Hidden effectiveness? Results of hand-searching Italian language journals for occupational health interventions.

Objective: To compare the yield of hand-searching with optimised electronic search strategies in retrieving occupational health (OH) intervention studies published in a language other than English.

Methods: The authors systematically hand-searched and screened reports of OH intervention studies published in Italian in peer-reviewed scientific journals between 1990 and 2008. The authors evaluated how many of them met the Cochrane Occupational Safety and Health Review Groups (OSHRG) definition of being an OH intervention study and how many potentially relevant studies retrieved by hand-searching would not be found by PubMed alone using the OSHRG's most specific and most sensitive search strings.

Results: Hand-searching retrieved 25 articles (reporting 27 studies), including nine not indexed in MEDLINE. Most studies (81%, 22/27) had a before-after design and only one was a randomised trial. The OSHRG's most sensitive search string retrieved all 16 articles published in the Italian language journals that were indexed in MEDLINE, while the most specific search strategy retrieved nine articles (56%, 9/16). The most specific search string showed a lower 'number needed to read' value than the most sensitive one (60 vs 132).

Conclusions: These findings suggest that a sensitive electronic search strategy may be able to find most of the OH interventions published in languages other than English that are indexed in MEDLINE. Hand-searching of important national journals not indexed in MEDLINE should be considered when conducting particularly in-depth research.