The review question and supporting inclusion criteria were clearly defined. The literature search was limited to two electronic databases, but attempts were made to locate unpublished data for trials included in the review. There was no evidence of publication bias. It was unclear whether any language restrictions were in place during the search, so it was unclear whether language bias was introduced. The authors undertook the data extraction in duplicate, but as it was unclear whether this was true for study selection, reviewer error and bias could not be ruled out.
The authors did not appear to have assessed validity, which meant that the quality of the included trials was unclear and that the reliability of the subsequent conclusions was also unclear. A large data set was included. Appropriate methods were used to pool the results and assess for statistical heterogeneity. The authors did acknowledge certain limitations with the included trials, such as differences in population characteristics and treatment methodology, and suggested that the findings should be interpreted with caution. The authors also acknowledged certain limitations with performing further statistical analyses due to insufficient data.
There was potential for bias in the review, but the authors' conclusions appear to reflect the evidence, which included a large sample population, and they acknowledged certain limitations with the included trials and statistical analyses.
Some of the authors disclosed financial links with various companies that market or manufacture lipid-lowering agents.