Objective To assess whether English-speaking reviewers can identify foreign-language articles that are eligible for a systematic review of all treatments for fibromyalgia.

Methods Systematic review of AMED, CINAHL, EMBASE, MEDLINE, HealthSTAR, PsycINFO, Papers First, Proceedings First and CENTRAL, from inception of each database to April, 2011, to identify all randomised controlled trials exploring any form of therapy for fibromyalgia. All non-English language articles were identified and screened for eligibility by native-language reviewers. English-speaking reviewers screened all non-English language, guided by 10 questions, in order to identify those that were eligible for review.

Results Of 15,466 potentially eligible studies we retrieved 763 in full text, of which 133 were published in 19 non-English languages; 431 studies proved eligible of which 53 were published in languages other than English. Agreement between English and native-language reviewers for assessment of eligibility of the 133 foreign language articles was 89% and the chance-corrected agreement was substantial (kappa = 0.77). Use of a simple 4-step rule (excluding languages with only one or two articles, reviewing titles and abstracts for clear indications of eligibility, noting the lack of a clearly reported statistical analysis unless the word ‘random’ appears, and noting features of systematic review) preserved the highest proportion of eligible articles (96%) with the fewest number of foreign-language reviewer teams needed (n = 9).

Conclusions We identified strategies that English-speaking reviewers can implement to ameliorate the burden associated with including eligible non-English language studies in systematic reviews.