Evidence that periodontal treatment improves diabetes outcomes: A systematic review and meta-analysis

Context: The effect of periodontal therapy on diabetes outcomes has not been established. Objective: This update examines the effect of periodontal treatment on diabetes outcomes. Data sources: Literature since October 2009 using MEDLINE. Study eligibility criteria: Published RCTs including periodontal therapy for diabetic subjects, a metabolic outcome, an untreated control group, and follow-up of 3 months. Data extraction: Pre-defined data fields, including study quality indicators were used. Data synthesis: A search revealed 56 publications of which 9 met inclusion criteria. Mean change of HbA1c from baseline was compared across treatment groups. Pooled analysis was based on random effects models. Results: A meta-analysis indicated a mean treatment effect of -0.36% HbA1c (CI -0.54, -0.19) compared to no treatment after periodontal therapy (p < 0.0001). Heterogeneity tests revealed only minimal evidence of publication bias (I² = 9%). Limitations: Small sample size and high risk of bias remain problematic for studies of this type. Periodontal therapy varied considerably. Conclusion: The modest reduction in HbA1c observed as a result of periodontal therapy in subjects with type 2 diabetes is consistent with previous systematic reviews. Despite this finding, there is limited confidence in the conclusion due to a lack of multi-centre trials of sufficient sample size are lacking.