Table 5. Screening for Osteoporosis in 10,000 Postmenopausal Women1

Hip and Vertebral Fracture Outcomes by 5-year Age Intervals

Variable Age Group
50-54 y 55-59 y 60-64 y 65-69 y 70-74 y 75-79 y
Base Case Assumptions2 Prevalence of osteoporosis 0.0305 0.0445 0.065 0.120 0.2025 0.285
Relative risk for hip fracture with treatment 0.63 0.63 0.63 0.63 0.63 0.63
Relative risk for vertebral fracture with treatment 0.52 0.52 0.52 0.52 0.52 0.52
Adherence to treatment 0.7 0.7 0.7 0.7 0.7 0.7
Results Identified as high-risk (osteoporotic) 305 445 650 1,200 2,025 2,850
Hip fractures prevented 1 2 5 14 39 70
NNS to prevent 1 hip fracture 7,446 4,338 1,856 731 254 143
NNT to prevent 1 hip fracture 227 193 121 88 51 41
Vertebral fractures prevented 5 7 22 40 95 134
NNS to prevent 1 vertebral fracture 1,952 1,338 458 248 105 75
NNT to prevent 1 vertebral fracture 60 60 30 30 21 21

1NNS = number needed to screen for benefit; NNT = number needed to treat.
2Estimates for assumptions include age-specific prevalence rates for osteoporosis and probabilities of fractures; relative risk of 0.63 for hip fractures and 0.52 for vertebral fractures with treatment; treatment adherence of 0.7 (see text).

Formulas for calculations are described in Appendix Table 2.

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