Two authors independently screened search results for relevant studies, extracted data into a standardised form and assessed the risk of bias of included studies. We pooled data if deemed to be sufficiently clinically homogeneous. We assessed the quality of the body of evidence for each outcome using the GRADE approach.
MAIN RESULTS: Two RCTs (124 participants) were included in this updated review, including one new RCT. We considered one trial to be at low risk of bias, while we considered the newly included trial to be at unclear risk of bias. Both trials included a placebo and a high-dose
colchicine arm, although the
colchicine regimens varied. In one trial 0.5 mg
colchicine was given every two hours until there was either complete relief of symptoms or toxicity and the total doses were not specified. In the other trial a total of 4.8 mg
colchicine was given over six hours. The newly identified trial also included a low-dose
colchicine arm (total 1.8 mg over one hour).Based upon pooled data from two trials (124 participants), there is low-quality evidence that a greater proportion of people receiving high-dose
colchicine experience a 50% or greater decrease in
pain from baseline up to 32 to 36 hours compared with placebo (35/74 in the high-dose
colchicine group versus 12/50 in the placebo group (risk ratio (RR) 2.16, 95% confidence interval (CI) 1.28 to 3.65), with a number needed to treat to benefit (NNTB) of 4 (95% CI 3 to 12). However, the total number of adverse events (diarrhoea,
vomiting or
nausea) is greater in those who receive high-dose
colchicine versus placebo (62/74 in the high-dose
colchicine group versus 11/50 in the placebo group (RR 3.81, 95% CI 2.28 to 6.38), with a number needed to treat to harm (NNTH) of 2 (95% CI 2 to 5). Only one trial included reduction of
inflammation as part of a composite measure comprising
pain, tenderness, swelling and
erythema, each graded on a four-point scale (none 0 to severe 3) to derive a maximum score for any one joint of 12. They reported the proportion of people who achieved a 50% reduction in this composite score. Based upon one trial (43 participants), there was low-quality evidence that more people in the high-dose
colchicine group had a 50% or greater decrease in composite score from baseline up to 32 to 36 hours than people in the placebo group (11/22 in the high-dose
colchicine group versus 1/21 in the placebo group (RR 10.50, 95% CI 1.48 to 74.38) and 45% absolute difference).Based upon data from one trial (103 participants), there was low-quality evidence that low-dose
colchicine is more efficacious than placebo with respect to the proportion of people who achieve a 50% or greater decrease in
pain from baseline to 32 to 36 hours (low-dose
colchicine 31/74 versus placebo 5/29 (RR 2.43, 95% CI 1.05 to 5.64)), with a NNTB of 5 (95% CI 2 to 20). There are no additional harms in terms of adverse events (diarrhoea,
nausea or
vomiting) with low-dose
colchicine compared to placebo (19/74 and 6/29 respectively (RR 1.24, 95% CI 0.55 to 2.79)).Based upon data from one trial (126 participants), there is low-quality evidence that there are no additional benefits in terms of the proportion of people achieving 50% or greater decrease in
pain from baseline up to 32 to 36 hours with high-dose
colchicine compared to low-dose (19/52 and 31/74 respectively (RR 0.87, 95% CI 0.56 to 1.36). However, there were statistically significantly more adverse events in those who received high-dose
colchicine (40/52 versus 19/74 in the low-dose group (RR 3.00, 95% CI 1.98 to 4.54)), with a NNTH of 2 (95% CI 2 to 3).No trials reported function of the target joint, patient-reported global assessment of treatment success, health-related quality of life or withdrawals due to adverse events. We identified no studies comparing
colchicine to non-steroidal anti-inflammatory drugs (
NSAIDs) or other active treatments such as
glucocorticoids (by any route).
AUTHORS' CONCLUSIONS: Based upon only two published trials, there is low-quality evidence that low-dose
colchicine is likely to be an effective treatment for acute
gout. We downgraded the evidence because of a possible risk of selection and reporting biases and imprecision. Both high and low-dose
colchicine improve
pain when compared to placebo. While there is some uncertainty around the effect estimates, compared with placebo, high-dose but not low-dose
colchicine appears to result in a statistically significantly greater number of adverse events. Therefore low-dose
colchicine may be the preferred treatment option. There are no trials about the effect of
colchicine in populations with comorbidities or in comparison with other commonly used treatments, such as
NSAIDs and
glucocorticoids.