Thirteen studies were included in the review (n=1,790 patients; range 42 to 473), including three RCTs (n=292 patients) and ten observational studies. Study quality of the RCTs was judged to be acceptable; study quality of the observational studies was judged to be slightly worse than the RCTs, with unclear reporting. Hernia size appeared to be a confounder. Mean follow-up duration (where reported) ranged from 20 months to 40 months; median follow-up duration (where reported) ranged from 25 months to 54 months.
There were statistically significant pooled effects favouring mesh over suture for hernia recurrence: for RCTs only, the odds ratio was 0.09 (95% CI 0.02 to 0.39; three RCTs; I2=0%; fixed-effect); for cohort studies only, the odds ratio was 0.40 (95% CI 0.21 to 0.75; ten studies; I2=3%; fixed-effect). There was no statistically significant difference between groups for wound complications. Statistical heterogeneity was substantial for wound complications, but not for hernia recurrence.
The jack-knife approach indicated that the statistical heterogeneity in wound complication outcomes was driven by one study. Removing this study from pooled results did not change either of the main outcomes.
Funnel plots did not suggest publication bias.