Baseline HbA1c Level Influences the Effect of Periodontal Therapy on Glycemic Control in People with Type 2 Diabetes and Periodontitis: A Systematic Review on Randomized Controlled Trails

INTRODUCTION: The question of whether periodontal therapy is an effective strategy for achieving glycemic control in people with type 2 diabetes mellitus (T2DM) and periodontitis continues to be open to debate. To clarify this issue, we conducted a systematic review and meta-analysis. METHODS: A systematic literature search of randomized controlled trials (RCTs) was carried out by searching four electronic databases and four journals up to April 2020. RCTs that evaluated the effect of periodontal therapy on glycemic control in people with T2DM were included. RESULTS: A total of 23 RCTs were included in this systematic review and meta-analysis. We found that after 3 and 6 months, periodontal therapy could significantly reduce glycosylated hemoglobin (HbA1c) level (3-month: weighted mean difference [WMD] − 0.514, 95% confidence interval [CI] − 0.730, − 0.298, p = 0.000; 6-month: WMD − 0.548, 95% CI − 0.859, − 0.238, p = 0.000). However, huge heterogeneity existed. Further analyses on 11 potential sources of heterogeneity found that baseline HbA1c of the included studies was the most significant factor causing heterogeneity. The benefit of periodontal therapy on glycemic control was much more obvious in studies with a higher baseline HbA1c level than in those with a lower baseline HbA1c level. CONCLUSIONS: Periodontal therapy significantly contributed to glycemic control in T2DM patients, especially in patients with higher baseline HbA1c level. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13300-021-01000-6.