Common Questions
What is the number needed to treat (NNT) with alendronate to prevent one clinical osteoporotic fracture?
The NNT depends on the drug's ability to reduce fractures, as well as on the baseline risk without treatment (1,2). Thus, the number will vary based on the case scenario.
| Postmenopausal Women Without Prior Vertebral Fracture | |
|---|---|
| T-score < -2.5 | NNT = 15 |
| T-score < -2.0 | NNT = 20 |
| T-score -1.6 to -2.0 | NNT > 500 |
| Postmenopausal Women with Prior Vertebral Fractures and T-score < -2.0 | |
| One prior vertebral fracture | NNT = 40 |
| Two or more prior vertebral fractures | NNT = 10 |