Persistance and Compliance with Osteroporosis Therapies Among Women in a Commercially Insured Population in the United States

BACKGROUND: Prior research has shown that rates of persistence and compliance with osteoporosis therapies are associated with significantly fewer vertebral, nonvertebral, and hip fractures. A number of studies have examined medication-taking behavior with oral bisphosphonates and teriparatide, and these 1-year persistence rates have ranged from 39.9% to 56.7%. Limited real-world data are available regarding persistence and compliance rates with newer therapies such as denosumab, a RANK ligand inhibitor administered every 6 months as a subcutaneous injection. OBJECTIVE: To assess persistence and compliance rates over 1 year with newly initiated osteoporosis therapies, including denosumab, alendronate, ibandronate, risedronate, raloxifene, and teriparatide, within a cohort of commercially insured women. METHODS: Health insurance claims data derived from Truven Health Analytics MarketScan Commercial Claims and Encounters and Medicare Supplemental and Coordination of Benefits databases (2010-2013) were used to conduct this retrospective cohort study. Adult females aged 18 years and older newly initiated on denosumab, raloxifene, teriparatide, or oral bisphosphonates (alendronate, ibandronate, or risedronate) between January 1, 2012, and March 31, 2012, were identified for inclusion. The date of the first qualifying osteoporosis prescription claim was defined as the index date. Patients were required to have at least 24 months of pre-index and at least 12 months of post-index continuous enrollment with medical and pharmacy benefits. Outcomes of patients initiating zoledronic acid (administered intravenously once yearly) were not assessed because a 12-month follow-up period would be insufficient for tracking persistence and compliance for this medication. Patients with Paget's disease of the bone, osteogenesis imperfecta, hypercalcemia, malignant cancer and metastasis, human immunodeficiency virus, and patients receiving preventive treatment for risk of breast cancer or denosumab in the pre-index period were excluded from the study. A subcohort of women aged 50 years and older at high risk for fracture (indicated by 1 or more of the following: aged =70 years, a pre-index fracture, or pre-index use of osteoporosis therapy that was discontinued at least 3 months prior to index) was analyzed separately. Propensity score weighting was used to adjust for differences in baseline demographic and clinical characteristics. Persistence, indicated by continuous use of the index therapy without a gap of 60 days or more; medication coverage ratio (MCR), the proportion of days covered by the index therapy; and compliance, defined as an MCR=0.80, were assessed during the 12-month follow-up. Logistic regression was used to estimate the odds of persistence and compliance for the treatment groups of interest. RESULTS: 10,863 female patients newly initiating osteoporosis medications (mean [SD] age: 66.2 [11.5] years) were identified. In the pre-index period, 35.8% of patients had a diagnosis of osteoporosis, while 11.5% had a diagnosis of osteopenia. Pre-index osteoporosis treatment was identified in 29.1% of patients, and 13.6% had an osteoporosis-related fracture in the pre-index period. Propensity score weight-adjusted 12-month persistence with the index medication varied from 28.9% to 35.1% for oral bisphosphonate users, 42.0% for raloxifene users, 59.1% for teriparatide users, and 68.3% for denosumab users (P < 0.0001). The adjusted mean [SD] MCR was highest among patients treated with denosumab (0.83 [0.21]), followed by teriparatide (0.67 [0.31]), raloxifene, (0.57 [0.34]), ibandronate (0.54 [0.32]), alendronate (0.51 [0.33]), and risedronate (0.46 [0.33]; P < 0.0001). The odds of being persistent and compliant across treatments favored denosumab (OR=1.59 to 5.56, P < 0.05 for persistence; OR=2.44 to 7.69, P < 0.0001 for compliance). Results were similar in the subcohort of women aged 50 years and older at high risk for fracture (n=6,187; mean [SD] age: 71.9 [10.9] years). The odds of being persistent and compliant across treatments also favored denosumab (OR=1.62 to 5.75, Pless than 0.0001 for persistence; OR=2.36 to 7.25, Pless than 0.0001 for compliance). CONCLUSIONS: In a U.S. setting, rates of persistence and compliance over 12 months were higher among women initiating denosumab compared with those initiating other osteoporosis therapies. Copyright (C) 2015, Academy of Managed Care Pharmacy. All rights reserved.