Background: Previous reports have suggested that new evidence of the comparative effectiveness of different medication classes from randomized controlled trials (RCTs) does not always alter treatment decisions for first-line anti-hypertensive therapy.
Objectives: To evaluate the association of RCT evidence in December 2002 from the Anti-hypertensive and Lipid-Lowering treatment to prevent Heart Attack Trial (ALLHAT) on use of anti-hypertensive medications in a multi-ethnic cohort.
Methods: The Multi-Ethnic Study of Atherosclerosis (MESA) study, a prospective cohort study of 6814 adults from four ethnic groups, had four separate assessments of drug use. Users of anti-hypertensive medications at baseline were excluded. We evaluated temporal changes in the medication class reported by new users of anti-hypertensive medications.
Results: After the exclusion of anti-hypertensive drug users at baseline, 32% of new users of anti-hypertensive drugs seen at exam 2 were prescribed a diuretic. The publication of ALLHAT was associated with a subsequent increase in the proportion of new users taking diuretics at exam 3 compared with exam 2 (relative risk (RR): 1.31; 95% confidence interval (CI): 1.09-1.59). After the report from ALLHAT, the proportion of users of diuretics seen at exam 3 rose to 44% (starting in 2004) and 39% in exam 4 (starting in 2005). This increase in the proportion of diuretic use among new users of anti-hypertensive medications declined slightly but could still be detected at exam 4 as compared to exam 2 (RR: 1.28; 95%CI: 1.04-1.57).
Conclusions: The randomized trial evidence from the ALLHAT study was temporally associated with a moderate increase in diuretic use.