Abstract 11020: Legacy Effects of Baseline Blood Pressure ‘Treatment Naivety’ on All-cause and Cardiovascular Mortality in the Antihypertensive and Lipid-lowering Treatment to Prevent Heart Attack Trial (ALLHAT)

• Published in: Circulation (New York, N.Y.) N.Y.), 2019-11, Vol.140 (Suppl_1 Suppl 1), p.A11020-A11020
• Main Authors: Ho, Chau, Bresliln, Monique, Chowdhury, Enayet, Doust, Jenny, Reid, Christopher M, Davis, Barry R, Simpson, Lara M, Nelson, Mark R
• Format: Article
• Language: English
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/circ.140.suppl_1.11020

IntroductionContemporary guidelines for the primary prevention of cardiovascular disease (CVD) are predominantly based on absolute CVD risk stratification for drug treatment decision making. Individuals with a blood pressure (BP) above the threshold of 140/90 mmHg are not treated unless absolute risk is assessed as high. A barrier to this approach is physicians concern that delaying in drug treatment may result in irreversible end-organ damage or ‘legacy effects’.ObjectivesTo investigate legacy effects after 14-years follow-up by comparing individuals who had been previously treated and treatment-naïve individuals at entry into the ALLHAT study on all-cause and CVD mortality.MethodsA post-hoc observational study of the ALLHAT Trial. We excluded participants with a previous history of CVD events. Based on BP lowering treatment status at baseline, participants were stratified to ‘treatment naïve’(TN) and previous treatment (PT) groups. A Cox proportional hazard model was used to estimate the effects of prior antihypertensive treatment on mortality outcomes. Also, a subgroup analysis stratified by estimated 10-year Framingham risk score (FRS) was performed.ResultsThe current study included 15,658 participants. In unadjusted models, the TN group had a significantly lower risk of 14-year all-cause and CVD mortality with HR 0.92 (0.85-0.99) and 0.84 (0.73-0.97) respectively. In multivariable models adjusting for baseline and in-trial characteristics (BP values and number of BP medications as time-dependent variables), the difference became non-significant with HR 0.95 (0.88-1.03) for 14-year all-cause mortality and HR 0.93 (0.80-1.08) for 14-year CVD mortality. In a subgroup analysis stratified by absolute CVD risk, there was no heterogeneity of the association between TN and short- or long-term all-cause or CVD mortality recorded.ConclusionsWhilst we recommend caution with interpretation as results may be biased due to unobserved residual confounding, this study found no evidence of an adverse effect from delaying blood pressure treatment when adjusted for baseline blood pressure and treatment intensity. The non-significant association was consistent across the CVD risk subgroups.