Quality assessment of randomized controlled trials of compound glycyrrhizin for urticaria

OBJECTIVE To investigate the quality of randomized controlled trials(RCTs) involving compound glycyrrhizin for urticaria,and try to improve therapeutic RCTs' quality by recognizing the current situation of Chinese RCTs.METHODS RCTs published from January 2000 to December 2011 about compound glycyrrhizin for urticaria were retrieved from PubMed,Medline,Cochrane Library,The National Research Rigester,CBM,VIP,CNKI databases.The methodological quality was evaluated according to the methods recommended by the revised Jadad scale,CONSORT checklist,recommendation by the Cochrane Collaboration,and GRADE system.RESULTS A total of 124 RCTs were included,the assessment of revised Jadad scale showed: there was no RCTs scored 5～7,3(2.4%) scored 4,1(0.8%) scored 3,105(84.7%) scored 2,11(8.9%) scored 1,and the other 4(3.2%) scored zero.According to the standard of CONSORT,only 7(5.6%) described the random method,no literatures explained how to execute randomization and use placebo control;1(0.8%) RCT performed single blind,1(0.8%) RCT performed double blind;2(1.6%) RCTs calculated statistic values;5(4.0%) RCTs reported follow-up;no RCTs reported equivalent results or negative results;79(63.7%) RCTs reported adverse events;no RCTs conducted sample size estimation,intention-to-treat analyses and stratified analyses.As to the risk of bias table:3(2.4%) RCTs described the random method correctly;4(3.2%) RCTs showed wrong random method;and the other 114(91.9%) RCTs were unclear of the random method,only 1(0.8%) RCT performed double blind,all RCTs were unclear of allocation concealment;all had incomplete outcome data and free of selective reporting and other bias.According to GRADE system: all RCTs were assessed as very low.Also,there was no RCT showed clinical trial registration,ethics approval and the informed consent.CONCLUSION The quality of RCTs about compound glycyrrhizin for urticaria is low in methodological aspects,which influenced on the authority of effect.Thus there is a huge room for improvement on adequate sequence generation,allocation concealment,blinding,sample size estimation,follow-up and adverse events,etc.And revised Jadad scale,CONSORT checklist,recommendation by the Cochrane Collaboration,and GRADE system can be used for quality assessment and study design.