Periodontitis and renal function decline in type 2 diabetes: a prospective cohort study

This study aimed to investigate the effect of periodontitis on renal function in patients with type 2 diabetes mellitus (T2D) and to explore the potential underlying pathways. A cohort of 73 patients with poorly controlled T2D who received diabetes care was monitored for six months. The association between the changes in renal function and periodontal parameters at baseline was assessed using regression analysis. Causal mediation analysis was performed to examine the effect of periodontitis on renal function mediated by glycemic control. Of the participants, 57 (78.0%) had stage III or IV periodontitis. Hemoglobin A1c levels improved significantly, from 9.5 ± 1.9% to 7.6 ± 1.4% while estimated glomerular filtration rate (eGFR) declined from 76.8 ± 23.7 to 71.8 ± 21.6 mL/min/1.73 m² (p < 0.001). eGFR decline was significantly associated with periodontitis stage, periodontal epithelial surface area, and periodontal inflamed surface area. Glycemic control did not significantly mediate this association between periodontitis and eGFR decline, whereas the direct effect of periodontitis remained significant. These findings suggest that periodontitis may contribute to renal function decline in patients with T2D, partly through pathways independent of glycemic control.