Association between screening for osteoporosis and the incidence of hip fracture

Background: Because direct evidence for the effectiveness of screening is lacking, guidelines disagree on whether people should be screened for osteoporosis. Objective: To determine whether population-based screening for osteoporosis in older adults is associated with fewer incident hip fractures than usual medical care. Design: Nonconcurrent cohort study. Setting: Population-based cohort enrolled in the Cardiovascular Health Study (CHS) from 4 states (California, Pennsylvania, Maryland, and North Carolina). Patients: 3107 adults 65 years of age and older who attended their CHS study visits in 1994-1995. Measurements: 31 participant characteristics (including demographic characteristics, medical histories, medications, and physical examination findings) and incident hip fractures over 6 years of follow-up. Intervention: Bone density scans (dual-energy x-ray absorptiometry [DEXA] at the hip) for participants in California and Pennsylvania (n = 1422) and usual care for participants in Maryland and North Carolina (n = 1685). Results: The incidence of hip fractures per 1000 person-years was 4.8 in the screened group and 8.2 in the usual care group. Screening was associated with a statistically significant lower hazard of hip fracture than usual care after adjustment for sex and propensity to be screened (Cox proportional hazard ratio, 0.64 [95% CI, 0.41 to 0.99]). Limitations: The mechanism of the association was unclear. A small unmeasured confounder that decreased the hazard of hip fracture could diminish or erase the observed association. Conclusions: Use of hip DEXA scans to screen for osteoporosis in older adults was associated with 36% fewer incident hip fractures over 6 years compared with usual medical care. Further research is needed to explore the mechanism of this association.