Anti-osteoporotic medication discontinuation and switching among new bisphosphonate users at the end of 12 months of follow up. Discontinuation definition I: Totally discontinued all anti-osteoporosis drugs as of the end of follow up. The total percentage of discontinuation I at the 12 months of follow-up is 38%. Discontinuation definition II: Totally discontinued all anti-osteoporosis drugs as of the end of follow up, or switched to another anti-osteoporosis medication, or stopped then restarted the same anti-osteoporosis drugs. The total percentage of discontinuation II at the 12 months of follow-up is 52%. As permitted N (CMS does not allow reporting of N < 11). Alendronate, risedronate, ibandronate, zoledronic acid, calcitonin, raloxifene, teriparatide were considered as different anti-osteoporosis medications. Branded and generic alendronates were considered as the same medication.