Prevalence of Medication Nonadherence among Osteoporosis Patients: A Cross-sectional Study in Tabuk, Saudi Arabia

Osteoporosis is a chronic skeletal disorder characterized by reduced bone mass and deterioration of bone microstructural integrity, increasing fracture risk and morbidity worldwide. Despite the widespread use of effective antiosteoporotic therapies, adherence remains suboptimal worldwide, including in Saudi Arabia. Identifying factors associated with nonadherence is vital for informing effective interventions.

This study aimed to assess the prevalence of osteoporosis medication nonadherence and examine predictors of nonadherence, among adult patients in Tabuk, Saudi Arabia.

A cross-sectional study was conducted among 137 adults with osteoporosis receiving antiosteoporotic treatment at a tertiary care center in Tabuk, Saudi Arabia. Data on demographic characteristics, comorbidities, concurrent medications, fragility fracture history, medication type (oral vs. injectable), and dosing regimen were collected. Adherence was assessed using the validated 8-item Morisky Medication Adherence Scale through structured patient interviews and verified with medical records.

The prevalence of medication nonadherence was 29.9% (95% confidence interval (CI): 22.5%-38.2%). The area under the curve of the combined risk model was 0.704 (95% CI: 0.454-0.921). The model stratified patients into three risk categories: high (2.2%, 0% adherence), moderate (35.8%, 61.2% adherence), and low (62.0%, 77.6% adherence). At the optimal cutoff, sensitivity was 73.7% and specificity 75.0%. A clinical nomogram was developed for bedside risk assessment.

Nearly one-third of osteoporosis patients was nonadherent. Although no individual factors independently predicted nonadherence, the model showed good discriminability and provides a practical tool for targeted adherence support. Multicenter validation is needed before wider use.