HbA1c changes in patients with diabetes following periodontal therapy

PURPOSE: This retrospective cohort study aimed to assess the effect of nonsurgical periodontal therapy on glycated hemoglobin (HbA1c) levels in patients with both type 2 diabetes and chronic periodontitis. METHODS: The intervention cohort (IC) comprised 133 patients with type 2 diabetes who received nonsurgical periodontal treatment, while the matching cohort (MC) included 4787 patients with type 2 diabetes who visited the Department of Endocrinology and Metabolism of Asan Medical Center. The patients in each cohort were divided into 3 groups according to their baseline HbA1c level: subgroup 1, HbA1c <7%; subgroup 2, 7%≤ HbA1c <9%; and subgroup 3, HbA1c ≥9%. Changes in HbA1c levels from baseline to 6 and 12 months were analyzed. In addition, the association between changes in HbA1c levels and the number of periodontal maintenance visits was investigated. RESULTS: There were no statistically significant changes in HbA1c levels in the IC and MC or their subgroups when evaluated with repeated-measures analysis of variance. However, the IC showed maintenance of baseline HbA1c levels, while the MC had a trend for HbA1c levels to steadily increase as shown by pairwise comparisons (baseline to 6 months and baseline to 12 months). IC subgroup 1 also maintained steady HbA1c levels from 6 months to 12 months, whereas MC subgroup 1 presented a steady increase during the same period. The number of periodontal maintenance visits had no association with changes in HbA1c levels during the 1-year study duration. CONCLUSIONS: For patients with both type 2 diabetes and periodontitis, nonsurgical periodontal treatment and periodontal maintenance may help to control HbA1c levels.