Abstract P148: Effect of Apparent Treatment Resistant Hypertension on Cardiovascular Disease Events and Modification by Sex
Apparent treatment resistant hypertension (ATRH) is an important health concern in the U.S. affecting approximately 9% of all hypertensive adults and growing. However, long-term prognosis of those with ATRH remains to be fully investigated, especially with regard to the presence of differences by sex. Using data from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) we examined the relationship between ATRH and CVD and effect modification by sex. Subjects in ALLHAT were 55 years or older (N male = 13,597 and N female = 11,919) and were randomized to one of four antihypertensive medications for the purposes of the trial. We used Cox Proportional Hazard models and tested for interaction of sex through use of a multiplicative interaction term, stratified analyses, the Aalen Additive Hazards model, and joint effects. Missing blood pressure readings were imputed using multiple imputation as a sensitivity analysis. Due to the design of ALLHAT, ATRH was assessed at the year 2 follow-up visit and subjects were then followed for an additional 6 years (average follow-up 4.7 years) during this time there were 5,030 CVD events. Overall (N=25,516), ATRH was associated with an approximate 30% increased risk of CVD (HR 1.30, 95% CI 1.19 – 1.42) compared to those without ATRH. This risk was greater in women than in men (p interaction <.0001). In women, ATRH was associated with an approximate 62% increase in risk of CVD (HR 1.62, 95% CI 1.41 – 1.86) while in men, ATRH was associated with an approximate 13% increase in risk of CVD (HR 1.13, 95% CI 1.01 – 1.27). Sex was also a modifier of the relationship on the additive scale (p-value 0.003). ATRH is associated with an increased risk of developing CVD and women with ATRH were at a greater risk of developing CVD compared to men. These findings provide important insights into the complex relationship between ATRH and cardiovascular health, and suggest that women, in particular, may be a high-risk subgroup. Thus future studies should examine these differences to aid in development of targeted treatment and interventions which would have a significant public health benefit.