Patterns of comorbid inflammatory diseases in frail older women: the Women's Health and Aging Studies I and II.

BACKGROUND: Developing interventions to prevent frailty in older adults is a priority as it increases the risk for disability, institutionalization, and death. Single chronic inflammatory diseases are known to increase the risk of frailty. Identification of comorbid inflammatory diseases that synergistically might heighten this risk would provide further insight into therapeutic approaches to prevent frailty. The study aims were to characterize whether there are specific inflammatory disease pairs that are associated with frailty and to determine whether the risk of frailty is affected by synergistic interactions between these inflammatory diseases. METHODS: Data were from the Women's Health and Aging Studies I and II and complementary cohorts of community-dwelling women aged 70-79 years from Baltimore, Maryland (n = 620). Multivariable logistic regression analyses were performed to evaluate the relationships between these diseases and frailty. RESULTS: Among the frail (11.3%), 15.2% had both depressive symptoms and anemia and 14.5% had pulmonary disease and anemia. The risk of frailty was synergistically increased in those with depressive symptoms and anemia (adjusted risk ratios = 11.93, 95% confidence interval [CI] 4.10-34.76) and those with pulmonary disease and anemia (risk ratios = 5.57, 95% CI 2.14-14.48), compared with those without either disease in each pair. The attributable proportions of frail cases due to interaction between the diseases of each pair were 0.56 (95% CI 0.07-1.05) and 0.61 (95% CI 0.18-1.05), respectively. CONCLUSIONS: Synergistic interactions between specific inflammatory diseases may heighten the risk of frailty. These findings suggest that a common etiologic pathway may exist among co-occurring inflammatory diseases and that their improved comanagement may be an approach to reducing frailty.