The impact of blood glucose monitoring on depression and distress in insulin-naive patients with type 2 diabetes

Objective: To test whether a structured self-monitoring of blood glucose (SMBG) protocol reduces depressive symptoms and diabetes distress. Research design and methods: A 12-month, cluster-randomised, clinical trial compared patients who received a collaborative, structured SMBG, physician/patient intervention with an active control. Studied were 483 insulin naive type 2 diabetes patients (experimental = 256, control = 227) (>= 7.5% HbA1c) from 34 primary care practices (experimental = 21, control = 13). Experimental patients used a paper tool to record a 7-point SMBG profile on each of three consecutive days prior to their quarterly physician visit. Patients and physicians interpreted SMBG results to make medication and lifestyle changes. Clinical trial registration: NIH Trial Registry Number: NCT00674986. Main outcome measures: Depressive symptoms (Patient Health Questionnaire: PHQ-8), diabetes-related distress (Diabetes Distress Scale: DDS). HbA1c and SMBG frequency were assessed quarterly; data were analysed using Linear Mixed Models (LMM) for intent-to-treat (ITT) and per protocol (PP) analyses. Results: ITT analyses showed significant improvement in depression and disease-related distress among experimental and control patients from baseline to 12 months (p < 0.01 in both cases) with no between-group differences. Experimental patients displayed significantly greater reductions in distress related to regimen adherence than controls. Also, experimental patients with elevated diabetes distress or depressive symptoms at baseline showed significantly greater reductions in distress and depressive symptoms than control patients at 12 months. The greater improvement in mood in the experimental than control group was independent of improvements in glycaemic control and changes in SMBG frequency. Conclusions: Using well standardised measures, collaborative, structured SMBG leads to reductions, not increases, in depressive symptoms and diabetes distress over time, for the large number of moderately depressed or distressed type 2 patients in poor glycaemic control. Changes in affective status are independent of improvements in glycaemic control and changes in SMBG frequency for these patients.