American Board of Internal Medicine (ABIM) Certification Practice Exam

Which antihypertensive has been found to reduce the risk of hip and pelvic fractures compared with other antihypertensives?

1. Amlodipine

2. Chlorthalidone

3. Lisinopril

4. Hydrochlorothiazide

The correct answer is: Chlorthalidone

Chlorthalidone is the antihypertensive that has been associated with a reduction in the risk of hip and pelvic fractures compared to other antihypertensives. This benefit is largely attributed to the drug's diuretic properties, which can lead to favorable changes in calcium metabolism and bone mineral density. Epidemiological studies and clinical trials have suggested that thiazide diuretics like chlorthalidone may help to mitigate bone loss and promote bone health, thereby reducing the incidence of fractures in older adults, particularly in those at risk for osteoporosis or similar conditions. In contrast, while amlodipine, lisinopril, and hydrochlorothiazide are effective antihypertensives, there is no strong evidence to suggest that they provide a similar protective effect against fractures. Amlodipine, a calcium channel blocker, primarily works by vascular smooth muscle relaxation, while lisinopril, an ACE inhibitor, focuses on lowering blood pressure through the renin-angiotensin-aldosterone system. Hydrochlorothiazide, though a thiazide diuretic like chlorthalidone, has not consistently shown the same fracture risk reduction in studies. Therefore, chlorthalidone stands out for its additional benefits