Periodontal disease and glycaemic control in diabetics

It is estimated that in 2014 around 387 million people worldwide were affected by diabetes and this expected to reach 592 million by 2035. Poorly controlled diabetes is also a recognised risk factor for periodontal disease and in recent years studies have suggested a bi-directorial relationship between periodontal disease and glycaemic levels.

The aim of this systematic review was to assess periodontal treatment in type2 diabetic patients reduces glycaemic and fasting plasma glucose levels.

Methods

Searches were conducted in the Medline, Embase, CINHAL and Cochrane Central databases. Randomised controlled trials (RCTs) studying the effectiveness of periodontal therapy on glycaemic control and/or fasting plasma glucose level in type 2 DM with periodontitis and published in English were considered. Studies were selected and data abstracted by two reviewers acting independently. Risk of bias was assessed.

The primary outcome was change in HbA1c level with change in fasting plasma glucose as a secondary outcome.

Results

7 studies involving a total of 940 patients were included in this review.
The risk of bias across the studies was considered to be moderate.
All of the studies showed a reduction in HA1c after three to four months follow-up.
A significant reduction of HbA1c was seen in the pooled analysis between the intervention and control group of: 0.48 (95%CI; 0.18 -0.78) was seen at 3 months and a mean difference of 0.53 (95%CI; 0.24, -0.81) at the end of the intervention period.
There was a significant reduction of fasting plasma glucose level, 8.95 mg/dl (95%CI: 4.30-13.61) in the intervention group after the end of the intervention.

Conclusions

The authors concluded: –

The meta-analysis result supports the effectiveness of periodontal therapy in glycaemic control in type 2 diabetic patients and periodontitis. However, large sample size Randomized controlled trials must be done to confirm this association.

Comments

Since 1990 there have been in excess of 20 reviews of this topic and with the recent publication of a substantive update of the Simpson et al Cochrane review in November 2015 the need for this new review is questionable.

This new review has searched a number of major databases but only includes 7 studies compared with the 35 studies included in the Cochrane review. Only 3 of the studies included in this new review are included in the Cochrane review and it is interesting to note important variation is the assessment of risk of bias between the two sets of authors. Two of the included studies are considered to be at low risk of bias for all the assessment criteria by the authors of this new review while the Cochrane reviewers have assessed some elements of these studies at high or unclear risk of bias. These important differences probably account for the authors overall assessment of the available evidence as moderate compared with the Cochrane reviewers assessment that the available evidence is of low quality. This new review adds little to the available evidence on this topic. The Cochrane review currently provides the best overview of this area and they concluded.

There is low quality evidence that the treatment of periodontal disease by SRP does improve glycaemic control in people with diabetes, with a mean percentage reduction in HbA1c of 0.29% at 3-4 months; however, there is insufficient evidence to demonstrate that this is maintained after 4 months.

There was no evidence to support that one periodontal therapy was more effective than another in improving glycaemic control in people with diabetes mellitus.