Long term effect of depression care management on mortality in older adults: follow-up of cluster randomized clinical trial in primary care

Abstract

Objective: To investigate whether an intervention to improve treatment of depression in older adults in primary care modified the increased risk of death associated with depression.

Design: Long term follow-up of multi-site practice randomized controlled trial (PROSPECT-Prevention of Suicide in Primary Care Elderly: Collaborative Trial).

Setting: 20 primary care practices in New York City, Philadelphia, and Pittsburgh, USA, randomized to intervention or usual care.

Participants: 1226 participants identified between May 1999 and August 2001 through a two stage, age stratified (60-74; ≥ 75 years) depression screening of randomly sampled patients; enrollment included patients who screened positive and a random sample of patients who screened negative.

Intervention: For two years, a depression care manager worked with primary care physicians in intervention practices to provide algorithm based care for depression, offering psychotherapy, increasing antidepressant dose if indicated, and monitoring symptoms, adverse effects of drugs, and adherence to treatment. This paper reports the long term follow-up.

Main outcome measure: Mortality risk based on a median follow-up of 98 (range 0.8-116.4) months through 2008.

Results: In baseline clinical interviews, 396 people were classified as having major depression, 203 had clinically significant minor depression, and 627 did not meet criteria for depression. At follow-up, 405 patients had died. Patients with major depression in usual care were more likely to die than were those without depression (hazard ratio 1.90, 95% confidence interval 1.57 to 2.31). In contrast, patients with major depression in intervention practices were at no greater risk than were people without depression (hazard ratio 1.09, 0.83 to 1.44). Patients with major depression in intervention practices, relative to usual care, were 24% less likely to have died (hazard ratio 0.76, 0.57 to 1.00; P=0.05). Preliminary data on cause of death are provided. No significant effect on mortality was found for minor depression.

Conclusions: Older adults with major depression in practices provided with additional resources to intensively manage depression had a mortality risk lower than that observed in usual care and similar to older adults without depression.

Trial registration: Clinical trials NCT00000367.

Fig 1 Flow chart for mortality follow-up of PROSPECT patients. CES-D=Centers for Epidemiologic Studies depression scale

Fig 2 Survival probability among people with no depression or major depression in practices randomized to usual care (top panel) or to intervention (bottom panel). Data from PROSPECT (1999-2008)

Fig 3 Adjusted hazard ratios (95% CI) for specific causes of death comparing major depression with no depression within intervention or usual care practices. Data from PROSPECT (1999-2008). Hazard ratios are from Cox proportional hazards models. Adjusted models included terms for baseline age, sex, education, marital status, smoking, cardiovascular disease, stroke, diabetes, cancer, cognition, and suicidal ideation