Periodontitis and Type 2 Diabetes: What Impact on A1C?

Recent months have witnessed increased attention to the role of periodontitis in glycemic control of type 2 diabetes (T2DM). In December 2013, the European Foundation for Periodontology (EFP) and the American Academy of Periodontology (AAP) issued a consensus report on periodontitis and systemic diseases.¹ What does the report mean for your patients with T2DM?

EFP/AAP Consensus Report

“Over the past 20 years, consistent and robust evidence has emerged that severe periodontitis adversely affects glycaemic control in diabetes and glycaemia in non-diabetes subjects,”¹ the authors write. They highlight the following research:

- Randomized controlled trials (RCTs) that link 3 months of mechanical periodontal therapy to 0.4% reductions in HbA1C. This effect, according to the authors, equates to adding a second medication to a patient’s antidiabetes regimen. 

- Severe periodontitis is associated with progressively worsening HbA1C (A1C) in tandem with worsening periodontal disease. 

- Moderate to severe periodontitis is associated with increased risk of developing T2DM and its complications (particularly, cardiovascular and renal). 

Recommended guidelines include:

- Oral health education for all diabetic patients, especially regarding increased risk of periodontal disease, and the link between periodontitis, more difficult glycemic control, and increased risk of diabetes complications.

- Comprehensive oral and periodontal exams for all patients with diabetes (regardless of type), beginning at ages 6 to 7 for children.

- Baseline periodontal exams for patients with newly diagnosed diabetes, with annual follow-up exams for all.

- Prompt treatment for overt periodontal disease (loose teeth, teeth spacing, gingival abscesses), tooth loss, and other oral problems common in T2DM (dry mouth, burning mouth, oral candidiasis, poor oral wound healing).

The report recommends professional mechanical debridement and effective home care in diabetic patients, and calls for larger, longer-term RCTs. 

Controversy: Effect Nil in Largest Study

About the same time as the EFP/AAP report, the results of the largest RCTs to date on this topic were published in JAMA, and questioned the role of periodontal therapy in glycemic control.²

“These findings do not support the use of nonsurgical periodontal treatment in patients with diabetes for the purposes of lowering levels of HbA1C,” concluded the authors of the Diabetes and Periodontal Therapy Trial (DPTT).²

The 6-month, single-masked, 5-center trial followed 514 participants with moderate to severe periodontitis and T2DM, on stable medication doses and with A1C between 6% and 9%. The treatment group received scaling and root planing (mechanical plaque removal), chlorhexidine rinse, and supportive periodontal therapy at 3 and 6 months. Controls received no periodontal treatment.

Results included:

- Failure to achieve target 6-month A1C lowering of 0.6% or greater, leading to early ending of recruitment. 

- No significant difference between control and treatment groups (P = .55).

- A1C at 6 months increased by 0.17% in the treatment group, and 0.11% among controls. 

- Treatment significantly improved periodontal measures (P < .001).

“The consensus statements relied on data from small studies that were underpowered. Results of small randomized trials are not always reproducible,” explained first author Steven Engebretson, DMD, College of Dentistry, New York University.    

Nevertheless, Engebretson emphasizes that patients with diabetes are at increased risk for periodontitis, and that periodontal therapy should be recommended.

EFP Response 

In response, the EFP issued a statement questioning the results of the DPTT.³ The EFP’s argument centers on the study’s periodontal outcomes, which they believe were substandard in controlling local infection and inflammation.

“Whilst improvements in periodontal outcomes may have been statistically significant, they were not clinically significant,” they argue. “If periodontal therapy is unsuccessful in controlling periodontal infection, then the effects of periodontal treatment on the metabolic control of diabetes cannot be properly assessed.”

The EFP also pointed out that nearly all of the patients in the DPTT had HbA1C levels below 9.0%, so they may not have been representative of patients who might benefit most from periodontal treatment. 

Take-Away for Primary Care

“Our advice has not changed until we have a definitive study in which the periodontal treatment has worked,” commented Iain Chapple, PhD, College of Medical & Dental Sciences, Birmingham UK, who was first author of the EFP/AAP report.

While awaiting resolution from investigators, clinicians can take a practical clue from the fact that their research colleagues agree on at least one thing: Education for your patients with diabetes about proper oral health and treatment of periodontitis is important, at the very least to save their teeth.

References:

• Chapple ILC, Genco R, and the working group 2 of the joint EFP/AAP workshop. Diabetes and periodontal diseases: consensus report of the Joint EFP/AAP Workshop on Periodontitis and Systemic Diseases. J Periodontol. 2013;84(4 suppl):S106-S112. Full text available at: http://www.joponline.org/doi/pdf/10.1902/jop.2013.1340011
   
• Engebretson SP, Hyman LG, Michalowicz BS, et al. The effect of nonsurgical periodontal therapy on hemoglobin A1C levels in persons with type 2 diabetes and chronic periodontitis: a randomized clinical trial. JAMA. 2013;310:2523-2532. doi:10.1001/jama.2013.282431.

• European Federation of Periodontology. Official Statement on NIH Study. December 18, 2013. Personal email communication with Iaian Chapple.