deaths and absolute numbers of the diseases listed in the ICD-10 IX chapter , and the age-standardized rates of the three estimates. To calculate the rates in the Crude SIM and the Corrected SIM, the updated population estimates generated by the Brazilian Institute of Geography and Statistics (IBGE) were used as denominator. 11 However, that IBGE estimate only provides data from2010 onwards; thus, two interpolations were applied: one with data from the year 2000 of the 2013 version made available by IBGE, 12 and another interpolation with data from the year 2010 of the current version made available in 2018. 11 The standard population used to adjust the age- standardized rates, through the direct method, was the world population of the GBD Study. 7 To calculate the rates, the GBD Study considers its own population estimates (Source GBD). All three estimates were analyzed for the ICD-10 chapter IX codes (diseases of the circulatory system - I00-I99) from 2000 to 2017. Figure 2 shows the flowchart used to compare the three estimates, regarding the absolute numbers of deaths and mortality rates for Brazil, its states, and Federal District. The analyses were performed using Stata Statistical Software: Release 14. College Station, TX: StataCorp LP. Results Figure 1 shows the proportion of ill-defined causes of death in relation to the total number of deaths in Brazil from 2000 to 2017. That proportion was 14.3% in 2000 and decreased over time, more abruptly from 2005 onward, reaching 5.5% in 2017. Table 1 shows that a large number of deaths with underlying causes classified as ICD-10 chapter IX codes constituted GC, as by the definition of GC in the GBD Study 2017, and that proportion was 42.1% in 2017. In addition, Table 1 shows that the number of GC decreased slowly over the years, indicating an improvement in the quality of the definition of the ICD-10 chapter IX causes of death. The GBD Study redistributes the GC in its estimates. The absolute numbers of deaths due to CVD and standardized mortality rates of the Crude SIM, the Corrected SIM, and the GBD Study 2017 estimates were analyzed. Figure 3 depicts the absolute number of deaths due to CVD for the three estimates, with a similar increase for all three methods. The SIM registered approximately 261,000 deaths in 2000, reaching 359,000 deaths in 2017. After data correction, the SIM records ranged from 324,000 in 2000 to 397,000 in 2017. The GBD 2017 estimates increased from 292,000 deaths to 388,000 deaths in those same years. The CVD mortality rates decreased in the period analyzed (Figure 4). The Crude SIM rates decreased from 211.7 to 155.1 deaths per 100,000 inhabitants, while the Corrected SIM 154