Implementation of the Chronic Care Model to Reduce Disparities in Hypertension Control: Benefits Take Time

Background: The Chronic Care Model (CCM) has been endorsed by experts to reduce disparities in chronic disease outcomes but benefits may be slow to appear in low-income populations.

Objective: To evaluate the effect of CCM implementation on systolic blood pressure (SBP) control in minority patients with diabetes mellitus (DM).

Design: Retrospective study from 2012 to 2016 in two primary care clinics with primarily uninsured, Hispanic patients.

Patients: Four 2-year cohorts of patients aged 18-75 with DM and SBP ≥ 140 mmHg on HTN drugs in year 1 and SBP measured 1 year later in year 2.

Intervention: Implementation of CCM for DM in January 2014 involved: electronic medical record revision, a DM registry, hypertension (HTN) treatment protocol, team education, performance feedback, and case management.

Main Measure: SBP < 140 mmHg in year 2.

Key Results: Of 2354 patients, the mean age was 56.2 (SD 9.5), baseline SBP 153.8 (SD 14.9) mmHg, and 79.8% Hispanic. Last SBP < 140 mmHg was 58.4% for cohort 1 (2012-2013) and 68.5% for cohort 4 (2015-2016). Adjusted odds ratios (AORs) for SBP control versus cohort 1 were 1.35 (95% CI 1.07, 1.69) for cohort 3 (2014-2015) and 2.13 (95% CI 1.60, 2.80) for cohort 4. AORs for SBP control were reduced by 15% per HTN drug at baseline (P = 0.001), 9% per HTN drug added at last SBP (P = 0.024), and 22% for multi-dose HTN drugs (P = 0.004). Among patients with persistent elevated SBP and represented in multiple cohorts, AORs for control were still over 2-fold higher for cohort 4 versus cohort 1.

Conclusions: After adopting the CCM for primarily Hispanic patients with DM, SBP control increased significantly despite treatment with fewer HTN drugs. Yet improvement took 3-4 years, suggesting that financial rewards for using the CCM to achieve improved clinical outcomes for low-income, minority patients may be delayed.