Prevalence and incidence of decreased glomerular filtration rate and its variation over 6 years: Cohort study SABE...

The aging process and the rising prevalence of Chronic Noncommunicable Diseases (NCDs) contribute to the decline in kidney function among elderly individuals. The aim of this research was to assess prevalence and incidence of decreased glomerular filtration rate (GFR) (GFR <60mL/min/1.73m2) over six-year period in elderly residents of São Paulo. This study relied on data from 2010 and 2016 waves of the cohort SABE Study - Health, Wellbeing, and Aging, with a probabilistic and representative sample of elderly individuals residing in São Paulo. GFR was calculated using the 2021 Chronic Kidney Disease Epidemiology Collaboration creatinine (CKD-EPI) equation. Categorical variables were analyzed using chi-square test with Rao-Scott correction, and weighted means and standard errors were calculated for continuous variables. Logistic and linear regression models were constructed to analyse the data. Statistical analyses accounted for sample weights to ensure population representativeness. The prevalence of decreased GFR in 2010 was 17.3%, with mean GFR of 75.6 mL/min/1.73m2 (SE = 0.5). The incidence of decreased GFR between 2010 and 2016 was 14.9%, equivalent to an annual incidence of 2.5%. This incidence was associated with older age, hypertension, self-perceived fair/poor/very poor health, and greater number of comorbidities associated. Over the study period, 68.1% of the elderly participants experienced deterioration in GFR, with an average decline of 1 mL/min/1.73m2 each year. Renal function decline often occurs without noticeable symptoms, and the high prevalence of comorbidities contributes to the worsening of GFR. Therefore, monitoring renal function in the elderly is crucial for effectively managing the health of this population.