1507-P: Dose–Response Relationship between Periodontal Inflamed Surface Area and Glycated Haemoglobin Level in Patients with Type 2 Diabetes Mellitus on Insulin Therapy and on Oral Antidiabetic Therapy

A bidirectional inflammatory link exists between periodontitis and diabetes mellitus. Diabetes increases the prevalence and severity of periodontitis and periodontitis affects glycemic control. Treatment of diabetes is with oral antidiabetic drugs (OAD), insulin or their combinations. Insulin achieves faster glycemic control and has other beneficial effects. This study was undertaken to compare the prevalence, extent and severity of periodontal disease, to correlate periodontal inflamed surface area (PISA) with Glycated Hb (HbA1c) and to find the dose response relationship between PISA and HbAic in type 2 diabetes mellitus (T2DM) on insulin therapy and on OAD therapy. The study comprised of 130 T2DM patients on oral antidiabetic drugs therapy (OAD group) and 130 T2DM patients on insulin therapy (INSULIN group). All subjects were assessed for periodontal parameters (BOP, PPD, CAL, OHI-S Index, PI Index and PISA) and systemic parameters (HbA1c, FPG, PPG). The proportion of periodontitis was lower in INSULIN group (46.2%) as compared to OAD group (83.1%). Extent and severity of periodontitis and PISA were lower in INSULIN group as compared to OAD group. HbA1c was positively correlated with PISA in OAD group(r=0.391)(p <0.001) and in INSULIN group (r=0.492) (p <0.001). A dose response relationship between PISA and HbA1c has been observed and an increase in HbA1c of 1% is associated with an increase in PISA of 195mm² (p <0.001). Multiple linear regression models showed that shifting from OAD to INSULIN results in the decrease of PISA by 605.4mm² (p <0.001). This indicates to the beneficial effects of insulin on periodontal tissues. Dose response relationship between HbA1c and PISA confirm the bidirectional relationship between diabetes mellitus and periodontal disease.