Atenolol as initial antihypertensive therapy: an observational study comparing first-line agents

Objective The role of atenolol in the management of patients with hypertension is currently under scrutiny. Our aim was to evaluate the real-world consequences of recent clinical trial findings. Methods We conducted a retrospective, cohort study using linked administrative data from the province of Saskatchewan, Canada. Eligible subjects were first-ever users of antihypertensive medications between 1 January 1994 and 31 December 2003 and were grouped into four cohorts: atenolol, angiotensin-converting enzyme inhibitors (ACEI), thiazide diuretics, or calcium antagonists. Patients remained eligible during monotherapy only. Results We identified 19 249 eligible individuals ( mean age 60.6 years) who were followed for a mean of 2.3 years (SD 2.0). The rate of myocardial infarction, unstable angina, stroke, or death occurred in similar frequencies among all cohorts: atenolol (2.3%), ACEI (3.6%), thiazide diuretics (2.9%), and calcium antagonists (3.9%). After adjustment for potential confounders, atenolol therapy was not associated with higher event rates than the other first-line agents, with hazard ratios ranging between 1.03 [95% confidence intervals (CI) 0.72-1.46] and 1.24 (95% CI 0.91-1.68) for all cohorts compared with atenolol. Similar results were observed upon stratifying the sample into subjects above and below 60 years of age. Conclusion The low event rates for all cohorts suggest that atenolol has not been associated with a significant burden of cardiovascular morbidity or mortality in its traditional role for uncomplicated hypertension. Further study is needed to identify the specific types of patients that should avoid atenolol as an antihypertensive agent.