A Cochrane review 1 included 119 studies, of which 102 provided data for quantitative synthesis. 34 studies (n=15,188) were classified as primary prevention studies and 68 studies (n=29,577) as secondary prevention. A study was classified as secondary prevention if its population met one or more of the following hierarchical criteria: a diagnosis of osteoporosis, a history of vertebral fractures, a low bone mineral density T-score (-2.5 or lower), and 75 years old or older. If a study population met none of those criteria, it was classified as a primary prevention study.
16 primary prevention studies (1 to 5 years in length, n=10,057) and 20 secondary prevention studies (1 to 3 years in length, n=7,375) compared alendronate 10 mg/day (or 70 mg/week) to placebo, no treatment, or both. Primary prevention: Alendronate reduced clinical vertebral fractures (RR 0.45, 95% CI 0.25 to 0.84; 6 studies, n=2,116) and non-vertebral fractures (RR 0.83, 95% CI 0.72 to 0.97; 7 studies, n=7,213). No differences were observed for hip fractures (RR 0.76, 95% CI 0.43 to 1.32; 7 studies, n=7,299), wrist fractures (RR 1.12, 95% CI 0.84 to 1.49; 8 studies, n=7,477), withdrawals due to adverse events (RR 1.03, 95% CI 0.89 to 1.18; 14 studies, n=8,351), and serious adverse events (RR 1.08, 95% CI 0.82 to 1.43; 6 studies, n=2,619). Secondary prevention: Alendronate reduced clinical vertebral fractures (RR 0.45, 95% CI 0.28 to 0.73; 2 studies, n=2,169), non-vertebral fractures (RR 0.80, 95% CI 0.64 to 0.99; 3 studies, n=2,235), hip fractures (RR 0.49, 95% CI 0.25 to 0.96; 5 studies, n=2,663), wrist fractures (RR 0.54, 95% CI 0.33 to 0.90; 3 studies, n=2,191), and serious adverse events (RR 0.75, 95% CI 0.59 to 0.96; 9 studies, n=2,312). No differene in withdrawals due to adverse events was observed (RR 0.95, 95% CI 0.78 to 1.16; 18 studies, n=4,971). No cases of osteonecrosis of the jaw and atypical femoral fracture were observed.
The following decision support rules contain links to this evidence summary: