The impact of teriparatide adherence and persistence on fracture outcomes.

UNLABELLED: The study investigated the real-world relationship between teriparatide adherence and persistence and fracture outcomes in a US claims database. Fracture risk was estimated to decrease as adherence and persistence increased for any clinical, vertebral, and non-vertebral fractures. Greater emphasis on programs to increase patient adherence may improve clinical outcomes.

INTRODUCTION: Adherence to osteoporosis treatment is essential for achieving optimal therapeutic outcomes. Previous findings from clinical trials and observational studies demonstrate that longer teriparatide (TPTD) exposure is associated with fewer fractures. The study aim was to investigate real-world relationships between TPTD adherence and persistence and fracture outcomes.

METHODS: The Thomson Reuters MarketScan® database, 2004-2008, was used to identify TPTD users with continuous enrollment 12 months pre- and 24 months post-TPTD initiation. Post-index fractures included vertebral and non-vertebral. Adherence (medication possession ratio, MPR) groups were defined as high (MPR ≥ 0.80), medium (0.5 ≤ MPR < 0.8), and low (MPR < 0.5). Persistence groups were defined by periods 1-6, 7-12, 13-18, and 19-24 months. Logistic regressions modeled fracture risk for any clinical, hip, vertebral, and non-vertebral fractures, controlling for patient characteristics, insurance and healthcare provider types, Charlson comorbidity index, bone mineral density screening, medication use, and fracture history.

RESULTS: Among 3,587 TPTD patients (mean age 68.9 years; 91% female), fracture risk was lowest in high MPR patients in all models except hip (OR = 1.17; p = 0.64). Medium versus high MPR was a significant risk factor for any fracture (OR = 1.49; p = 0.004) and non-vertebral fracture (OR = 1.45; p = 0.014); low-MPR was a significant risk factor for any fracture (OR = 1.64; p < 0.01), vertebral fracture (OR = 2.56; p = 0.001), and non-vertebral fracture (OR = 1.44; p = 0.013). Persistence of 1-6 months versus 19-24 months was associated with higher risk for any clinical (OR = 1.88, p < 0.001), vertebral (OR = 3.69; p < 0.001), and non-vertebral fracture (OR = 1.51; p = 0.011), but not hip (OR = 1.93; p = 0.08).

CONCLUSIONS: Fracture risk decreased as TPTD adherence and persistence increased for any clinical, vertebral, and non-vertebral fractures.