1. Among older adult patients with subclinical depression, a collaborative care intervention reduced depressive symptoms at 4 and 12 months compared to usual primary care.
2. Patients receiving collaborative care were less likely to meet criteria for clinical depression at 12 months of follow-up.
Evidence Rating Level: 2 (Good)
Study Rundown: Depression is the second leading cause of disability worldwide. Subclinical depression is a significant risk factor for the development of severe depressive disorder, and with an established prevalence of 1 in 7, is common among elderly patients. However, there is little current data to guide the diagnosis and treatment of older patients with subclinical depression.
This randomized controlled trial, conducted at 32 clinics across the UK, evaluated the effect of collaborative care—defined as the provision of care by a trained case manager using the principles of chronic disease management—as an intervention for older people with subthreshold depression. The study found that compared to usual care, patients who received collaborative care had significantly fewer self-reported symptoms of depression at 4 months and 12 months of follow-up (PHQ-9 Score). While there was no difference in the proportion of patients who went on to develop clinical depression after 4 months of care, those who received collaborative care were less likely to meet criteria for depression after 12 months.
This study suggests that older patients with subclinical depression may benefit from the receipt of collaborative care. However, the study was limited in a few ways. First, while investigators were blinded, both patients and clinicians were aware of their allocated treatment—a potential source of bias. Second, confirmation of depression was not done using the traditional diagnostic interview. Finally, more patients in the collaborative care arm were lost to follow-up, potentially skewing the observed outcomes.
In-Depth [randomized controlled study]: This study evaluated the effectiveness of collaborative care versus usual care on reducing depressive symptoms in older people with subthreshold depression. This study was a multicenter, randomized control study, encompassing 32 primary care clinics in Northern England. Patients were 65 years of age or older and were screened for depressive symptoms based on the Wholley questionnaire, of which subclinical depression was confirmed according to the DSM-IV (MINI version 5.0). The primary outcome was self-reported severity and symptoms of depression assessed by the 9-item Patient Health Questionnaire (PHQ-9) at 4 months. Secondary exploratory outcomes included PHQ-9 depression severity at 12 months and dichotomized depression according to “depression diagnosis,” defined using an optimum cut point of a PHQ-9 score ≥10 (at 4 and 12 months).
In the study, 705 patients were randomized to receive either collaborative care (N=344) or usual care (N=361). Ultimately, due to various factors such as death, withdrawal from follow-up, or missing outcome data, only 274 patients from the collaborative care group and 327 patients from the usual care group were included in primary analyses. At 4-month follow-up there was a between group difference of −1.31 PHQ-9 score points (95%CI, −1.95 to −0.67; P < 0.001) in favor of collaborative care. At 12-month follow-up, the between-group difference remained significant (−1.33, PHQ-9 score points; 95%CI, −2.10 to −0.55; P = 0.001).
As a secondary measure, the proportion of participants with a new depression diagnosis (PHQ-9 score ≥10) was lower in the collaborative care group at 12-month follow-up (12 months: 15.7% vs 27.8%; difference, −12.1%; 95% CI, −19.1% to −5.1%; RR, 0.65 [95% CI, 0.46- 0.91]; P = .01), but not significant at 4-month follow-up.
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