Does the Obesity Survival Paradox of Dialysis Patients Differ with Age?

Abstract

Background: The obesity paradox of hemodialysis patients (the association between obesity and survival) could be modified by age. We hypothesize that whereas obesity associates with survival in elderly patients, it behaves as a mortality risk marker in younger individuals. Methods: Retrospective study of 2002-2010 adult incident hemodialysis to analyze the relationship between body mass index (BMI) and annual body weight changes with mortality in different age strata. Results: Included in the study were 6,290 individuals. A progressive decrease in mortality was associated with increasing BMI ranges. Both annual body weight gains and losses were associated with mortality. Similar results were observed in elderly individuals, but in the BMI values of young patients, there were no significant differences in mortality. Conclusion: There is a survival benefit with increasing BMI in patients overall. However, while these results persist in patients >65 years, in young people there are no changes in mortality. Patients with the highest inter-annual variability in weight have an increased risk.