Date Published: March 20, 2018
Publisher: Public Library of Science
Author(s): Kunal N. Karmali, Donald M. Lloyd-Jones, Joep van der Leeuw, David C. Goff, Salim Yusuf, Alberto Zanchetti, Paul Glasziou, Rodney Jackson, Mark Woodward, Anthony Rodgers, Bruce C. Neal, Eivind Berge, Koon Teo, Barry R. Davis, John Chalmers, Carl Pepine, Kazem Rahimi, Johan Sundström, Steven R. Steinhubl
Abstract: BackgroundClinical practice guidelines have traditionally recommended blood pressure treatment based primarily on blood pressure thresholds. In contrast, using predicted cardiovascular risk has been advocated as a more effective strategy to guide treatment decisions for cardiovascular disease (CVD) prevention. We aimed to compare outcomes from a blood pressure-lowering treatment strategy based on predicted cardiovascular risk with one based on systolic blood pressure (SBP) level.Methods and findingsWe used individual participant data from the Blood Pressure Lowering Treatment Trialists’ Collaboration (BPLTTC) from 1995 to 2013. Trials randomly assigned participants to either blood pressure-lowering drugs versus placebo or more intensive versus less intensive blood pressure-lowering regimens. We estimated 5-y risk of CVD events using a multivariable Weibull model previously developed in this dataset. We compared the two strategies at specific SBP thresholds and across the spectrum of risk and blood pressure levels studied in BPLTTC trials. The primary outcome was number of CVD events avoided per persons treated. We included data from 11 trials (47,872 participants). During a median of 4.0 y of follow-up, 3,566 participants (7.5%) experienced a major cardiovascular event. Areas under the curve comparing the two treatment strategies throughout the range of possible thresholds for CVD risk and SBP demonstrated that, on average, a greater number of CVD events would be avoided for a given number of persons treated with the CVD risk strategy compared with the SBP strategy (area under the curve 0.71 [95% confidence interval (CI) 0.70–0.72] for the CVD risk strategy versus 0.54 [95% CI 0.53–0.55] for the SBP strategy). Compared with treating everyone with SBP ≥ 150 mmHg, a CVD risk strategy would require treatment of 29% (95% CI 26%–31%) fewer persons to prevent the same number of events or would prevent 16% (95% CI 14%–18%) more events for the same number of persons treated. Compared with treating everyone with SBP ≥ 140 mmHg, a CVD risk strategy would require treatment of 3.8% (95% CI 12.5% fewer to 7.2% more) fewer persons to prevent the same number of events or would prevent 3.1% (95% CI 1.5%–5.0%) more events for the same number of persons treated, although the former estimate was not statistically significant. In subgroup analyses, the CVD risk strategy did not appear to be more beneficial than the SBP strategy in patients with diabetes mellitus or established CVD.ConclusionsA blood pressure-lowering treatment strategy based on predicted cardiovascular risk is more effective than one based on blood pressure levels alone across a range of thresholds. These results support using cardiovascular risk assessment to guide blood pressure treatment decision-making in moderate- to high-risk individuals, particularly for primary prevention.
Partial Text: Clinical practice guidelines for hypertension treatment have traditionally relied primarily on blood pressure levels to guide use of blood pressure-lowering medications [1–4]. However, single risk factor levels, like blood pressure, incompletely capture risk. Furthermore, blood pressure-lowering medications provide a fairly consistent relative risk reduction across a range of blood pressure levels, leading to large variations in absolute benefit from blood pressure treatment observed among individuals [5–7].
This analysis followed a prespecified protocol that was presented to the BPLTTC Steering committee in April 2013.
This analysis of nearly 50,000 persons studied in clinical trials demonstrated that a blood pressure-lowering treatment strategy based on predicted CVD risk could prevent more events for the same number of persons treated compared with a strategy based on SBP levels. The benefit of the CVD risk strategy was particularly evident at higher SBP thresholds and for persons without prevalent CVD or diabetes mellitus.