Association between teriparatide adherence and healthcare utilization and costs in real-world US kyphoplasty/vertebroplasty patients

Abstract

The objective of this study was to examine the association between teriparatide adherence and healthcare utilization and costs in real-world US kyphoplasty/vertebroplasty (KV) patients. Among KV patients newly initiating teriparatide, significantly increased pharmacy costs associated with high teriparatide adherence were offset by significantly lower inpatient utilization and medical costs. This study seeks to examine the association between teriparatide adherence and healthcare utilization/costs in real-world US KV patients. Identified patients from a large US administrative claims database were aged 50+ with KV from 1/1/2002-12/31/2010 (first observed KV = index). Included individuals had 6+ months of pre-index continuous enrollment and no pre-index teriparatide, cancer, or Paget's disease. Follow-up period for patients initiating teriparatide was ≤36 months post-index. Three teriparatide adherence cohorts were constructed using the proportion of days covered (PDC) during the follow-up period: low (PDC ≤ 0.5), medium (PDC >0.5-≤ 0.8), and high (PDC >0.8). Repeated KV admissions, any inpatient admission, number of inpatient admissions, and per-patient-per-month (PPPM) inpatient, outpatient, pharmacy, and total costs were compared between cohorts. The associations between teriparatide adherence and healthcare utilization/costs were examined using multivariable regression models, adjusting for patient demographics and clinical characteristics. Included were 1,568 patients (mean age, 75 years; 82% female): 403 (26%) had low adherence, 382 (24%) medium, and 783 (50%) high. After multivariable adjustment, high adherence was significantly associated with the lowest PPPM inpatient (low = $1,287; medium = $1,005; high = $678) and outpatient (low = $1,464; medium = $1,244; high = $1,077) medical costs, but with increased pharmacy costs (low = $752; medium = $1,159; high = $1,616; all P < 0.05), leading to similar total costs (low = $3,344; medium = $3,376; high = $3,351) between cohorts; high adherence was also significantly associated with the lowest odds of repeated KV admission, any inpatient admission, and number of inpatient admissions (all P < 0.05). Among KV patients initiating teriparatide, significantly increased pharmacy costs associated with high teriparatide adherence were offset by significantly lower inpatient utilization and medical costs.