Abstract
OBJECTIVE: To appraise multiple systematic reviews on the same clinical topic, focusing on predictors and correlates of quality of reporting of meta-analysis (QUOROM) scores. DESIGN: Case study. SETTING: Reviews providing at least individual quantitative estimates on role of acetylcysteine in the prevention of contrast associated nephropathy. DATA SOURCES: PubMed, the database of abstracts of reviews of effects, and the Cochrane database of systematic reviews (updated March 2005). MAIN OUTCOME MEASURES: Funding, compliance with the QUOROM checklist, scores on the Oxman and Guyatt quality index, and authors' recommendations. RESULTS: 10 systematic reviews, published August 2003 to March 2005, were included. Nine pooled events despite heterogeneity and five recommended routine use of acetylcysteine, whereas the remaining studies called for further research. Compliance with the 18 items on the QUOROM checklist was relatively high (median 16, range 11 to 17), although shorter manuscripts had significantly lower scores (R = 0.73; P = 0.016). Reviewers who reported previous not for profit funding were more likely to score higher on the Oxman and Guyatt quality index. No association was found between QUOROM and Oxman and Guyatt scores (R = -0.06; P = 0.86), mainly because of greater emphasis of the Oxman and Guyatt scores on the appraisal of bias in selection and validity assessment (inadequate in five reviews). CONCLUSIONS: Multiple systematic reviews on the same clinical topic varied in quality of reporting and recommendations. Longer manuscripts and previous not for profit funding were associated with higher quality.