Sex differences in the construct overlap of frailty and depression: evidence from the Health and Retirement Study.

OBJECTIVES

To determine the degree of diagnostic overlap between frailty and depression and to investigate whether sex differences in symptom endorsement influence this overlap.

DESIGN

Cross-sectional latent class analysis.

SETTING

Data were from the 2008 wave of the Health and Retirement Study, a nationally representative longitudinal survey of health characteristics of older adults.

PARTICIPANTS

Community-dwelling adults aged 65 and older completing a general health questionnaire and consenting to physical measurements (N = 3,665).

MEASUREMENTS

Frailty was measured using criteria developed in the Cardiovascular Health Study, and depressive symptoms were measured using the eight-item Center for Epidemiologic Studies Depression scale.

RESULTS

Frailty and depression were best modeled as two distinct but highly correlated constructs with three and four classes of symptom response, respectively. Measurement overlap was high in men and women. Approximately 73% of individuals with severe depressive symptoms and 86% with primarily somatic depressive symptoms were categorized as concurrently frail. The degree of construct overlap between depression and frailty did not significantly vary according to sex, but women were significantly more likely to endorse all frailty and depressive symptoms.

CONCLUSION

Measures of depression and frailty identify substantially overlapping populations of older men and women. More-frequent endorsement of depressive symptoms, but not differential endorsement of somatic symptoms, may contribute to the higher prevalence of frailty in women. The symptom of exhaustion is particularly important to the correlation between these two conditions. Findings will inform clinician and researcher efforts to refine the definition of geriatric syndromes such as frailty and to develop effective interventions.