Comparative adherence to weekly oral and quarterly intravenous bisphosphonates among patients with limited heath literacy who sustained distal radius fractures

Individuals with limited health literacy (HL) are less likely to obtain preventive care. We designed a study to compare adherence to weekly oral and quarterly intravenous bisphosphonates among patients with low HL. The study enrolled a total of 432 female patients who presented with a distal radius fracture caused by low-energy trauma. Participant HL was measured using the Newest Vital Sign tool, and patients were randomized to weekly oral or quarterly intravenous bisphosphonate groups. Subjects in the intravenous bisphosphonate group received intravenous injections of 3 mg ibandronate every 3 months, and those in the oral bisphosphonate group self-administered 70 mg alendronate orally once each week for 12 months. The adherence to weekly oral or quarterly intravenous bisphosphonates was analyzed by HL level. The rate of adherence to quarterly intravenous bisphosphonates was significantly higher than that for weekly oral bisphosphonates in patients with inadequate HL (73 vs. 46%, p = 0.001), whereas no significant differences were observed between HL groups in adherence to intravenous bisphosphonate. Conversely, the rate of adherence to orally administered bisphosphonates was significantly lower in patients with inadequate HL than in those with appropriate HL (46 vs. 65%, p = 0.005). After controlling for confounding variables, inadequate HL, the presence of comorbidities, and weekly oral bisphosphonates were associated with a higher likelihood of nonadherence to osteoporosis treatment. Thus patients with limited health literacy can achieve rates of adherence to quarterly intravenous bisphosphonates, as opposed to weekly oral bisphosphonates, similar to rates among patients with appropriate literacy.