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Zoledronic acid prevents fractures in men with osteoporosis

BMJ 2012; 345 doi: http://dx.doi.org/10.1136/bmj.e7471 (Published 06 November 2012) Cite this as: BMJ 2012;345:e7471

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Zoledronic acid, a bisphosphonate given intravenously at a dose of 5 mg once a year, may reduce the risk of morphometric vertebral fractures in men by 67% compared with placebo. Morphometric fractures are identified by a change in shape of a bone, rather than from pain or other symptoms. About 40% of osteoporotic fractures in people over 50 years occur in men, yet until now trials that that have included men have lacked clinical outcomes and only examined surrogates such as bone mineral density.

The two year placebo controlled trial looked at 1199 men aged 50-85 years, of whom three had hypogonadism and the rest had primary osteoporosis. All were given daily calcium and vitamin D supplements.

The primary outcome—one or more new morphometric vertebral fracture over 24 months—was seen in 4.9% (28/574) of men who took placebo versus 1.6% (9/553) of men given zoledronic acid (relative risk 0.33, 95% CI 0.16 to 0.70). Similar results were seen for the secondary outcome—one or more new morphometric vertebral fractures over 12 months (2.8% v 0.9% for placebo and the tested drug, respectively; 0.32, 0.12 to 0.88).

At two years, zoledronic acid reduced the risk of moderate to severe morphometric vertebral fractures by 63% (P=0.03); prevented changes in height (−2.2 v −4.5 mm with placebo; P=0.002); and improved surrogate markers such as bone mineral density at the lumbar spine, total hip, and femoral neck (P<0.05 for all). Clinically evident fractures were also less common with zoledronic acid, but this wasn’t significant (1% v 1.8% of men taking placebo; hazard ratio 0.6, 0.2 to 1.5).

Adverse events were seen in nine tenths of men given zoledronic acid and three quarters of men given placebo, most commonly fever, pain in joints and muscles, and headache. Nine men (1.5%) allocated zoledronic acid had a heart attack, compared with two men (0.3%) given placebo (P<0.05); the researchers deemed these events unrelated to the study drug.

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Cite this as: BMJ 2012;345:e7471