A 3-year postmarketing study on the safety and effectiveness of once-monthly risedronate in Japanese patients with osteoporosis

OBJECTIVES: This postmarketing study aims to evaluate the safety and effectiveness of oral administration of risedronate at 75 mg once monthly for 36 months in patients with osteoporosis in Japan. METHODS: Participants were ambulatory outpatients with osteoporosis who were ≥ 50 years old and had prevalent vertebral fractures. Outcomes were the incidence rate of adverse drug reaction (ADR), cumulative incidence of vertebral, nonvertebral, and hip fractures, the percent changes of lumbar spinal L(2–4) bone mineral density (BMD), and low back pain. In addition, medication compliance was examined. RESULTS: Safety, vertebral fractures, and other outcomes were analyzed in 542, 328, and 535 patients, respectively. In the safety analysis set, 88.38% of the patients were women and the mean age was 75.9 years. The monthly medication compliance rate ranged from 83.24% to 95.38%. The incidence rate of ADRs, including 4 severe ADRs, was 10.52% (n = 57). The common ADRs were gastrointestinal disorders, musculoskeletal, and connective tissue disorders. No osteonecrosis of the jaw was reported. The cumulative incidences (95% CI) of vertebral, nonvertebral, and hip fractures at 36 months were 12.58% (8.61–18.18), 6.59% (4.31–10.01), and 1.58% (0.64–3.88), respectively. The L(2–4) BMD increased by 10.59% compared with baseline value (P < 0.01), and the proportion of patients with low back pain decreased to 30.77%, at 36 months. CONCLUSIONS: Administering 75 mg of risedronate once a month remains a favorable compliance rate and may be useful for the treatment of patients, even the elderly, with osteoporosis in daily practice.