COMPLETENESS OF REPORTING OF TRIALS PUBLISHED IN LANGUAGES OTHER THANENGLISH - IMPLICATIONS FOR CONDUCT AND REPORTING OF SYSTEMATIC REVIEWS

Background Lately, the number of systematic reviews published has incr eased substantially. Many systematic reviews exclude trials published in languages other than English. However, there is little empirical ev idence to support this action. We looked for differences in the comple teness of reporting between trials published in other languages and th ose published in English, to see whether the exclusion of trials publi shed in other languages is justified. Methods We compared completeness of reporting, design characteristics, and analytical approaches of 13 3 randomised controlled trials (RCTs) published in English between 198 9 and 1994 and 96 published in French, German, Italian, or Spanish dur ing the same time. RCTs were identified by hand searching of journals (seven in English and six in the other languages). Findings We found n o significant differences between trials published in English and othe r-language trials for any single item in the completeness of reporting scale (randomisation, double-blinding, withdrawals), or for the overa ll score (percentage of maximum possible score 51.0% for trials in Eng lish, 46.2% for trials in other languages, 95% CI for difference -1.1 to 10.5). Other-language trials were more likely than English-language trials to have adult participants, to use two or more interventions, and to compare two or more active treatments without an untreated cont rol group. Trials in other languages were less likely to report a clea rly prespecified primary outcome or any rationale for sample size esti mation. Interpretation These results provide evidence for inclusion of all trial reports, irrespective of the language in which they are pub lished, in systematic reviews, Their inclusion is likely to increase p recision and may reduce systematic errors. We hope that our findings w ill prove useful to those developing guidelines and policies for the c onduct of reporting of systematic reviews.