To compare low-dose thiazides to β-blockers, angiotensin converting enzyme (ACE) inhibitors, calcium antagonists and α-blockers for simplicity, tolerability, efficacy, safety and cost-effectiveness as first-line treatment for hypertension.
Review of short-term comparative studies, and the outcome of long-term trials with vascular complications of hypertension as endpoints.
Among the advantages of thiazides are a flat dose-reponse; no dose titration; effectiveness when used once a day; no first-dose hypotension; and few contra-indications.
Thiazides are the best tolerated agents in patients over the age of 60 years and in younger women. They sometimes cause gout and impotence in younger men, in whom β-blockers are equally acceptable first-line therapy.
Thiazide-based regimens have consistently reduced vascular complications of hypertension, the real measure of efficacy. There is little evidence that regimens based on other drugs are effective in this sense.
Concerns that thiazide-induced biochemical changes cause coronary events are baseless. An overview of outcome trials shows that thiazide-based treatment reduces coronary events significantly, and the reduction is not significantly different from that predicted by epidemiological data. Thiazide-based therapy has also reduced coronary events significantly and substantially in elderly patients with isolated systolic hypertension.
Low-dose thiazide treatment needs minimal monitoring, and has proved most cost-effective in formal analyses.
Low-dose thiazide treatment is a clear first-line choice for patients aged over 60 years and younger women, except those with diabetes or gout. In younger men there is little to choose between thiazides and β-blockers.