Only about half of adults with hypertension have controlled blood pressure, and clinic performance varies widely despite quality improvement efforts. A mixed-methods comparative case study published in the Journal of the American Heart Association evaluated factors associated with this variation across a statewide cardiovascular health collaborative.

Forty-eight primary care clinics caring for 357,158 patients implemented quality improvement (QI) programs focused on blood pressure control. Eight clinics were selected for detailed comparison based on pre- and post-implementation performance, practice type, and location. High-performing clinics reported blood pressure improvement of 11.7% to 15.2% among 1,364 patients, while low-performing clinics showed declines of 1.8% to 11.2% among 3,614 patients.

Site observations and team interviews showed common supports across clinics, including QI coaching, routine data review, regular meetings, use of program tools, and commitment to improvement efforts. Common obstacles included workforce shortages, internal operational challenges, and competing priorities.

Despite similar facilitators and barriers, higher-performing clinics more often addressed challenges proactively, whereas lower-performing clinics responded more reactively. The findings suggest implementation style may help explain variation in blood pressure control gains across clinics.