Non-loading versus loading low-dose colchicine in acute crystal-associated arthritis: A double-blinded randomized controlled study.

INTRODUCTION: This study aimed to compare the efficacy of non-loading versus loading low-dose colchicine in patients with acute crystal-associated arthritis.

MATERIALS AND METHODS: All in-patients who were admitted to Chiang Mai University Hospital with non-arthritis disease and developed acute crystal-associated arthritis during admission (within 48 h after arthritis onset) were invited to join this study. The patients were randomized into two groups. Patients in Group I (non-loading group) and Group II (loading group) received colchicine at 1.2 and 2.4 mg in the first 24 h, respectively. The primary outcome was the patients' pain response at 24 h after treatment.

RESULTS: Of 80 patients, 49 were acute gouty arthritis, and 31 acute calcium pyrophosphate (CPP) arthritis. The mean [95% CI] pain score was no different between Groups I and II at the baseline level (6.46[5.72-7.19] vs. 6.654[5.85-7.44], p = .867) and at 24 h (3.13[2.43-3.82] vs. 3.18[2.42-3.93], p = .907). The proportion of patients with ≥50% pain reduction was not different (57.50% vs. 55.00%, p = .822). Sensitivity analysis among patients with a baseline pain score of ≥4 showed the same pattern of response. Mild diarrhea was common and comparable in both groups. Subgroup analysis according to renal function (eGFR < 60 vs. ≥60 mL/min/1.73 m2 ) or type of crystals (acute gouty arthritis vs. acute CPP arthritis) also showed the same pattern of response.

CONCLUSION: Non-loading low-dose colchicine was as effective as loading low-dose colchicine in patients with acute crystal-associated arthritis, regardless of renal function or type of crystals.