Previous research has suggested that emerging evidence from randomized controlled trials (RCTs) is often not reflected in physician selection of medication class for first-line anti-hypertensive therapy.
To evaluate the association of RCT evidence in December 2002 from the Antihypertensive and Lipid-Lowering treatment to prevent Heart Attack Trial (ALLHAT) on use of anti-hypertensive medications over time in a multi-ethnic cohort.
The Multi-Ethnic Study of Atherosclerosis study, a prospective cohort study of 6,814 adults from 4 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 antihypertensive medications.
After the exclusion of antihypertensive 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).
The randomized trial evidence from the ALLHAT study was temporally associated with a moderate increase in diuretic use.