The effect of nonsurgical periodontal therapy on hemoglobin A1c levels in persons with type 2 diabetes and chronic periodontitis: a randomized clinical trial

Abstract

Importance: Chronic periodontitis, a destructive inflammatory disorder of the supporting structures of the teeth, is prevalent in patients with diabetes. Limited evidence suggests that periodontal therapy may improve glycemic control.

Objective: To determine if nonsurgical periodontal treatment reduces levels of glycated hemoglobin (HbA1c) in persons with type 2 diabetes and moderate to advanced chronic periodontitis.

Design, setting, and participants: The Diabetes and Periodontal Therapy Trial (DPTT), a 6-month, single-masked, multicenter, randomized clinical trial. Participants had type 2 diabetes, were taking stable doses of medications, had HbA1c levels between 7% and less than 9%, and untreated chronic periodontitis. Five hundred fourteen participants were enrolled between November 2009 and March 2012 from diabetes and dental clinics and communities affiliated with 5 academic medical centers.

Interventions: The treatment group (n = 257) received scaling and root planing plus chlorhexidine oral rinse at baseline and supportive periodontal therapy at 3 and 6 months. The control group (n = 257) received no treatment for 6 months.

Main outcomes and measures: Difference in change in HbA1c level from baseline between groups at 6 months. Secondary outcomes included changes in probing pocket depths, clinical attachment loss, bleeding on probing, gingival index, fasting glucose level, and Homeostasis Model Assessment (HOMA2) score.

Results: Enrollment was stopped early because of futility. At 6 months, mean HbA1c levels in the periodontal therapy group increased 0.17% (SD, 1.0), compared with 0.11% (SD, 1.0) in the control group, with no significant difference between groups based on a linear regression model adjusting for clinical site (mean difference, -0.05% [95% CI, -0.23% to 0.12%]; P = .55). Periodontal measures improved in the treatment group compared with the control group at 6 months, with adjusted between-group differences of 0.28 mm (95% CI, 0.18 to 0.37) for probing depth, 0.25 mm (95% CI, 0.14 to 0.36) for clinical attachment loss, 13.1% (95% CI, 8.1% to 18.1%) for bleeding on probing, and 0.27 (95% CI, 0.17 to 0.37) for gingival index (P < .001 for all).

Conclusions and relevance: Nonsurgical periodontal therapy did not improve glycemic control in patients with type 2 diabetes and moderate to advanced chronic periodontitis. These findings do not support the use of nonsurgical periodontal treatment in patients with diabetes for the purpose of lowering levels of HbA1c.

Trial registration: clinicaltrials.gov Identifier: NCT00997178.

Figure 1

DPTT Participant Flow Chart ^a Essential Dental Care – defined as participants needing treatment of extensive tooth decay, tooth abscesses, or other oral infections: ^b Non-steroidal anti - inflammatory drug

Figure 2

Hemoglobin A_1c Levels at Baseline and Follow-up Mean values and standard errors are presented at each visit. P-values comparing 6-month change in Hb A_1c between the two treatment groups were based on t-tests from linear regression models with 6-month HbA₁c change as a dependent variable, treatment group and Clinical Site as covariates.

Figure 3

Periodontal Measurements at Baseline and Follow-up (Per Protocol) Mean values and standard errors are presented at each visit. P-values comparing 6-month changes in periodontal outcomes between the two treatment groups were based on t-tests from linear regression models with 6-month periodontal change as a dependent variable, treatment group and Clinical Site as covariates.