Survival analysis and iniquities in older Brazilians: a six year follow up survey in São Paulo, Brazil

Background

In Brazil, the aging process is fast with consequences for health services. By 2025 the elders will be more than 30 million people, 15% of Brazilian population. This study analyzes inequalities associated with survival of elders in a six year follow-up in Sao Paulo, Brazil.

Methods

Data comes from a longitudinal survey – SABE Study (Health, Well Being and Aging) that began in 2000 with a sample of population aged 60+ living in São Paulo/Brazil (n=2,143 from a multi stage clustered sampling). A procedure with probability proportional to the size was carried out using census tracts with replacement. To achieve the desired oversampling for respondents aged 75+, additional households close to the selected census tracts were sampled. The second wave was done in 2006 when 1115 elders were re-interviewed. Descriptive statistics included tests for association using Rao Scott procedure with correction for sample-design. Multi variable analysis was done by adjusting Cox regressions with robust estimation, stratified by age and sex. Kaplan-Meier Survival Analysis was used to compare survival curves by social demographic conditions (sex, schooling, income, early conditions) and health (depression, comorbidities, disability, self-perceived health and falls).

Results

Mortality rate was 55.2/1000years for males and 34.0/1000years for females. The demographic variables associated with survival, besides age and gender, were: greater education (p <0.0000), higher income (p <0.0000) and urban origin for women (p = 0.015). The health related variables were self-reported better health (p <0.000 for women and p = 0.016 for men), no self-reported disease (p <0.000), depression (p = 0.035 for women) and no disability (p <0.000). Cox regression showed clearly a gradient of increasing mortality with the decrease in income. In Kaplan-Meier analysis, absence of disability makes the male curve higher than the female.

Conclusions

There are inequalities associated with lower survival. Public policies should take into account the needs of the elderly population to facilitate access to health care services and reduce inequities.