Balancing fracture risk versus risk of mortality before fracture among women aged 80 years or older

Background: Most fractures occur in women aged ≥80 years but competing mortality unrelated to fracture may limit the benefit of osteoporosis drug therapy for some women in late life. Our primary aim was to develop separate prediction models for non-spine fracture (NSF) and mortality before fracture to identify subsets of women with varying fracture versus mortality risks. Methods: Separate prediction models were developed for NSF and mortality before NSF for 4895 women aged ≥80 years enrolled in the Study of Osteoporotic Fractures (SOF) or the Health Aging and Body Composition (HABC) study. Proportional hazards models modified to account for competing mortality were used to identify candidate risk factors for each outcome. Predictors associated with NSF or mortality (p < 0.2) were included in separate competing risk models to estimate the cumulative incidence of NSF and mortality before NSF during 5 years of follow-up. This process was repeated to develop separate prediction models for hip fracture and mortality before hip fracture. Results: Significant predictors of NSF (race, total hip BMD, grip strength, prior fracture, falls, and use of selective serotonin reuptake inhibitors, benzodiazepines, or oral/transdermal estrogen) differed from predictors of mortality before NSF (age, walking speed, multimorbidity, weight change, shrinking, smoking, self-rated health, dementia, and use of warfarin). Within nine subsets of women defined by tertiles of risk, 5-year outcomes varied from 28% NSF and 8% mortality in the high-risk NSF/low-risk mortality subset, to 9% NSF and 22% mortality in the low-risk NSF/high-risk mortality subset. Similar results were seen for predictors of hip fracture and mortality before hip fracture. Conclusion: Considerable variation in 5-year competing mortality risk is present among women in late life with similar 5-year NSF risk. Both fracture risk and life expectancy should inform shared clinical decision-making regarding initiation or continuation of osteoporosis drug therapy for women aged ≥80 years.