OBJECTIVES: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) - The Cochrane Library, Issue 10, 2013, MEDLINE (1966 to 2013), EMBASE (1980 to 2013), LILACS (1982 to 2013), and ACP Journal Club, and we handsearched reference lists of published articles. We also searched the World Health Organization International Clinical Trials Platform ( http://www.who.int/trialsearch/Default.aspx) to identify ongoing trials and screened reference lists of retrieved review articles and trials to identify potentially relevant studies. All searches were up to date as of March 2013.
Pharmaceutical companies and authors of published articles were contacted. We searched the websites of the regulatory agencies using the keyword '
diacerein' in November 2013. No language restrictions were applied.
SELECTION CRITERIA: Data abstraction and quality assessment were performed by two independent investigators, and their results were compared. The Cochrane risk of bias tool was used. The quality of evidence obtained was assessed using the GRADE approach.
MAIN RESULTS: We identified three new trials (141 participants), and this updated review now includes 10 trials, totalling 2,210 participants. The most frequent risk of bias was incomplete outcome data, identified in approximately 80% of the studies. Allocation concealment and random sequence generation were unclear in 90% and 40% of the studies, respectively, because of poor reporting.Low-quality evidence from six trials (1,283 participants) indicates that
diacerein has a small beneficial effect on overall
pain (measured on a 100 mm visual analogue scale) at three to 36 months (mean difference (MD) -8.65, 95% confidence interval (CI) -15.62 to -1.68), which is equivalent to a 9%
pain reduction in the
diacerein group (95% CI -16% to -2%) compared with the placebo group. This benefit may not be clinically significant.No statistically significant differences in physical function (4 studies, 1006 participants) were noted between the
diacerein and placebo groups (Lequesne impairment index, 0 to 24 points) (MD -0.29, 95% CI -0.87 to 0.28).Low-quality evidence from two trials (616 participants) on slowing of joint space narrowing (a decrease greater than 0.50 mm) in the knee or hip favoured
diacerein over placebo (risk ratio (RR) 0.85, 95% CI 0.72 to 0.99), with an absolute risk difference of -6% (95% CI -15% to 2%) and a number needed to treat for an additional beneficial outcome (NNTB) of 14 (95% CI 8 to 203). Analysis of the knee joint alone (1 study, 170 participants) did not reach statistical significance (RR 0.94, 95% CI 0.51 to 1.74).None of the trials of
diacerein versus placebo measured quality of life. According to one trial (161 participants), which compared
diacerein versus non-steroidal anti-inflammatory drugs (
NSAIDs), the quality of life of participants in the two groups (as assessed by the Short Form (SF)-36 health survey questionnaire (0 to 800 sum score)) did not differ significantly (MD -40.70, 95% CI -85.20 to 3.80).Low-quality evidence from seven trials showed significantly more adverse events in the
diacerein group compared with the placebo group after two to 36 months, mainly diarrhoea (RR 3.52, 95% CI 2.42 to 5.11), with an absolute risk increase of 24% (95% CI 12% to 35%), and a number needed to treat for an additional harmful outcome (NNTH) of 4 (95% CI 3 to 7).No statistically significant differences in participant withdrawal due to adverse events were seen at two to 36 months for
diacerein compared with placebo (RR 1.29, 95% CI 0.83 to 2.01).A search of regulatory websites found a recommendation from the European Medicines Agency (EMA) Pharmacovigilance Risk Assessment Committee (PRAC) that the marketing authorization of
diacerein should be suspended across Europe because of harms (particularly the risk of severe diarrhoea and potentially harmful effects on the liver) outweighing benefits. However, this guidance is not final as the PRAC recommendation will be re-examined.
AUTHORS' CONCLUSIONS: In this update, the strength of evidence for effectiveness outcomes was low to moderate. We confirmed that symptomatic benefit provided by
diacerein in terms of
pain reduction is minimal. The small benefit derived in terms of joint space narrowing is of questionable clinical relevance and was observed only for OA of the hip. With respect to adverse effects of
diacerein, diarrhoea was most frequent. Given the recent guidance issued by the EMA recommending
suspension of
diacerein in Europe, the EMA website should be consulted for further recommendations regarding the use of
diacerein.