Periodontal disease and glycaemic control in diabetics

A number of studies have suggested a positive relationship between treatment of periodontal disease and glycaemic control in diabetics. A number of systematic reviews of also been undertaken.

The aim of this overview was assess the findings and quality of existing systematic reviews that reported the effectiveness of periodontal treatment on the improvement of glycaemic control of patients with diabetes mellitus (DM) with periodontitis.

Methods

Searches were conducted in the Medline and Embase databases. All systematic reviews assessing the effectiveness of periodontal treatment on DM outcomes in humans were considered. Reviews that did not include meta-analysis were excluded as we reviews not published in English.

Two reviewers independently selected studies and abstracted data assessed review quality. Review quality was assessed using the Assessment of Multiple Systematic Reviews (AMSTAR) and the Overview Quality Assessment Questionnaire (OQAQ).

Results

11 systematic reviews were included.
The AMSTAR score range from 5-9 (median =7)
8 reviews included RCTs only
Sample sizes of the primary studies in the reviews ranged from 10-165 patients.
Results were consistent, favouring a reduction in HbA1c following periodontal treatment compared to those who did not receive any periodontal treatment: on average 0.46%, range from 0.24% to 1.03%.

Conclusions

The authors concluded

The results of this over-view demonstrated that important methodological limitations, including underpowered trials and publication bias, hinder the conclusion that periodontal therapy may improve glycaemic control.

Comments

This overview of systematic review of effectiveness of periodontal treatment on the improvement of glycaemic control of patients with diabetes mellitus was completed prior to the latest update of the Cochrane review on this topic (Dental Elf -11^th Nov 2015). 35 RCTs were included in the Cochrane review with just over 80% being considered to be a high risk of bias. The new Cochrane review found a mean reduction in HbA1c of 0.29%, which is at the lower end of the range reported in the overview of reviews. While this small benefit was demonstrated this was only maintained in the short-term.

This review and the Cochrane review highlight that larger higher quality trials need to be conducted to understand the potential of periodontal treatment to improve glycaemic control among people with diabetes mellitus. With a ratio of 1 systematic review having been conducted for 3 RCTs the focus for researchers should now be on the development and conduct of high quality trials rather than more systematic reviews.