More than a quarter of depressed older persons is physically frail. Understanding the associations between frailty and depression may help to improve treatment outcome for late-life depression. The aim of this study is to test whether physical frailty predicts the course of late-life depression.

A cohort study (N=285) of depressed older persons aged ≥60 years with two years follow-up. Depression was classified according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria at baseline and at two-year follow-up. Severity of depression was assessed with the sum score as well as subscale scores of the Inventory of Depressive Symptomatology (IDS) at six-month intervals. Physical frailty was defined as ≥3 out of 5 criteria (handgrip strength, weight loss, poor endurance, walking speed, low physical activity).

Frail patients were more severely depressed compared to their non-frail counterparts. Multivariable logistic regression showed that physical frailty at baseline was associated with depression at two years follow-up, adjusted for socio-demographics and lifestyle factors. Linear mixed models showed that improvement of mood symptoms over time was independent of frailty status, whereas frailty had a negative impact on the course of the somatic and motivational symptoms of depression.

The negative impact of physical frailty on the course of depression may point to the potential importance of incorporating multi-facetted interventions in the treatment of late-life depression. Further understanding of the mediating mechanisms underlying the association between frailty and depression may further guide the development of these interventions.