The Pathways Study: a randomized trial of collaborative care in patients with diabetes and depression

There is a high prevalence of depression in patients with diabetes mellitus. Depression has been shown to be associated with poor self-management (adherence to diet, exercise, checking blood glucose levels) and high hemoglobin A1c (HbA1c) levels in patients with diabetes.

To determine whether enhancing quality of care for depression improves both depression and diabetes outcomes in patients with depression and diabetes.

Randomized controlled trial with recruitment from March 1, 2001, to May 31, 2002.

Nine primary care clinics from a large health maintenance organization.

A total of 329 patients with diabetes mellitus and comorbid major depression and/or dysthymia. Intervention Patients were randomly assigned to the Pathways case management intervention (n = 164) or usual care (n = 165). The intervention provided enhanced education and support of antidepressant medication treatment prescribed by the primary care physician or problem-solving therapy delivered in primary care.

Independent blinded assessments at baseline and 3, 6, and 12 months of depression (Hopkins Symptom Checklist 90), global improvement, and satisfaction with care. Automated clinical data were used to evaluate adherence to antidepressant regimens, percentage receiving specialty mental health visits, and HbA1c levels.

When compared with usual care patients, intervention patients showed greater improvement in adequacy of dosage of antidepressant medication treatment in the first 6-month period (odds ratio [OR], 4.15; 95% confidence interval [CI], 2.28-7.55) and the second 6-month period (OR, 2.90; 95% CI, 1.69-4.98), less depression severity over time (z = 2.84, P = .004), a higher rating of patient-rated global improvement at 6 months (intervention 69.4% vs usual care 39.3%; OR, 3.50; 95% CI, 2.16-5.68) and 12 months (intervention 71.9% vs usual care 42.3%; OR, 3.50; 95% CI, 2.14-5.72), and higher satisfaction with care at 6 months (OR, 2.01; 95% CI, 1.18-3.43) and 12 months (OR, 2.88; 95% CI, 1.67-4.97). Although depressive outcomes were improved, no differences in HbA1c outcomes were observed.

The Pathways collaborative care model improved depression care and outcomes in patients with comorbid major depression and/or dysthymia and diabetes mellitus, but improved depression care alone did not result in improved glycemic control.