Medical clinics versus usual care for patients with both diabetes and hypertension: a randomized trial

Abstract

Background: Group medical clinics (GMCs) are widely used in the management of diabetes and hypertension, but data on their effectiveness are limited.

Objective: To test the effectiveness of GMCs in the management of comorbid diabetes and hypertension.

Design: Randomized, controlled trial. (ClinicalTrials.gov registration number: NCT00286741)

Setting: 2 Veterans Affairs Medical Centers in North Carolina and Virginia.

Patients: 239 patients with poorly controlled diabetes (hemoglobin A(1c) [HbA(1c)] level > or =7.5%) and hypertension (systolic blood pressure >140 mm Hg or diastolic blood pressure >90 mm Hg).

Intervention: Patients were randomly assigned within each center to either attend a GMC or receive usual care. Clinics comprised 7 to 8 patients and a care team that consisted of a primary care general internist, a pharmacist, and a nurse or other certified diabetes educator. Each session included structured group interactions moderated by the educator. The pharmacist and physician adjusted medication to manage each patient's HbA(1c) level and blood pressure.

Measurements: Hemoglobin A(1c) level and systolic blood pressure, measured by blinded research personnel at baseline, study midpoint (median, 6.8 months), and study completion (median follow-up, 12.8 months). Linear mixed models, adjusted for clustering within GMCs, were used to compare HbA(1c) levels and systolic blood pressure between the intervention and control groups.

Results: Mean baseline systolic blood pressure and HbA(1c) level were 152.9 mm Hg (SD, 14.2) and 9.2% (SD, 1.4), respectively. At the end of the study, mean systolic blood pressure improved by 13.7 mm Hg in the GMC group and 6.4 mm Hg in the usual care group (P = 0.011 by linear mixed model), whereas mean HbA(1c) level improved by 0.8% in the GMC group and 0.5% in the usual care group (P = 0.159).

Limitation: Measurements of effectiveness may have been limited by concomitant improvements in the usual care group that were due to co-intervention.

Conclusion: Group medical clinics are a potent strategy for improving blood pressure but not HbA(1c) level in diabetic patients.

Primary funding source: U.S. Department of Veterans Affairs Health Services Research and Development Service.