Size of the Adult HIV-Infected Population Adjusted for the Unreported AIDS Mortality in the Santa Catarina State, Brazil, 2008-2017

Abstract

Objective: To estimate the number of 15-79-year-old individuals infected with HIV in the Santa Catarina state, Brazil, during the period 2008-2017. Methods: Three official registers of the HIV-infected individuals were compiled: SINAN for the HIV/AIDS epidemiological surveillance, SIM for mortality and SISCEL for the HIV viral load and CD4/CD8 cell count. Their records were linked by a unique personal identifier. Capture-recapture estimates were obtained by log-linear modelling with both the main effects and interaction between the registers, adjusted for age, sex and period. An adjustment for underreporting of AIDS-related deaths used published data on ill-defined causes of death and AIDS mortality. Results: After data sorting, 67340 HIV/AIDS records were identified: 29734 (44.2%) by SINAN, 5540 (8.2%) by SIM and 32066 (47.6%) by SISCEL. After record linkage, the HIV population size was estimated at 45707, whereas the capture-recapture method added 44 individuals. The number of new HIV/AIDS notifications per year increased significantly in 2014-2017 compared to the period 2011-2013 among 15-34-year-old men and less so for older men and women. Including 1512 unreported AIDS-related deaths gave an estimated 47263 HIV-infected individuals with 95% confidence interval (CI) of 47245-47282 and corresponding incidence of 93 (95% CI 91-96) p/100000. Case ascertainment of 62.9%, 78.5% and 67.8% was estimated for SINAN, SIM and SISCEL, respectively. Conclusion: Three major HIV/AIDS registers in Brazil showed significant under-notification of the HIV/AIDS epidemiological surveillance amenable to significant improvement by routine record linkage.