Despite Mortality Risk, Women Over 80 With Osteoporosis Have High 5-Year Risk of Hip Fracture

Women 80 years or older with osteoporosis, including those with multiple comorbidities and poor prognosis, have a high 5-year probability of hip fracture even when accounting for competing mortality risk, according to new study findings published in JAMA Internal Medicine.

In contrast, for women without osteoporosis who are still at a high risk of fracture, mortality risk far outweighs the probability of hip fracture, especially among those with more comorbidities and worse prognosis.

Researchers determined these findings from more than 1500 treatment-naïve women with osteoporosis or without osteoporosis but at high fracture risk due to the presence of osteopenia and a 10-year predicted fracture probability at or above Fracture Risk Assessment Tool intervention thresholds proposed by the National Osteoporosis Foundation.

The findings showed that when taking into account the competing risk of mortality, the 5-year hip fracture probability was more than 3-fold higher among women with osteoporosis compared with women without osteoporosis (13% vs 4%).

This difference in hip fracture probability was even more drastic as comorbidities increased and prognosis worsened. Despite having similar probabilities of mortality (36.1% vs 34.4%), the presence of 3 comorbidities was associated with a hip fracture probability of 18.1% among women with osteoporosis compared with 2.5% among women without osteoporosis.

“While advanced age is associated with lower rates of drug treatment to prevent fracture, the estimated 5-year fracture risk is high among women 80 years and older, with probabilities ranging from 7.1% among those 80 to 84 years up to 20.9% among those 90 years and older,” explained the authors of the study, who wrote that their findings suggest that initiation of drug treatment among the patient population may still be effective to prevent hip fracture.

Among the women, who were enrolled in the Study of Osteoporotic Fracture, there were 761 with osteoporosis and 767 without. During a mean follow-up of 4.4 years, 125 (8.8%) of the 1528 women experienced a hip fracture (95 with osteoporosis and 30 without), and 287 died before experiencing this outcome (150 with osteoporosis and 137 without).

The 5-year probability of mortality was 24.9% among women with osteoporosis and 19.4% among women without osteoporosis. More comorbidities and poorer prognosis were associated with increasing probability of mortality for both groups of women.

Based on these findings, the researchers wrote that the absolute benefit of drug treatment to prevent hip fracture is likely to be significantly less for women without osteoporosis because the probability of death greatly outweighed the probability of hip fracture, especially among those with more comorbidities and poorer prognosis.

Reference

Ensrud K, Kats A, Boyd C, et al. Association of disease definition, comorbidity burden, and prognosis with hip fracture probability among late-life women [published online June 17, 2019]. JAMA Intern Med. doi: 10.1001/jamainternmed.2019.0682