Impact of anemia and cardiovascular disease on frailty status of community-dwelling older women: the Women's Health and Aging Studies I and II.

Background: The physiological basis of the geriatric syndrome of frailty, a clinical state of increased vulnerability to adverse outcomes such as disability and mortality, remains to be better characterized. We examined the cross-sectional relationship between hemoglobin (Hb) and a recently-validated measure of frailty in community-dwelling older women, and whether this relationship was modified by cardiovascular disease (CVD) status.

Methods: Data were pooled from women 70-80 years old participating in the Women's Health and Aging Studies I and II (Baltimore, MD, 1992-1996) with known frailty status and Hb > or = 10 g/dL (n = 670). Logistic regression was used to model the relationship between frailty and Hb, adjusting for demographics, major chronic diseases, and physiologic and functional impairments.

Results: Prevalence of frailty was 14%. Frailty risk was highest at the lowest Hb levels, and lowest at mid-normal Hb levels (e.g., 13-14 g/dL). Mildly low and low-normal Hb concentrations were independently associated with frailty. Compared to an Hb concentration equal to 13.5 g/dL, the adjusted odds of being frail were 1.9 (95% confidence interval: 1.1-3.4) and 1.5 (95% confidence interval: 1.0-2.1) times higher for Hb concentrations equal to 11.5 g/dL and 12 g/dL, respectively. A statistically significant (p <.05) multiplicative interaction between Hb level and CVD status with respect to frailty risk was observed.

Conclusion: In community-dwelling older women, mildly low and low-normal Hb levels were independently associated with increased frailty risk. This risk was synergistically modified by the presence of CVD. These results suggest that mild anemia, and even low-normal Hb levels are independent, potentially modifiable risk factors for frailty in community-dwelling older adults.