There is indeed much less evidence on the effectiveness of bisphosphonates for women older than 80 years of age than for younger women. A trial of alendronate in elderly women in long-term care facilities (mean age, 78.9 years; range, 65 to 91 years) reported increased bone density at the spine and hip (1). Two analyses from the Fracture Intervention Trial (FIT) of alendronate indicated fracture benefit for older women. After an average of 2.9 years of follow-up, the relative risk for new vertebral fractures was 0.49 (95% CI, 0.35 to 0.68) for women younger than 75 years of age and 0.62 (CI, 0.41 to 0.94) for women 75 years of age and older. There was no apparent interaction between treatment and age (P > 0.2) (2). Risks for other clinical fractures were also reduced in both groups, although the CI crossed 1.0 for older women. Another analysis of FIT data after 4.3 years of follow-up indicated that the effect of alendronate on the incidence of multiple fractures was not affected by age (<75 years of age vs. 75 years of age) (3).

A large trial of risedronate indicated a significant reduction in hip fractures for women ages 70 to 79 years (relative risk, 0.6 [CI, 0.4 to 0.9]), but not for those 80 years of age and older (relative risk, 0.8 [CI, 0.6 to 1.2]) (4). However, the older women were selected by age and risk factor criteria, and bone density measurements were available for only 31%. Women 80 years of age and older in this study may not be comparable to women 70 to 79 years of age, who were selected by bone density criteria and had mean femoral neck T-scores of –3.7.

Although data are limited for women older than 80 years of age and interpretations may vary, the available data suggest possible benefit for older women with low bone density. Trials of other interventions, such as calcium and vitamin D supplementation and use of external hip protectors, indicate fracture benefit in appropriate candidates. However, trials of strength and balance training, improving vision problems, reducing fall hazards, and other similar interventions are lacking and were not reviewed in our evidence report on screening for postmenopausal osteoporosis. Factors besides low bone density, such as changes in bone connective tissue and functional frailty, become increasingly important for fractures as women age. A thorough clinician will consider multiple clinical factors when assessing an elderly woman for fracture risk and will design an individual management plan that may or may not include medical therapies.