Background: randomized controlled trials (RCTs) provide the most reliable evidence about the efficacy of healthcare interventions when they are properly carried out. They are the best methodological design to prove causality when testing a research hypothesis, and the essential input to conduct systematic reviews (SR). Cochrane recommends complementing electronic strategies with a systematic handsearch (HS), in order to increase sensitivity in the retrieval of RCTs from most sources.
Objectives: to identify, describe and appraise RCTs retrieved from otorhinolaryngology journals published in Spanish until April 2018.
Methods: we first identified all Otorhinolaryngology journals in the Spanish language that publish original research. Six trained review authors then handsearched RCTs following Cochrane guidelines. We extracted the main demographic and methodological characteristics for each RCT, and appraised risk of bias using the RoB 2 tool. We recorded funding sources, conflicts of interest and adherence to CONSORT. We submitted the complete list of retrieved RCTs to CENTRAL.
Preliminary results: we identified 28 eligible otorhinolaryngology journals in Spanish, one of which was indexed in MEDLINE (Acta Otorrinolaringológica Española). We screened a total of 3955 references, of which 35 (8.8%) were RCTs. These RCTs included 2299 participants; 32 our of 35 (91%) RCTs reported the age of participants, whereas all RCTs reported their gender. The most investigated topics were tonsillectomy (5/35, 14%), tympanic membrane perforation (4/35, 11%) and sensorineural hearing loss (4/35, 11%). Regarding risk of bias, 29 of 35 (88%) RCTs were high risk of bias, mainly due to selective outcome reporting. While 9% (3/35) of the RCTs mentioned funding sources, 31% (11/35) reported the commercial brand and name of the manufacturer when describing assessed interventions. 30 of 35 (86%) did not report any information on conflicts of interest; the remaining five (14%) declared no conflict of interest to disclose. No RCT declared adhering to CONSORT. We compared HS versus electronic searching for Acta Otorrinolaringológica Española: HS identified all of the 12 RCTs retrieved via electronic searching, whereas electronic searching retrieved 10 of the 12 RCTs retrieved via HS.
Conclusions: otorhinolaryngology journals in Spanish publish a low number of RCTs. Most of the identified RCTs had a high risk of bias and poor reporting of methods and results. Lack of disclosure of conflcts of interest and funding further hinders full assessment of the quality of the identified RCTs. There is a need to adhere to CONSORT and other international guidance when designing and reporting otorhinolaryngology RCTs in Spain and Latin America.
Patient or healthcare consumer involvement: we did not involve any patients or consumers in this project. However, proper RCT reporting and retrieval is crucial to acknowledge patient input during RCT development.