Evaluation of meta-analyses in the otolaryngological literature

To evaluate the quality of meta-analyses written on otolaryngological topics and define areas that can be improved upon in future studies.

MEDLINE (PubMed) and EMBASE databases were searched. The Cochrane database of systematic reviews was excluded, because these meta-analyses have already been critically evaluated and found to be of high quality.

A systematic review of otolaryngological meta-analyses published between 1997 and 2006 (10 years) was performed in duplicate and independently by two authors. The search included 16 common otolaryngological terms. Inclusion criteria were meta-analytic methodology, otolaryngological topic, and at least one author from a department of otolaryngology. Fifty-one articles fulfilled eligibility criteria. In duplicate and independently, two reviewers assessed the quality of eligible meta-analyses using a validated 10-item index called the Overview Quality Assessment Questionnaire. Using the methods of Spearman, correlation coefficients are reported for associations examined between covariates and the Overall Score Quality.

The majority of studies had methodologic flaws (mean score 3.9, scale of 1-7). Variables predicting higher-quality meta-analyses were publication in journals with higher impact factors (P = 0.0007) and authors who previously published meta-analyses (P = 0.0001). Using and reporting about a validity assessment tool needs to be improved upon in future studies.

The quality of meta-analyses on otolaryngological topics is moderate. Future meta-analyses can be improved upon by following evidence-based guidelines for the reporting of meta-analyses, which include the use of a validity assessment tool, and consulting with an author familiar with meta-analysis methodology.