Background and objective: Disease history and clinical features can influence treatment response in patients with acute gout. The purpose of this pooled subgroup analysis was to assess the association of baseline disease and patient characteristics with response to treatment in acute gout using data from two identical studies.
Methods: Patients > or = 18 years of age with onset of acute gout within 48 h associated with moderate, severe, or extreme pain involving less than four joints were eligible for inclusion in the primary studies, and were randomized to etoricoxib 120 mg once daily (N = 178) or indomethacin 50 mg three times daily (N = 161). The primary and secondary efficacy endpoints were analyzed using an analysis of covariance model to detect potential differential treatment responses across several subgroups: joint involvement (mono-articular vs. oligo-articular), baseline pain severity (moderate vs. severe), concomitant allopurinol and/or colchicine use (users vs. nonusers), age (< 45, 45-55, and > 55 years), gender, and race (white or other).
Results: Overall, etoricoxib and indomethacin demonstrated comparable efficacy across all subgroups. Compared with patients with oligo-articular disease, those with mono-articular disease had significantly greater improvements in patient assessment of pain, patient global assessment of response to therapy (PGART), investigator global assessment of response to therapy (IGART), and study joint tenderness (p < 0.001 for all). Greater improvements were seen in patient assessment of pain (p < 0.001) and study joint tenderness (p < 0.05) for severe/extreme baseline pain compared with moderate baseline pain. Concomitant use of colchicine and/or allopurinol was associated with significantly worse IGART (p < 0.05).
Conclusions: This pooled subgroup analysis demonstrated significantly greater response of acute gout to either etoricoxib or indomethacin among those with monoarticular disease, severe/extreme baseline pain, and non-use of colchicine and/or allopurinol. These results should be interpreted in the context of a pooled subgroup analysis with a limited sample size, and with the understanding that associations identified in such analyses do not define causation. Despite limitations, the results provide insights into the types of patients more likely to respond better to anti-inflammatory medication, and reiterate the importance of earlier effective control of the disease.
Trial registration: ClinicalTrials.gov NCT00142558.