SLOW-RELEASE SODIUM-FLUORIDE IN THE MANAGEMENT OF POSTMENOPAUSAL OSTEOPOROSIS - A RANDOMIZED CONTROLLED TRIAL

Objective: To test whether intermittent treatment with slow-release so dium fluoride and continuous calcium citrate supplementation inhibits vertebral fractures without causing fluoride complications. Design:A p lacebo-controlled, randomized trial. Setting: Outpatient setting of sp ecialty clinics in Dallas and Temple, Texas. Interventions: Slow-relea se sodium fluoride (25 mg twice daily) in repeated 14-month cycles (12 months on treatment followed by 2 months off treatment) compared with placebo. Both groups took calcium citrate (400 mg calcium twice daily ) continuously. P Patients: 110 patients with postmenopausal osteoporo sis were randomly assigned to two groups. In the slow-release sodium f luoride group, 48 of 54 patients completed more than 1 cycle of treatm ent (mean, 2.44 cycles/patient), whereas 51 of 56 patients in the plac ebo group completed at least 1 cycle (mean, 2.14 cycles/patient) in th is interim analysis. Measurements: Vertebral fracture rate and lumbar bone mineral content. Vertebral fractures were quantified from yearly radiographs. Bone mass was determined annually by densitometry. Result s: In the sodium fluoride group, the mean L2 to L4 bone mineral conten t increased by 4% to 6% in each cycle and the mean femoral neck bone d ensity increased by 4.1% and 2.1% during the first two cycles, but the radial bone density did not change, The placebo group showed no stati stical change in bane mass at any site. Compared with the placebo grou p, the sodium fluoride group had, a lower individual new vertebral fra cture rate (0.057/patient cycle compared with 0.204/ patient cycle, P = 0.017), a higher fracture-free rate (83.3% compared with 64.7%, P = 0.042), and a lower group fracture rate (0.085/patient cycle compared with 0.239/patient cycle, P = 0.006). The side-effect profile was simi lar for the two groups; no patient developed microfractures, hip fract ures, or blood loss anemia. s Conclusions: Intermittent slow-release s odium fluoride plus continuous calcium citrate, administered for about 2.5 years, inhibits new vertebral fractures, increases the mean spina l bone mass without decreasing the radial shaft bone density, and is s afe to use.