Association between teriparatide adherence and healthcare utilization and costs among hip fracture patients in the United States

Abstract

PurposeThis study examined the association between teriparatide (TPTD) adherence, and healthcare utilization and costs among hip fracture (HFx) patients. MethodsIndividuals aged 50years 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 6months 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, 36months post-index, or diagnosis of cancer or Paget's disease. Teriparatide adherence was measured 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<PDC≤0.8), and high (PDC>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. ResultsA total of 824 patients (mean age 75years, 90% female) were included: 30% low, 27% medium, and 44% high adherence. In multivariable analyses, high adherence was significantly (all p<0.05) directly associated with increased PPPM pharmacy costs ($621 low, $1093 medium, and $1572 high), but also with the lowest inpatient ($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. ConclusionsSignificantly 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.