Prevalence of diabetes mellitus in people clinically diagnosed with periodontitis: A systematic review and meta-analysis of epidemiologic studies.

OBJECTIVES: Diabetes mellitus and periodontitis are complex chronic diseases with an established bidirectional relationship. This systematic review evaluated in subjects with professionally diagnosed periodontitis the prevalence and odds of having diabetes. METHODS: The MEDLINE-PubMed, CENTRAL and EMBASE databases were searched. Prevalence of diabetes mellitus among subjects with periodontitis was extracted or if possible calculated. RESULTS: From the 803 titles and abstracts that came out of the search, 27 papers met the initial criteria. Prevalence of diabetes was 13.1% among subjects with periodontitis and 9.6% among subjects without periodontitis. Based on subanalysis, for subjects with periodontitis, the prevalence of diabetes was 6.2% when diabetes was self-reported, compared to 17.3% when diabetes was clinically assessed. The highest prevalence of diabetes among subjects with periodontitis was observed in studies originating from Asian countries (17.2%, n = 18,002) and the lowest in studies describing populations from Europe (4.3%, n = 7,858). The overall odds ratio for patients with diabetes to be among subjects with periodontitis as compared to those without periodontitis was 2.27 (95% CI [1.90;2.72]). A substantial variability in the definitions of periodontitis, combination of self-reported and clinically assessed diabetes, lack of confounding for diabetes control in included studies introduces estimation bias. CONCLUSIONS: The overall prevalence and odds of having diabetes are higher within periodontitis populations compared to people without periodontitis. Self-reported diabetes underestimates the prevalence when compared to this condition assessed clinically. Geographical differences were observed: the highest diabetes prevalence among subjects with periodontitis was observed in studies conducted in Asia and the lowest in studies originating from Europe.