there has been only little research on randomised controlled trials (RCT) reported in languages other than English. Prompted by the efforts of the Cochrane Collaboration to identify all published controlled trials,3
we manually searched two leading Croatian medical journals, one publishing in Croatian and the other mainly in English. Both have been in Index Medicus
since 1960. Did Croatian journals publish RCTs and were those reports readily accessible on Medline?
Full-text search of the journals for the 6 years 1988—93, which included 2 war years (1991—92), revealed that the two journals published 23 RCTs (4·2% of all clinical reports). A further 38 controlled studies (6·9% of clinical reports) satisfied the criteria for quasi-RCTs, eligible for the Cochrane Controlled Trial Register.3
The number of RCTs did not change over the years, and was not much below the numbers reported in the same period for Austria,2
a country with a much stronger scientific output.4
Most of the trials compared two drugs of the same therapeutic class, and half the trials reported significant differences.
A Medline search using the first stage of an optimised search strategy for RCT retrieval,5
identified ten RCTs (table
), well below the usual two-thirds of RCTs identifiable in Medline journals.5
Croatian language could not be the reason, because the sensitivity and precision of the searches were similar for the journal publishing in English and the one publishing in Croatian (table
). All ten RCT reports retrieved by the Medline search had in their abstracts a clear statement about the study design, control intervention, sample size, and randomisation protocol. The other 13 required a careful reading of the full text to assess the type of study.
Results of Medline search*
for RCTs in two Croatian general medical journals between 1988 and 1993
We urge authors writing up RCTs and editors to pay great attention to the clarity of the presentation. A report on an RCT can be retrieved via Medline when it is clearly written, when it will be available for a systematic review or meta-analysis irrespective of language.