Trust and Glycemic Control in Black Patients With Diabetic Retinopathy: A Pilot Study

Diabetic retinopathy (DR) is more prevalent in blacks than whites because, compared to whites, blacks on average have worse glycemic control. Both of these racial disparities reflect differences in sociocultural determinants of health, including physician mistrust. This randomized, controlled 6-month pilot trial compared the efficacy of a culturally tailored behavioral health/ophthalmologic intervention called Collaborative Care for Depression and Diabetic Retinopathy (CC-DDR) to enhanced usual care (EUC) for improving glycemic control in black patients with DR (n = 33). The mean age of participants was 68 years (SD 6.1 years), 76% were women, and the mean A1C was 8.7% (SD 1.5%). At baseline, 14 participants (42%) expressed mistrust about ophthalmologic diagnoses. After 6 months, CC-DDR participants had a clinically meaningful decline in A1C of 0.6% (SD 2.1%), whereas EUC participants had an increase of 0.2% (SD 1.1%) (f[1, 28] = 1.9; P = 0.176). Within CC-DDR, participants with trust had a reduction in A1C (1.4% [SD 2.5%]), whereas participants with mistrust had an increase in A1C (0.44% [SD 0.7%]) (f[1, 11] = 2.11; P = 0.177). EUC participants with trust had a reduction in A1C (0.1% [SD 1.1%]), whereas those with mistrust had an increase in A1C (0.70% [SD 1.1%]) (f[1, 16] = 2.01; P = 0.172). Mistrust adversely affected glycemic control independent of treatment. This finding, coupled with the high rate of mistrust, highlights the need to target mistrust in new interventions to improve glycemic control in black patients with DR.