To assess the equivalence of four antihypertensive treatments in patients with mild-to-moderate hypertension, and to compare the effects of those drugs on the subjective quality of life and clinical safety.
Design, setting and patients:
653 patients aged ≥18 years with untreated hypertension were randomly allocated to receive a combination of two diuretics (altizide and spironolactone), a β -blocker (bisoprolol), a calcium antagonist (verapamil), or an angiotensin converting enzyme (ACE) inhibitor (enalapril). Follow-up lasted for 1 year.
Main outcome measures:
A composite outcome of the following measures was used to define success: attendance at the 12-month visit; at least nine supine DBP measurements during the study; and median supine DBP<90mmHg and a reduction of at least l0mmHg compared with the baseline value. Failure was defined as one or more of those criteria not being fulfilled. Equivalence was concluded if the 95% confidence interval for the success rates differed between two groups by less than ±10%. Clinical safety and subjective quality of life were also assessed.
No statistically significant differences in the change in DBP or systolic blood pressure were observed between the groups. The success rates were 43.9, 42.0, 32.5 and 43.9% in diuretic, β -blocker, calcium antagonist and ACE inhibitor groups, respectively. Equivalence between the treatments could not be concluded, although analysis with a larger equivalence interval showed that some comparisons indicated equivalence. Significant improvement in satisfaction was observed for certain items for subjective quality of life at 1 month in the calcium antagonist treatment group, and significant differences in the responses to the clinical safety questionnaire were observed after 1-month follow-up in calcium antagonist and β-blocker groups. Differences were no longer significant after 9 months.
These results do not provide evidence on the basis of efficacy of blood pressure lowering or ability to increase short-term (1-year) safety and quality of life favouring any particular treatment among the studied drugs for newly diagnosed patients with mild-to-moderate hypertension.