Factors associated with acute gout attacks in normouricaemic gout patients receiving allopurinol: a retrospective study

Abstract

Objective: To identify factors associated with acute gout attacks in normouricaemic gout patients receiving allopurinol.

Methods: We reviewed the medical records of 860 patients with chronic gout who were treated with allopurinol at a single tertiary hospital between 2003 and 2009. Of these, 135 patients had serum urate concentrations ≤ 360 μmol/L (6 mg/dL). Patients whose serum urate concentrations exceeded 360 μmol/L (6 mg/dL) at least once during follow-up were excluded. Patients who experienced at least one acute attack during follow-up, despite normouricaemia [≤ 360 μmol/L (6 mg/dL)], were classified as the Attack group (n = 51). The others were classified as the Non-attack group (n = 84).

Results: The gout disease duration was significantly longer in the Attack group than in the Non-attack group (p = 0.036). The presence of tophi and multiple joint involvement were associated with acute attacks in normouricaemic gout patients. Multivariate analysis showed that both the presence of tophi [odds ratio (OR) 4.16, 95% confidence interval (CI) 1.41-12.23, p = 0.010] and the number of involved joints (OR 1.51, 95% CI 1.05-2.17, p = 0.028) were independently associated with acute attacks in normouricaemic gout patients receiving allopurinol.

Conclusion: The presence of tophi and multiple joint involvement were associated with acute attacks in normouricaemic gout patients receiving allopurinol.