Design of the POSSIBLE US™ Study: postmenopausal women's compliance and persistence with osteoporosis medications

Failure to take prescribed medication is common. The POSSIBLE US (TM) study is evaluating the impact of physician and patient characteristics on patient-reported compliance and persistence with osteoporosis medications. We report our study design and the baseline characteristics of 4,994 postmenopausal women recruited from primary care physician offices in 33 states. The Prospective Observational Scientific Study Investigating Bone Loss Experience (POSSIBLE US (TM)) is a longitudinal cohort study of osteoporosis therapy in primary care. Between 2004 and 2007, 134 physicians (in 33 states) enrolled postmenopausal women initiating, changing, or continuing osteoporosis medications. After completing a baseline questionnaire, participants will provide data semi-annually for up to 3 years through 2008. Physicians provide patient data at baseline and routine follow-up visits. Participants from 23 sites also signed a release regarding administrative claims data for economic analyses and validation of self-reported data. Four thousand nine hundred and ninety-four evaluable women were recruited from internal medicine (n = 1,784), family practice (n = 1,556), obstetrics/gynecology (n = 1,556), and from one rheumatology practice (n = 98). Mean participant age was 64.3 years (SD = 9.97); 89% were Caucasian; 59% had some college education. Sixty-three percent used a single osteoporosis agent, usually a bisphosphonate. For monotherapy patients, concordance between clinic- and patient-reported medication use was lowest for patients prescribed estrogen therapy (70%) or calcium/vitamin D (72%). Obstetrician/gynecologists enrolled younger women, who were more likely to use estrogen therapy than patients enrolled by other physicians. The 934 women (19%) prescribed only calcium/vitamin D were younger than women prescribed pharmacologic therapy. POSSIBLE US (TM) provides a unique foundation for evaluating longitudinal use of osteoporosis medications and related outcomes.