Language of publication restrictions in systematic reviews gave different results depending on whether the intervention was conventional or complementary

Ref ID 398
First Author B. Pham
Journal JOURNAL OF CLINICAL EPIDEMIOLOGY
Year Of Publishing 2005
URL https://www.jclinepi.com/article/S0895-4356(05)00059-4/fulltext
Keywords • Complementary & Alternative
Problem(s) • Language restriction
Article Type Empirical
Article Subtype Small analytical study
First Author Country Canada
Aim To assess the extent to which including trials reported in languages other than English influences the results of systematic reviews for both conventional medicine and complementary and alternative medicine interventions.
Level of Investigation Descriptive
Summary of Findings For conventional medicine interventions, language-restricted systematic reviews, compared with language-inclusive ones, did not introduce biased results, in terms of estimates of intervention effectiveness. For complimentary and alternative medicines interventions, however, language-restricted systematic reviews resulted in a 63% smaller protective effect estimate than language inclusive reviews
Number of systematic reviews included 42
Number of eligible systematic reviews assessed 42
Treatment impacted Yes
Treatment impacted description
Interpretation impacted Yes
Interpretation impacted description For complimentary and alternative medicine, inclusion of trials from languages other than English had a significant impact on the treatment effect.