Diagnostic Accuracy of Self-Reported Questionnaires for Detecting Periodontitis Across Multiple Cultures and Geographic Locations: A Systematic Review and Meta-Analysis.

To evaluate self-reported questionnaires' intrinsic validity and diagnostic accuracy for detecting periodontitis across diverse cultural and geographic contexts. Electronic searches were conducted in PubMed, Embase and the Cochrane Library until 4 March 2025. Studies included those using the Centers for Disease Control and Prevention and the American Academy of Periodontology (CDC/AAP) criteria or the 2017 World Workshop classifications as reference standards and reporting the diagnostic accuracy of self-reported questionnaire items. The validity of the eight-item questionnaire developed by the CDC/AAP was assessed by analysing the proportion of answers, and bias was evaluated using the QUADAS-2 tool. Owing to the limited number of studies using the 2017 World Workshop classifications, the quantitative synthesis was restricted to those using the CDC/AAP criteria. Sensitivity, specificity, diagnostic odds ratio (DOR) and 95% confidence intervals (CIs) were calculated for total periodontitis (including mild, moderate and severe cases), moderate-to-severe periodontitis and severe periodontitis. Totally, 23 studies (from 22 articles) were included in the systematic review, with 16 studies (from 15 articles) eligible for meta-analysis. The 'Don't know/Refused' option across the eight items of the CDC/AAP questionnaire ranged from 0% to 46.1%, indicating variable comprehension of certain items. Pooled sensitivity and specificity across the questionnaire items ranged from 17% to 82% and from 23% to 97%, respectively. DOR varied from 0.75 (95% CI: 0.54-1.03) to 8.01 (95% CI: 2.33-27.45). Significant heterogeneity was observed for most questions. Self-reported questionnaires show potential for monitoring periodontitis but face issues with sensitivity and cross-cultural validity. Future research should focus on culturally adaptive designs and standardised validation protocols to enhance diagnostic accuracy and improve their effectiveness in global periodontal health screening.