A class of drugs called thiazides, a diuretic, is recommended as the first choice of treatment for high blood pressure (hypertension). However, some clinicians have hesitated to use thiazide diuretics like chlorthalidone to treat hypertension. This is because they are associated with a 15 to 30 percent greater risk of developing diabetes in comparison to treatment with an angiotensin converting enzyme (ACE) inhibitor, such as lisinopril, or a calcium channel blocker like amlodipine.
Results of a new study: comparing three common blood pressure-lowering drugs
A new publication in the journal Circulation compares the risks for cardiovascular disease (CVD) when treating hypertension with one of three drugs: chlorothiazide, lisinopril, or amlodipine. This comparison is from a long-term follow-up of the clinical research trial, “Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial” (ALLHAT).
The results confirmed that diabetes did develop more frequently in people taking chlorthalidone than with the other two antihypertensive drugs. Also, new-onset diabetes raised the risk of coronary heart disease (CHD) by 50 percent. Nonetheless, the use of chlorthalidone was associated with a lower long-term risk of death from CHD, stroke, heart failure, or other cardiovascular disease than treatment with lisinopril or amlodipine. Thus, the results suggest that thiazide-induced diabetes has less long-term adverse impact on cardiovascular disease than the new onset of diabetes that develops with other antihypertensive drugs.
Bottom line: the risks should not deter the use of thiazides
The authors of the report state that “the risk of diabetes associated with chlorthalidone should not deter clinicians from using it long-term.”
Thiazides are less expensive than the other antihypertensive medications and are usually taken once a day. In many people, however, more than one antihypertensive drug is required to achieve adequate control of blood pressure.
Recognition that statins also raise the likelihood of developing diabetes probably means that a similar long-term study is needed to determine whether statin-induced diabetes increases the risk of cardiovascular disease.