Pseudogout Study: Colchicine vs. Prednisone

Pseudogout or "false gout" is a form of arthritis that results from deposits of calcium pyrophosphate crystals. It is commonly known to affect the knees and wrists. Not much is known regarding the guidance and evidence; management of this disease relies on expert opinion.

Prof. Tristan Pascart and team aimed to compare the safety and short-term equivalence of low-dose colchicine with oral prednisone in older patients with acute calcium pyrophosphate crystal arthritis. An open randomized trial COLCHICORT in The Lancet Rheumatology found that low doses of colchicine and prednisone exhibit the same level of efficacy for the treatment of acute calcium pyrophosphate crystal arthritis; however, they showed differences in safety profiles in the older population.

Researchers conducted an open-label, multicentre, randomised trial (COLCHICORT) at six hospitals in Paris and northern France. They enrolled patients who were admitted to hospital, who were 65 years or older, and who presented with acute calcium pyrophosphate crystal arthritis with a symptom duration of less than 36 hours. Diagnosis of calcium pyrophosphate crystal arthritis was made by the identification of calcium pyrophosphate crystals on synovial fluid analysis or typical clinical presentation.

Participants were randomly allocated (1:1), using a centralised electronic treatment group allocation module, to receive either colchicine 1.5 mg on day 1 and 1 mg on day 2 (i.e., the colchicine group) or oral prednisone 30 mg on days 1 and 2 (i.e., the prednisone group). The primary outcome was change in joint pain at 24 hours. Equivalence was determined whether the 95% CI of the between-group difference at 24 hours was within the –13 mm to +13 mm margin in the per-protocol analysis.

Key Findings of the Study

• Out of 111 patients who were admitted to hospital, 57 (51%) were assigned to the colchicine group and 54 (49%) to the prednisone group.
• Acute calcium pyrophosphate crystal arthritis affected mainly the knee in 46 (48%) of 95 participants, the wrist in 19 (20%), and the ankle in 12 (13%).
• Pain VAS at baseline was 68 mm (SD 17). At 24 hours, change in pain VAS was –36 mm (SD 32) in the colchicine group and –38 mm (SD 23) in the prednisone group.
• The between-group difference in change in pain VAS at 24 hours was –1 mm (95% CI –12 to 10), showing equivalence between the two drugs.
• In the colchicine group, 12 (22%) of 55 patients had diarrhoea, one (2%) had hypertension, and none had hyperglycaemia.
• In the prednisone group, three (6%) of 54 had diarrhoea, six (11%) had hypertension, and three (6%) had hyperglycaemia.

Researchers concluded that “Colchicine and prednisone exhibit equivalent short-term efficacy for the treatment of acute calcium pyrophosphate crystal arthritis, with different safety profiles in the older population.”

Reference: Prof Tristan Pascart, MD PhD, Pierre Robinet, MD, Sébastien Ottaviani, MD, Rémi Leroy, MD; Evaluating the safety and short-term equivalence of colchicine versus prednisone in older patients with acute calcium pyrophosphate crystal arthritis (COLCHICORT): an open-label, multicentre, randomised trial, August 08, 2023; Lancet Rheumatology. DOI: https://doi.org/10.1016/S2665-9913(23)00165-0.