Cost and Consequences of Nonadherence With Oral Bisphosphonate Therapy: Findings From a Real-World Data Analysis.

Abstract

Adherence to osteoporosis treatment remains poor despite available treatments and physician and patient education. This study aims to determine the effect of low adherence in real-world data. To examine the association between adherence with oral bisphosphonate therapy and fracture risk as well as health care resource utilization. Women included in this retrospective analysis were 55 years or older and had started oral bisphosphonate therapy between 2005 and 2011 in a large not-for-profit health care center in Israel. Adherence to therapy was measured by the medication possession ratio (MPR) during the first year from therapy initiation. Patients with MPR lower than 70% were considered nonadherent. Study outcomes were osteoporotic fracture events and health care utilization (including physician visits and hospitalizations) during the second year from therapy initiation. Among the 17 770 women included in the analysis (mean age = 66.5 years; SD = ±8.3 years), 48.9% were nonadherent to therapy during the first year of treatment. Osteoporotic fracture risks during the second year among adherent and nonadherent patients were 2.1% and 2.5%, respectively (P = 0.1). When analysis was limited to patients 75 years or older, nonadherence with bisphosphonates was associated with an adjusted odds ratio of 1.49 (95% CI = 1.08-2.04) for osteoporotic fractures compared with adherent patients. Nonadherent patients had 13.4% higher medical costs than their adherent counterparts among patients 75 years and older (P = 0.002). In patients 75 years and older, nonadherence with oral bisphosphonates can be associated with significantly greater short-term risk of osteoporotic fractures and higher utilization of health care services.