Osteoporosis treatment prevents hip fracture similarly in both sexes: the FOCUS observational study.

ABSTRACT

Randomized trials have not been performed, and may never be, to determine if osteoporosis treatment prevents hip fracture in men. Addressing that evidence gap, we analyzed data from an observational study of new hip fractures in a large integrated healthcare system to compare the reduction in hip fractures associated with standard-of-care osteoporosis treatment in men versus women. Sampling from 271 389 patients age ≥ 65 who had a hip-containing computed tomography scan during care between 2005-2018, we selected all who subsequently had a first hip fracture (cases) after the CT scan (start of observation) and a sex-matched equal number of randomly selected patients. From those, we analyzed all who tested positive for osteoporosis (DXA-equivalent hip bone mineral density T-score ≤ -2.5, measured from the CT scan using VirtuOst). We defined "treated" as at least six months of any osteoporosis medication by prescription fill data during follow up; "not-treated" was no prescription fill. Sex-specific odds ratios of hip fracture for treated versus not-treated patients were calculated by logistic regression; adjustments included age, BMD T-score, a BMD-treatment interaction, body mass index, race/ethnicity, and seven baseline clinical risk factors. At two-year follow-up, 33.9% of the women (750/2211 patients) and 24.0% of the men (175/728 patients) were treated, primarily with alendronate; 51.3% and 66.3%, respectively, were not-treated; and 721 and 269, respectively, had a first hip fracture since the CT scan. Odds ratio of hip fracture for treated versus not-treated was 0.26 (95% confidence interval 0.21-0.33) for women and 0.21 (0.13-0.34) for men; the ratio of these odds ratios (menwomen) was 0.81 (0.47-1.37), indicating no significant sex effect. Various sensitivity and stratified analyses confirmed these trends, including results at five-year follow-up. Given these results and considering the relevant literature, we conclude that osteoporosis treatment prevents hip fracture similarly in both sexes.

Much evidence suggests that osteoporosis treatment should prevent hip fracture similarly in both sexes. However, because of their expense, randomized clinical trials to demonstrate that definitively have not been performed and may never be. As a result, osteoporosis testing and treatment is not as widely adopted for men as it is for women. Addressing that evidence gap, we analyzed data from over 250 000 patients in the Kaiser Permanente healthcare system in Southern California. Sampling a subset of all patients over a 13-year period who had had a computed tomography (CT or CAT) scan as part of their medical care for any reason, we measured bone mineral density from the CT scans to identify all patients who had osteoporosis at the hip and then used data from the electronic health records to determine statistically the risk of a future hip fracture for those who were treated for osteoporosis versus those who were not treated. We found that the reduction in risk of hip fracture associated with treatment did not differ between the sexes. These results demonstrate that treating osteoporosis in patients at high risk of hip fracture should reduce the risk of hip fracture similarly in both sexes.