Meta-Analyses in Plastic Surgery: Can We Trust Their Results?

BACKGROUND: Meta-analyses are common in the plastic surgery literature, but studies concerning their quality are lacking. The authors assessed the overall quality of meta-analyses in plastic surgery, and attempted to identify variables associated with scientific quality.

METHODS: A systematic review of meta-analyses published in seven plastic surgery journals between 2007 and 2017 was undertaken using a computerized search. Publication descriptors and methodological and statistical details were extracted. Articles were assessed using the AMSTAR (A Measurement Tool to Assess Systematic Reviews) and AMSTAR 2 instruments.

RESULTS: Seventy-four studies were included. The number of meta-analyses per year increased. Most meta-analyses assessed a single intervention (59.5 percent), and pooled a mean of 20.9 studies (range: 2-134), including a mean of 2,463 patients (range: 44-14,884). Most meta-analyses were published in Plastic & Reconstructive Surgery (44.6 percent), and included mid-level evidence (II to IV) primary studies. Only 16.2 percent of meta-analyses included randomized controlled trials. Meta-analyses generally reported positive (81.1 percent) and significant results (77.0 percent). Median AMSTAR score was 7/11 (interquartile range=5-8). AMSTAR scores correlated with year of publication (p=0.04, R=0.24). Higher AMSTAR scores correlated with more recent meta-analyses that provided a rationale for statistical pooling, and appropriately managed methodological heterogeneity (r=0.66, p<0.01).

CONCLUSIONS: Despite an increase in the number and quality of meta-analyses, these studies are at high risk of bias due to the low level of evidence of included primary studies and heterogeneity within and between primary studies. Plastic surgeons should be aware of the pitfalls of conducting and interpreting meta-analyses.