Original Full Length Article Association between teriparatide adherence and healthcare utilization and costs among hip fracture patients in the United States Yang Zhao a, ⁎ ,1 , Stephen S. Johnston b , David M. Smith b , Donna McMorrow b , John Krege a , Kelly Krohn a a Eli Lilly and Company, 893 S. Delaware St., Indianapolis, IN 46285, USA b Truven Health Analytics, 7700 Old Georgetown Rd., Ste 650, Bethesda, MD 20814, USA abstract article info Article history: Received 29 May 2013 Revised 2 December 2013 Accepted 11 December 2013 Available online 18 December 2013 Edited by: Robert Recker Keywords: Hip fracture Teriparatide Adherence Cost Utilization Purpose: This study examined the association between teriparatide (TPTD) adherence, and healthcare utilization and costs among hip fracture (HFx) patients. Methods: Individuals aged 50 years and older with an HFx between 1/1/2002-12/31/2010 were identified from a large US administrative claims database. The first HFx date during this period was designated as the index. Selected patients had at least 6 months of pre-index continuous enrollment (baseline) and no baseline TPTD use, cancer, or Paget's disease. Patients initiating TPTD post-index were followed until censoring at switch to bisphosphonates, disenrollment, 36 months post-index, or diagnosis of cancer or Paget's disease. Teriparatide adherence was mea- sured as the proportion of days covered (PDC) by TPTD prescriptions, during the follow-up period, to construct three adherence groups: low (PDC ≤ 0.5), medium (0.5 b PDC ≤ 0.8), and high (PDC N 0.8) adherence. Outcome measures were repeated HFx, number of inpatient admissions, and per-patient-per-month (PPPM) healthcare costs. Multivariable generalized linear models examined the association between the TPTD adherence groups and the outcomes, adjusting for cross-group differences in patient characteristics. Results: A total of 824 patients (mean age 75 years, 90% female) were included: 30% low, 27% medium, and 44% high adherence. In multivariable analyses, high adherence was significantly (all p b 0.05) directly associated with increased PPPM pharmacy costs ($621 low, $1093 medium, and $1572 high), but also with the lowest inpa- tient ($963 low, $960 medium, and $629 high) and outpatient ($1087 low, $1068 medium, and $776 high) costs, leading to the highest total costs in the medium adherence group but similar costs in the high and low adherence groups ($2599 low, $3163 medium, and $2869 high). The high adherence group also had the lowest number of inpatient admissions. Conclusions: Significantly increased pharmacy costs associated with the high TPTD adherence group were offset by significantly fewer inpatient admissions, fewer repeated HFx, and lower inpatient and outpatient costs. © 2013 Elsevier Inc. All rights reserved. Introduction Osteoporosis is a major health threat for more than half of the United States (US) population over the age of 50, or approximately 44 million people [1], and is characterized by reduced bone mineral density (BMD), deterioration in bone microstructure, and increased risk of frac- ture [2]. Osteoporosis is the primary underlying cause of fractures in the elderly, and it contributes to more than 1.5 million fractures each year in the affected US population [3]. Estimated to exceed $25 billion by 2025, direct medical costs associated with osteoporosis have been esti- mated between $13.7 and $20.3 billion in the US in 2005 [4]. Hip frac- tures (HFx), one of the three most common fractures associated with osteoporosis [5], are a major health problem because of their high fre- quency and associated costs [5,6]. Approximately 330,000 HFx occur an- nually in the US [7]. The 2013 National Osteoporosis Foundation (NOF) guidelines rec- ommend that postmenopausal women and men over the age of 50 with a fracture undergo BMD testing, spine imaging, and evaluation for pharmacologic osteoporosis treatment to decrease future fracture risk [2]. Currently, in the US, the treatment of osteoporosis includes ral- oxifene, oral and intravenous bisphosphonates, teriparatide (TPTD), denosumab, estrogen, and calcitonin [8]. According to NOF guidelines, to reduce the risk of fracture, physicians should encourage patients to practice compliance with their osteoporosis therapies [2]. Several stud- ies have examined the roles of adherence (which has been defined as the extent to which patients take their medication as prescribed [9,10]) and persistence (which has been defined as the duration of Bone 60 (2014) 221–226 Abbreviations: AIR, adjusted incidence ratio; BMD, bone mineral density; COBRA, Consolidated Omnibus Budget Reconciliation Act; Deyo-CCI, Deyo-Charlson Comorbidity Index; DXA, dual X-ray absorptiometry; GLM, generalized linear model; HFx, hip frac- ture(s); HIPAA, Health Insurance Portability and Accountability Act; IRB, Institutional Review Board; NOF, National Osteoporosis Foundation; PDC, proportion of days covered; PPPM, per-patient-per-month; TPTD, teriparatide; US, United States. ⁎ Corresponding author at: Novartis Pharmaceuticals Corporation, One Health Plaza, East Hanover, NJ, 07936–1080, USA. E-mail address: yang-3.zhao@novartis.com (Y. Zhao). 1 Present Address: Novartis Pharmaceuticals, One Health Plaza, East Hanover, NJ, 07936, USA. 8756-3282/$ – see front matter © 2013 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.bone.2013.12.016 Contents lists available at ScienceDirect Bone journal homepage: www.elsevier.com/locate/bone