Association Between Body Mass Index and Survival in Individuals on Hemodialysis

To analyze the effects of body mass index (BMI) on all-cause and cardiovascular mortality in individuals undergoing hemodialysis.

This retrospective cohort study analyzed sociodemographic, clinical, and nutritional data from 953 patients with chronic kidney disease on hemodialysis and linked to death records from the Brazilian Mortality Information System (2019-2022). Kaplan-Meier survival curves and the log-rank tests were used to compare BMI and age groups. The Cox regression model was applied to assess the simultaneous effects of age, sex, time since diagnosis, education, smoking, and BMI on mortality.

Individuals with normal BMI had greater survival, with significantly higher survival curves over time, especially among adults and the elderly, compared to other BMI categories. Overweight adults and older adults showed shorter survival. When evaluating the covariates, the category of those who had never smoked showed an association with a protective effect against the risk of death (P = .0239), indicating that people who had never smoked had a 38.4% reduction in the risk of death compared to the reference group (former smokers). And those with "more than 11 years of schooling" showed a 61.7% reduction in the risk of death (P = .0467).

Individuals on hemodialysis with a BMI in a normal state have greater survival, highlighting the importance of individualized interventions to improve the prognosis and quality of life of these individuals, taking into account nutritional status and sociodemographic factors.