Preliminary evaluation of the impact of periodontal treatment on markers of glycaemic control in dogs with diabetes mellitus: A prospective, clinical case series.

Background: Periodontal disease (PD) can adversely affect glycaemic control in humans. However, it is unknown if a similar association exists in dogs.

Methods: Ten client-owned dogs with poorly regulated diabetes mellitus (DM) and PD were prospectively enrolled. A complete blood count, serum biochemistry, urinalysis and measurement of C-reactive protein, interleukin-6 (IL-6), tumour necrosis factor-α, haemoglobin A1c (HbA1c) and fructosamine concentrations were performed before periodontal treatment (PT) and monthly thereafter for 3 months. A periodontal disease severity score (PDSS) was determined during PT. The effects of time post-PT and PDSS on markers of inflammation and glycaemic control were determined by generalised estimating equation analysis.

Results: HbA1c (mean; 95% confidence interval [CI]) decreased 3 months post-PT (32.1 mmol/mol; 21.1-43.1 mmol/mol vs. 44.3 mmol/mol; 36.4-52.0; p = 0.003). PDSS at enrolment was significantly (p = 0.031) positively associated with HbA1c concentration. Due to a significant (p < 0.001) interaction between PDSS and time post-PT in the analysis of fructosamine, dogs with low (1-3) PDSS and high (7-9) PDSS were analysed separately. Fructosamine (mean; 95% CI) significantly decreased 1 month post-PT (570 μmol/L; 457-684 μmol/L vs. 624 μmol/L; 499-748; p = 0.001) in the high PDSS group but not in the low PDSS group. Fructosamine concentration upon enrolment and PDSS were correlated (r = 0.73, p = 0.017). IL-6 concentration significantly decreased 3 months post-PT (9.9 pg/mL; 8.5-11.3 pg/mL vs. 11.2 pg/mL; 9.7-12.7; p = 0.002).

Limitations: Limitations of the study included the small number of dogs, the lack of a control group and the inability to assess PDSS during follow-ups.

Conclusions: These findings support a potential detrimental interaction between PD and DM. The apparent beneficial effect of PT on markers of glycaemic control was most conspicuous in dogs with more severe PD.