Prevalence of anal fistulas: a systematic review and meta-analysis.

Anal fistula refers to a clinical condition with local pain and inflammation associated with purulent discharge that affects the quality of life. Due to the lack of studies, the presence of bias, and high heterogeneity in the studies, the present systematic review is the first to be performed on the population-based database in this field. The present systematic review and meta-analysis was performed according to MOOSE guidelines. After systematic searching in electronic databases, only four articles met the inclusion criteria. After preparing a checklist and extracting data from the relevant articles, a meta-analysis was performed. All studies on the prevalence of anal fistula are related to Europe, and so far, no study has been conducted on other continents. The overall prevalence of anal fistula in European countries was 18.37 (95% CI: 18.20-18.55%) per 100,000 individuals, and the highest prevalence was reported for Italy (23.20 (95% CI: 22.82 to 23.59) per 100,000 people). From the present population-based (224,097,362) study results, it can be concluded that there is a prominent knowledge gap in this context. Because all the studies included in the current study relate only to Europe, the need for further research in this field in other countries is inevitably sensible.