Course of depression and mortality among older primary care patients

Abstract

Context: : Depression is a treatable illness that disproportionately places older adults at increased risk for mortality.

Objective: : We sought to examine whether there are patterns of course of depression severity among older primary care patients that are associated with increased risk for mortality.

Design and setting: : Our study was a secondary analysis of data from a practice-based randomized controlled trial within 20 primary care practices located in greater New York City, Philadelphia, and Pittsburgh.

Participants: : The study sample consisted of 599 adults aged 60 years and older recruited from primary care settings. Participants were identified though a two-stage, age-stratified (60-74 years; older than 75 years) depression screening of randomly sampled patients. Severity of depression was assessed using the 24-item Hamilton Depression Rating Scale (HDRS).

Measurements: : Longitudinal analysis via growth curve mixture modeling was carried out to classify patterns of course of depression severity across 12 months. Vital status at 5 years was ascertained via the National Death Index Plus.

Results: : Three patterns of change in course of depression severity over 12 months were identified: 1) persistent depressive symptoms, 2) high but declining depressive symptoms, 3) low and declining depressive symptoms. After a median follow-up of 52.0 months, 114 patients had died. Patients with persistent depressive symptoms were more likely to have died compared with patients with a course of high but declining depressive symptoms (adjusted hazard ratio 2.32, 95% confidence interval [1.15-4.69]).

Conclusions: : Persistent depressive symptoms signaled increased risk of dying in older primary care patients, even after adjustment for potentially influential characteristics such as age, smoking status, and medical comorbidity.

Figure 1

Mean observed Hamilton Depression Rating Scales across time stratified on the three patterns of depressive symptoms (n=597). Note: Data gathered from the PROSPECT study. HDRS = Hamilton Depression Rating Scale.

Figure 2

Survival curves for the three patterns of depressive symptoms (n=597). Note: Data gathered from the PROSPECT study.