Objective: Hypertension affects more than 50 million people in the United States alone. Despite clear evidence regarding the beneficial effects of quality treatment for high blood pressure, many millions of diagnosed and undiagnosed hypertensives are not receiving the optimal standard of care. The difference in patient outcomes achieved with present hypertension treatment methods and those thought to be possible using best practice treatment methods is known as a quality gap, and such gaps are at least partly responsible for the loss of thousands of lives each year. This review was organized to bring a systematic assessment of different quality improvement (QI) strategies and their effects to the process of identifying and managing hypertension.

Search Strategy and Inclusion Criteria: Investigators searched the MEDLINE^® database, the Cochrane Collaboration's Effective Practice and Organisation of Care (EPOC) registry, article bibliographies, and relevant journals for experimental evaluations of QI interventions aimed at improving hypertension screening and management of non-pregnant adults with primary hypertension. The reviewers included randomized or quasi-randomized controlled trials, controlled before-after studies, and interrupted time series in which at least one reported outcome measure included changes in blood pressure, or provider or patient adherence to a recommended process of care.

Data Collection and Analysis: Relevant data were abstracted independently by two reviewers. Each QI intervention was classified into one or more of the following components: provider education, provider reminders, facilitated relay of clinical information, patient education, promotion of self-management, patient reminders, audit and feedback, organizational change, or financial incentives. Certain categories were further subdivided into major subtypes (e.g., professional meetings for provider education and disease management for organizational change). The researchers also evaluated the impact of clinical information systems as a mediator for interventions of all types. They compared the different QI strategies in terms of the median effects achieved for blood pressure control and for a generalized measure of provider or patient adherence.

Main Results: Sixty-three articles reporting a total of 82 comparisons met the inclusion criteria. Studies of hypertension identification were found to be too heterogeneous for quantitative analysis. The majority of screening studies were clinic-based (with a few offered at work sites), and the most common strategies involved patient and/or provider reminders. These generally showed positive results; several studies found that patients were more likely to know their blood pressure or attend clinic visits after receiving reminders. Across all studies with a variety of strategies, the median reductions in systolic blood pressure (SBP) and diastolic blood pressure (DBP) were 4.5 mmHg (interquartile range: 1.5, 11.0) and 2.1 mmHg (interquartile range: -0.2, 5.0), respectively. The median increase in the proportion of patients in the target SBP range and target DBP range was 16.2 percent (interquartile range: 10.3, 32.2), and 6.0 percent (interquartile range: 1.5, 17.5), respectively. Studies that focused on improving provider adherence showed a range of median reduction of 1.3 percent to a median improvement of 3.3 percent across all QI strategies. Overall, patient adherence showed a median improvement of 2.8 percent (interquartile range: 1.9, 3.0).

Conclusion: The findings of this review suggest that QI strategies appear, in general, to be associated with the improved identification and control of hypertension. It is not possible to discern with complete confidence which specific QI strategies have the greatest effects, since most of the studies included more than one QI strategy. All of the assessed strategies may be beneficial under some circumstances, and in varying combinations. There may be other useful strategies that have not been studied in trials meeting the inclusion criteria for evidence-based review; it is not possible to draw conclusions about these strategies.