The relationship between anemia, hemoglobin concentration and frailty in Brazilian older adults

Objective: to explore the relationship between anemia, hemoglobin concentration and frailty syndrome in older adults. Research Methods and Procedures: This was a cross-sectional population-based study, with adults ≥60 years (n=1,256) from the third wave of the SABE Cohort Study (Health, Well-being and Aging) conducted in 2010 in São Paulo, Brazil. Frailty syndrome was evaluated according to Fried´s phenotype. Anemia was defined using the WHO criteria (hemoglobin concentration <12 g/dL for women and <13 g/dL for men). Four approaches were used to verify the associations between anemia, hemoglobin concentration and frailty status or number of frailty criteria. We used logistic regression and Poisson regression in the analyses, and they were adjusted in three hierarchical models using three blocks of variables: basic characteristics; clinical characteristics; cognitive status. Results: Mean hemoglobin concentration was significantly lower in frail elderly (13.3g/dL, versus 14.3g/dL in non-frail; p<0.001). Prevalence of anemia was also significantly higher in frail when compared to non-frail elderly (24.2% and 3.8%; p<0.001). Anemia was significantly associated to low physical activity, weakness and slowness. In the fully adjusted regression models, anemia was strongly associated to frailty (OR=3.27, 95%IC=1.89,5.65; p<0.001), and lower levels of hemoglobin were associated to higher number of frailty criteria. Conclusions: We found important associations between anemia, hemoglobin concentration and frailty; anemic older adults were more likely to be frail, and lower levels of hemoglobin were associated to higher number of frailty criteria showing a clear dose-response effect.