The effect of raloxifene therapy on the risk of new clinical vertebral fractures at three and six months: a secondary analysis of the MORE trial.

Objective: Raloxifene treatment (60 mg/day) significantly decreases the risk of new clinical vertebral fractures by 68% at 1 year compared with placebo. The objective of the present analysis is to evaluate the effects of raloxifene on the incidence of new clinical vertebral fractures at 3 and 6 months after initiation of treatment.

Research Design And Methods: A double-blind, randomized, placebo-controlled, 4-year Multiple Outcomes of Raloxifene Evaluation (MORE) trial was conducted in 180 study centers. Postmenopausal women with osteoporosis (N = 7705) were randomized to placebo, or raloxifene at 60 or 120 mg/day.

Main Outcome Measures: Vertebral radiographs were obtained when patients reported symptoms suggestive of vertebral fracture at or between clinic visits, which were held at 3 and 6 months, and every 6 months thereafter. If a new adjudicated fracture was found, this was considered as a clinical vertebral fracture. The analyses included all randomized patients with a baseline and at least one follow-up radiograph (n = 6828).

Results: One woman treated with raloxifene 60 mg/day (n = 2259) and 10 in the placebo group (n = 2292) had a clinical vertebral fracture in the first 6 months, resulting in a 90% relative risk (RR) reduction [RR 0.10 (95% CI 0.01, 0.63)] and a 0.39% absolute risk reduction (ARR). Similar results were observed with raloxifene 120 mg/day at 6 months. When the raloxifene groups were pooled, a significant (p = 0.034) decrease in clinical vertebral fracture risk [RR 0.20 (95% CI 0.03, 0.90), ARR 0.17%] was seen as early as 3 months.

Conclusion: The risk of new clinical vertebral fractures was reduced after 3 or 6 months of raloxifene.