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The most effective blood-pressure goals for treatment with antihypertensive medications are uncertain. Treating hypertension to standard systolic blood-pressure goals is cost-saving or cost-effective among patients at high risk for cardiovascular disease in the United States.1 However, until recently, evidence from randomized trials did not clearly support intensive control of systolic blood pressure.2–4
The Systolic Blood Pressure Intervention Trial (SPRINT) showed significant reductions in the rates of death and cardiovascular disease events with intensive systolic blood-pressure control (intensive control; target, <120 mm Hg) versus standard control (target, <140 mm Hg) among adults at high risk for cardiovascular disease who had no history of diabetes, stroke, or heart failure.5,6 Intensive control may prevent cardiovascular disease events in high-risk patients and reduce health care costs, as compared with standard control, but these benefits must be weighed against the increased risk of serious adverse events and higher implementation costs (e.g., additional office visits, laboratory tests, and medications). The purpose of this SPRINT cost-effectiveness study was to estimate lifetime health gains and averted health care costs with intensive control after considering increased treatment costs and the risks of treatment-related serious adverse events.
Methods
Microsimulation Model
We developed a microsimulation model to estimate costs, clinical outcomes, and quality-adjusted life-years (QALYs) of systolic blood-pressure control in SPRINT-eligible adults (Figure 1; and Figs. S1 and S2 in the Supplementary Appendix, available with the full text of this article at NEJM.org). The model compared the lifetime incremental cost-effectiveness of intensive control with that of standard control with the use of 6-month cycles. We accounted for health gained and lost to society due to intensive control and for payers’ direct health care costs; patients’ indirect costs were not included.
We used SPRINT results to estimate the risk of death from all causes and from cardiovascular causes, cardiovascular disease events, and serious adverse events in 10,000 hypothetical patients who shared the same baseline characteristics, inclusion criteria, and number of intervention medications with SPRINT participants (Table 1, and Table S1 in the Supplementary Appendix).6 Cardiovascular disease events included acute myocardial infarction, acute coronary syndrome not resulting in myocardial infarction, stroke, and heart failure. Serious adverse events of interest were hypotension, syncope, bradycardia, electrolyte abnormalities, and acute kidney injury.6