Cost implications of improving blood pressure management among U.S. adults.

Despite being one of the most important and common chronic diseases, hypertension is substantially underdiagnosed and undertreated. Reducing blood pressure by 10/5 mmHg lowers the risk of coronary heart disease events by 22 percent and strokes by 41 percent over about 5 years (Law, Morris, and Wald 2009). Of U.S. adults, 23 percent report having hypertension while another 7 percent have elevated blood pressures without a diagnosis. Only 68 percent of people with hypertension are taking medications (Ong et al. 2007; Ostchega et al. 2008;). Suboptimal management by health care providers contributes to poor control (Wang and Vasan 2005). According to the most comprehensive assessment of quality of care to date, the Community Quality Index (CQI) study, U.S. adults receive 65 percent of recommended care processes for hypertension (McGlynn et al. 2003). Basic elements of blood pressure management are substantially underused, including making a diagnosis, initiating and adjusting medications, and monitoring blood pressure (Berlowitz et al. 1998; Andrade et al. 2004; Spranger et al. 2004; Wang and Vasan 2005; Milchak et al. 2008;). The National Committee on Quality Assurance's Health Care Effectiveness Data and Information Set (HEDIS) enables health plans to monitor and report the quality of the care their enrollees receive. Ninety percent of health plans participate in the HEDIS program and employers consider HEDIS scores in health care purchasing decisions (National Committee for Quality Assurance 2009), giving health plans incentives to improve quality of care. The HEDIS measure for hypertension assesses a short-term outcome, the attainment of treatment goals (blood pressure <140/90 overall and <130/80 with diabetes mellitus). Eddy et al. (2008) recently determined that increasing the attainment of HEDIS goals from 28 percent to 100 percent of U.S. adults with hypertension would prevent 719,000 myocardial infarctions, 379,000 deaths from coronary heart disease, and 1,200,000 strokes over 10 years. Although improved control would offer substantial health benefits, health care payers may be concerned about the potential cost. The cost-effectiveness of treating hypertension is well established from the societal perspective, but most studies are 10–20 years old, address nonrepresentative populations, and compare treatment with no treatment (Brown and Garber 2000; Krumholz et al. 2002; Mullins, Blak, and Akhras 2002;). Data are limited on the cost of improving quality relative to current levels (Lapuerta et al. 2001; Paramore et al. 2001; Kahn et al. 2008;). Further, although payers play major roles in quality assessment and can align financial incentives with improvement, costs and benefits of interest to payers have received limited attention. Private payers are likely to consider short-term costs and cost-effectiveness, such as the cost of improving adherence to HEDIS measures, because enrollee turnover is substantial (Cunningham 2000). Longer-term costs may be more important to payers with lower turnover, such as public payers, but much of the U.S. population has private insurance. Our objective was to estimate the cost and cost-effectiveness to payers of consistently providing the basic elements of blood pressure management to U.S. adults with hypertension. We focused on process-of-care criteria because they can account for variations in patients' needs, identify which processes warrant improvement, and isolate aspects of care under providers' rather than patients' control. Also, the cost associated with providing recommended care processes is readily quantifiable (Brook, McGlynn, and Cleary 1996). Taking the payer perspective influenced the study time horizon (2 years) and measure of clinical effectiveness (attainment of treatment goals). While accounting practices involve a 1-year horizon, a 2-year horizon is preferable for examining hypertension care processes in detail because blood pressure varies across visits and 6 months can pass between recommended visits. Although conducting cost-effectiveness studies alongside randomized controlled trials produces precise estimates for the enrolled populations, we used a modeling approach because it can generate estimates representative of the U.S. population. To date, the CQI study represents the only nationally representative data on the quality of care processes for hypertension. Using data from this study, we identified care processes that are recommended for individual patients, assessed how frequently those processes were provided, and determined how often patients attained treatment goals over 2 years. We then modeled how direct costs to payers and goal attainment would change if all recommended care processes were provided. We considered coronary heart disease events and strokes in supplemental analyses because they involve longer time horizons.