Persistence to osteoporosis drugs following an incident osteoporotic fracture: The prefrac study

Introduction: No studies have been conducted that determine long-term persistence to osteoporosis drugs prescribed specifically for the secondary prevention of fractures. Persistence to these drugs is important in this patient group because of the high risk of subsequent fracture. Material and Methods: A population-based cohort study was conducted using data from the Dutch PHARMO Database Network (January 2002 to December 2011). We identified all patients≥50 years who initiated osteoporosis therapy (bisphosphonates, strontiumranelate, raloxifene, denosumab) within 1 year following their first fracture (hip, spine, forearm, upper arm). Kaplan-Meier life-table analysis was used to calculate the cumulative incidence probability (%) for persistence to osteoporosis drugs. Discontinuation of osteoporosis drugs was defined as a treatment gap of >90 days. Timedependent Cox regression was used to estimate fully adjusted hazard ratios (aHRs) with 95 % confidence intervals (95 % CIs) for determinants of discontinuation of osteoporosis drugs. Covariates included age, sex, comorbidities including the type of fracture, and drug use 6 months prior. Discussion: A total of 976 patients initiated osteoporosis drugs within 1 year after their first fracture. Within 1 year following initiation 74 % (95 % C I: 67-76 %) persisted with treatment, which had dropped to 39 % (95 % C I: 35-44 %) after 5 years. Determinants for discontinuation of osteoporosis therapy included age≥80 years (aHR 1.9; 95 % C I: 1.4-2.5) (reference: patients aged 60-69 years) and recent use of proton pump inhibitors [PPIs] or H2-receptor antagonists without use of non-steroidal anti-inflammatory drugs [NSAIDs] (aHR 1.5; 95 % C I: 1.2-1.9). Concomitant use of PPIs or H2-receptor antagonists and NSAIDs did not elevate the risk of discontinuation with osteoporosis drugs (aHR 0.9; 95 % CI: 0.7-1.3). Conclusions: This study shows a major treatment failure for the secondary prevention of osteoporotic fractures; more than half of all patients had discontinued treatment within the recommended treatment duration of 5 years. This was even worse in the elderly and discontinuation may be related to the occurrence of gastro-intestinal side-effects.