Health and Psychosocial Outcomes of a Telephonic Couples Behavior Change Intervention in Patients With Poorly Controlled Type 2 Diabetes: A Randomized Clinical Trial

OBJECTIVE To compare glycemic control and secondary outcomes of a 4-month telephonic couples behavioral intervention to individual intervention, and to education, for adults with type 2 diabetes. RESEARCH DESIGN AND METHODS A randomized trial with the following three arms: couples calls (CC) (n = 104); individual calls (IC) (n = 94); and diabetes education (DE) (n = 82). All arms had self-management education (two calls). CC and IC had 10 additional behavior change calls. CC addressed collaboration and relationships/communication. Participants consisted of 280 couples, among whom one partner had type 2 diabetes and an A1C level ≥7.5%. Blinded assessments occurred at 4, 8, and 12 months. The primary outcome was change in A1C; and secondary outcomes were BMI, waist circumference, blood pressure, depressive symptoms, diabetes self-efficacy, and diabetes distress. RESULTS Patients had a mean age of 56.8 years; 61.6% were male, and 30.4% were minorities. The baseline mean A1C level was 9.1%. Intention-to-treat analyses found significant A1C reductions for all (12 months: CC -0.47%, IC -0.52%, DE -0.57%), with no differences between arms. Preplanned within-arm analyses were stratified by baseline A1C tertiles: lowest tertile (7.5-8.2%), no change from baseline; middle tertile (8.3-9.2%), only CC led to significantly lower A1C level; and highest tertile (≥9.3%), significant improvement for all interventions. For BMI, CC showed significant improvement, and CC and DE led to decreased waist circumference. The IC group showed greater blood pressure improvement. Results for secondary psychosocial outcomes favored the CC group. CONCLUSIONS In adults with poorly controlled type 2 diabetes, a collaborative couples intervention resulted in significant, lasting improvement in A1C levels, obesity measures, and some psychosocial outcomes. For those with exceedingly high A1C levels, education alone was beneficial, but additional intervention is needed to achieve glycemic targets.