Evidence Alert

Members of the American Academy of Periodontology have been alerted yesterday evening by the publication of a large (more than 500 patients were enrolled) phase 3, single-masked, multicenter, randomized, 6-month intervention study on moderate to severe chronic periodontitis patients with diabetes type 2 taking stable doses of anti-diabetic medication. Engebretson et al. 2013 report in JAMA that basic periodontal treatment, i.e., scaling and root planing, did not lead to a reduction of HbA1c levels. Instead, HbA1c levels had slightly increased after 6 months, in test subjects receiving basic periodontal treatment even slightly more (normalized mean 0.17%) than in the control group (normalized mean 0.11%) where basic treatment was postponed. The difference was not significant.

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.”

The study’s first author, Steven Engebretson, had also been the first author in a systematic review on diabetes and periodontal disease which had been formulated during the November 2012 joint AAP/EFP workshop on periodontal and systemic diseases at La Granja de San Ildefonso, Segovia, Spain. In a meta-analysis of nine, very heterogeneous, studies a significant effect size of 0.36% HbA1c (95% CI 0.66, 0.19) was observed. Authors claim that periodontal treatment (non-surgical or surgical with and without systemic or topical antibiotics) may reduce HbAc1 by a margin comparable to the effect of additional anti-diabetic pharmacotherapy and “therefore may find its place in the treatment of diabetic patients.” In the discussion, Engebretson & Kocher (2013) write,

“A major limitation, as before, is that no single randomized clinical trial reported here would be defined as a phase 3 (pivotal study), and hence, validation of these findings in a large clinical trial is needed. Results from one such study may be expected by early 2013 (ClinicalTrials.gov: NCT00997178).”

Well, it took a bit longer, but now we have got the results of the first “definitive” study. The study plan can be found here. Do we need to adjust our opinions? Of course. The study is three times larger than the largest study in Engebretson and Kocher’s systematic review of 2013 and will certainly have a nullifying effect in a new meta-analysis.

AAP officers seem to be desperate when facing the new evidence which may put their long-held claims into perspective. What does AAP president Stuart Froum write? Basic care for periodontal disease may not be enough for patients with diabetes.

“It is important to note that the nonsurgical therapy employed in this study did not eradicate periodontal disease, which may be why researchers did not see an effect on glycemic control.

“A major indicator of periodontal disease – bleeding on probing – decreased only 19 percent, suggesting that the nonsurgical therapy was not successful in controlling moderate to advanced periodontal disease. The failure to eliminate periodontal disease may be why glycemic control was not impacted.”

Well, quality of periodontal treatment in several of the previously reviewed, by Engebretson and Kocher (2013), small-scale trials was poor, to say the least. Nevertheless, a net beneficial effect on HbA1c could be ascertained. So, that may not be a striking argument. Quality of scaling and root planing in the current study by Engebretson et al. (2013) has to be scrutinized, for sure.

They explain the intervention as follows,

“Initial treatment consisted of at least 160 minutes of scaling and roort planing using curettes and ultrasonic instruments with local anaesthesia during 2 or more sessions completed within 42 days of the baseline visit. Completeness of therapy was assessed by the study therapist and confirmed by a study periodontist. After treatment, the therapist provided oral hygiene instructions and dispensed chlorhexidine gluconate (0.12% oral rinse, twice daily for 2 weeks), toothbrush, toothpaste, and dental floss. Three and 6 months after the baseline visit, participants in the treatment group received oral hygiene instructions and scaling and root planing for approximately 1 hour during a single session. Participants in the control group received only oral hygiene instructions at the baseline and 3- and 6-month visits.”

The AAP statement can be found here.

19 December 2013 @ 11:30 am.

Last modified December 19, 2013

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