Construct overlap between depression and frailty in later life: evidence from the health and retirement study

Background: In epidemiologic research, late-life depression and frailty are often conceptualized and modeled as independent constructs despite having shared risk factors and consequences. Ignoring the interrelationships between depression and frailty may lead to false inferences about the relative importance of these syndromes for morbidity, disability, and mortality. The goal of this study was to use confirmatory latent class analysis to examine the joint relationship between the constructs of depression and frailty among community-dwelling older adults. Method: Data come from the 2008 wave of the Health and Retirement Study, a nationally-representative sample of adults over the age of 50. Analysis is limited to participants 65 and older with complete data on depressive symptoms and frailty indicators (N = 3665). Depressive symptoms were indexed by the 8-item Centers for Epidemiologic Studies Depression (CES-D) scale, and frailty was indexed by modified Fried criteria (i.e., low weight, inactivity, slowness, exhaustion, and weakness). Latent class analysis was used to model the depression and frailty constructs, and latent Kappa coefficients were estimated from competing models to assess the chance-corrected agreement between depression and frailty. Results: Latent class analyses suggested that depression and frailty could best be modeled as distinct syndromes, each with 3 classes. In the joint modeling of depression and frailty latent constructs, 13.0 of participants were classified as high depressive symptoms, 19.0 as mild, and 68.0 as low depressive symptoms. Regarding frailty, 18.2 were classified as severely frail, 18.5 , as mild, and 63.3 with low frailty symptoms. A latent Kappa statistic representing chance-corrected agreement between depression and frailty indicated substantial construct overlap (?l: 0.56, 95 CI: 0.53 0.59). Conclusion: Findings suggest that late-life depression and frailty, as commonly defined in epidemiologic research, are substantially interrelated constructs and identify overlapping populations of older adults. Future research should explicitly examine this relationship to better understand both late-life depression and frailty, and to identify intervention strategies to delay or prevent functional decline in later life.

depression/Depressive Symptoms/Frail Elderly/DISABILITY/DISABILITY/MORBIDITY/Mortality/CES Depression Scale/CES Depression Scale

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