At least ninety days of follow-up are required to adequately detect wound outcomes after open incisional hernia repair.

A considerable proportion of SSIs occurred beyond 30 days, but 90-day follow-up detected 92% of SSIs. Follow-up to 90 days captured only 83% of SSO-related readmissions. These results have implications for the design of trials evaluating wound complication after open IHR, as early endpoints may miss clinically relevant outcomes and underestimate the number needed to treat. Where possible, we recommend a minimum follow-up of 90 days to estimate wound complications following open IHR.