RESUMO
Estimates of pes planus ("flatfoot") prevalence vary considerably across studies. Moreover, there is uncertainty over which factors are associated with the pes planus prevalence. We aimed to systematically review the prevalence and clinical factors associated with flatfoot among children and adults. We searched Web of Science, PubMed/MEDLINE, and Google Scholar databases reporting population-based flatfoot prevalence. Two reviewers independently extracted the data and assessed the qualities of the studies. Subgroup analysis was conducted to analyze the associated factors on flatfoot prevalence. Frequencies, odds ratios (OR), and 95% confidence intervals (CI) were performed using descriptive analysis and chi-square test accounting for heterogeneity. Any conflict in the data analysis was discussed by all the reviewers. Twelve studies including 2509 flatfoot cases were analyzed (overall prevalence 15.6%, n = 16,000). The subgroup analysis indicated that male gender (OR = 1.26, 95% CI: 1.15-1.37), age groups 3 to 5 years (OR = 2.02, 95% CI: 1.78-2.30) and 11 to 17 years (OR = 1.91, 95% CI: 1.64-2.22), Asian race (OR = 2.34, 95% CI: 2.10-2.60), and obesity (OR = 2.62, 95% CI: 2.06-3.32) were more associated with flatfoot (p < .001). Conversely, female gender (OR = 0.44, 95% CI: 0.40-0.48) and White race (OR = 0.52, 95% CI: 0.47-0.57) were less associated with flatfoot (p < .001). Our findings may be valuable for clinical/surgical settings, particularly, for those modifiable findings and targeted populations. However, we suggest that future studies estimating flatfoot should consider prospective/multicenter designs using a common screening methods in random samples populations.