Objectives: Our primary objective was to describe the prevalence of osteoporosis (OP) diagnosis in nursing home residents (NHRs). Secondary objectives included assessment of pharmacologic therapies and risk of fracture in NHRs with OP, as well as differentiating clinical characteristics of treated versus untreated male and female NHR with OP. Finally, we sought to evaluate persistence and compliance rates in NHRs treated with OP and determine the prevalence of severe renal impairment in NHRs with OP treated with a bisphosphonate. Design: Retrospective cohort analysis. Setting: US NH. Participants: NHRs with a Minimum Data Set (MDS) 3.0 record in the Omnicare Senior Health Outcomes (OSHO) data repository during the time period of October 1, 2011, to September 30, 2012. Measurements: A patient was considered to have an OP diagnosis if MDS item I3800 indicated the NHR had OP or if the MDS record contained ICD-9-CM codes 733.0x. An expanded definition of OP diagnosis was explored, in which an NHR with a previous fracture (MDS items I3900, I4000, J1700C = 1) was also considered to have OP. OP pharmacologic therapies were extracted from the pharmacy claims data and included alendronate, calcitonin salmon, denosumab, ibandronate, raloxifene, risedronate, and teriparatide. Using MDS items, cognitive impairment (Brief Instrument for Mental Status, Cognitive Performance Scale) and functional impairment (composite activities of daily living) were assessed. Using MDS and prescription claims data, high risk of fracture (at least 2 of the following: age >= 75 years, female gender, previous fracture, history of falls, and use of a bisphosphonate) was assessed. Persistence was indicated by continuous use of therapy without a gap of more than 60 days, compliance was calculated using the medication possession ratio, and creatinine clearance (Clcr) was calculated using a modified Cockcroft-Gault equation. Results: The prevalence of OP in NHRs was 13.5%. Using the expanded OP definition, the prevalence of OP increased to 24.2%. Among NHRs with OP (n - 23,666), the mean age was 82.5 and 85.1% were female; 36.8% had gastroesophageal reflux disease or ulcer. Per the definition of high risk for fracture based on older age, female gender, prior fracture, fall history, and use of bisphosphonates, 89.0% of NHRs with OP met the criteria. Additionally, 10.8% had hip fracture, and 15.8% had other fracture. Overall, few NHRs with OP received active treatment: one-third received pharmacologic therapy, of which 73.5% received an oral bisphosphonate. Those with a history of hip fracture had similar treatment rates (31.7%) to those without (32.0%) (P = .804), whereas those with a history of other fracture were more likely to be treated (35.9%) than those without (31.2%) (P = .001). Two-thirds of residents with OP had moderate/severe cognitive impairment, and these residents were less likely to receive OP therapy than those without (P = .001). Persistence with pharmacologic therapy in NHR with a full year of pharmacy data (n = 1399) was higher for raloxifene (82.9%), with calcitonin salmon and bisphosphonates being similar, and the few NHRs who received teriparatide and denosumab were lower. Of the NHRs who received bisphosphonates for whom there was creatinine clearance data, 57% had a Clcr lower than 35 mL/min. Conclusion: The recognized prevalence of OP in NHRs using MDS records was low, but consistent with previous reports. Among those with a documented diagnosis of OP, approximately 89% of NHRs with OP were at high risk of fracture and only one-third were treated with active pharmacologic therapy. For those treated, persistence and compliance was suboptimal, but higher with oral therapies. More than half of NHRs with OP treated with bisphosphonates had Clcr of less than 35 mL/min, suggesting alternative forms of therapy should be considered. For all of these reasons, the opportunity exists to improve the care and medication use of residents with OP who are at high risk of fracture. (C) 2015 AMDA - The Society for Post-Acute and Long-Term Care Medicine.