Gout and allopurinol adherence in newly diagnosed patients and the risk of fractures: a nationwide cohort study.

INTRODUCTION /

OBJECTIVES

The association between gout and fractures remains controversial due to the competing effects of uric acid's antioxidant properties and gout-induced chronic inflammation. Our study aimed to evaluate the risk of fractures in newly diagnosed gout patients and to analyze the impact of Allopurinol medication adherence on this risk.

METHODS

This nationwide cohort study utilized the National Health Insurance Service-National Health Screening Cohort (NHIS-HEALS) database (2002-2019). We identified 4,107 patients newly diagnosed with gout who remained on continuous allopurinol therapy during the 24-month medication assessment period and matched them 1:3 with 12,321 non-gout controls using propensity score matching. Allopurinol adherence was assessed via the Medication Possession Ratio (MPR) over a 24-month period and categorized into three groups: MPR < 0.3, 0.3 ≤ MPR < 0.8, and MPR ≥ 0.8. Multivariable Cox proportional hazards regression was used to calculate adjusted hazard ratios (aHR) and 95% confidence intervals (CI) for fractures (vertebral, hip, and distal radius).

RESULTS

Gout patients demonstrated a significantly higher risk of overall fractures compared to the non-gout group (aHR 5.52; 95% CI 4.19-7.26). A significant inverse linear relationship was observed between allopurinol adherence and fracture risk (P for trend < .001). The risk was highest in the low-adherence group (MPR < 0.3; aHR 5.91; 95% CI 4.40-7.93) and relatively lower in the high-adherence group (MPR ≥ 0.8; aHR 4.77; 95% CI 2.94-7.72). Consistent trends were observed for vertebral (aHR 5.68) and hip (aHR 4.22) fractures. These associations remained consistent across all subgroups, including age, sex, and comorbidities.

CONCLUSION

Newly diagnosed gout is associated with a substantially increased risk of fractures. Higher adherence to Allopurinol therapy is correlated with a significant reduction in this risk, suggesting that consistent urate-lowering therapy may mitigate gout-related bone fragility. Key Points • Newly diagnosed gout patients have a significantly higher risk of major osteoporotic fractures compared to the non-gout population. • A significant inverse linear relationship exists between Allopurinol adherence and fracture risk, with the highest adherence group (MPR ≥ 0.8) showing a relatively lower risk. • Consistent urate-lowering therapy (ULT) may mitigate bone fragility in gout patients by reducing systemic inflammatory burden caused by urate crystal deposition.