Hypertension Improvement Project (HIP): study protocol and implementation challenges

Background: Hypertension affects 29% of the adult U. S. population and is a leading cause of heart disease, stroke, and kidney failure. Despite numerous effective treatments, only 53% of people with hypertension are at goal blood pressure. The chronic care model suggests that blood pressure control can be achieved by improving how patients and physicians address patient self-care. Methods and design: This paper describes the protocol of a nested 2 x 2 randomized controlled trial to test the separate and combined effects on systolic blood pressure of a behavioral intervention for patients and a quality improvement-type intervention for physicians. Primary care practices were randomly assigned to the physician intervention or to the physician control condition. Physician randomization occurred at the clinic level. The physician intervention included training and performance monitoring. The training comprised 2 internet-based modules detailing both the JNC-7 hypertension guidelines and lifestyle modifications for hypertension. Performance data were collected for 18 months, and feedback was provided to physicians every 3 months. Patient participants in both intervention and control clinics were individually randomized to the patient intervention or to usual care. The patient intervention consisted of a 6-month behavioral intervention conducted by trained interventionists in 20 group sessions, followed by 12 monthly phone contacts by community health advisors. Follow-up measurements were performed at 6 and 18 months. The primary outcome was the mean change in systolic blood pressure at 6 months. Secondary outcomes were diastolic blood pressure and the proportion of patients with adequate blood pressure control at 6 and 18 months. Discussion: Overall, 8 practices (4 per treatment group), 32 physicians (4 per practice; 16 per treatment group), and 574 patients (289 control and 285 intervention) were enrolled. Baseline characteristics of patients and providers and the challenges faced during study implementation are presented. The HIP interventions may improve blood pressure control and lower cardiovascular disease risk in a primary care practice setting by addressing key components of the chronic care model. The study design allows an assessment of the effectiveness and cost of physician and patient interventions separately, so that health care organizations can make informed decisions about implementation of 1 or both interventions in the context of local resources. Trial registration: ClinicalTrials.gov identifier NCT00201136