In Reply Dr Merchant suggests that the relationship between periodontal therapy and glycemic control in persons with type 2 diabetes may vary by BMI. In the DPTT, participants were predominantly obese (72% had a BMI ≥30). Subgroup analyses of different BMI cut points found no effect of periodontal therapy on glycemic control (P ≥ .10) in any subgroup examined. Differences in baseline periodontitis levels, use of antibiotics, and race/ethnicity may also explain the inconsistent findings among studies.
Engebretson SP, Hyman LG, Michalowicz BS. Hemoglobin A1c Levels Among Patients With Diabetes Receiving Nonsurgical Periodontal Treatment—Reply. JAMA. 2014;311(18):1921-1922. doi:10.1001/jama.2014.2231