Periodontal Inflammatory Burden and Multi-Organ Microvascular Impairment in Type 2 Diabetes: A Cross-Sectional Observational Study

Periodontitis and type 2 diabetes mellitus (T2DM) are linked through systemic inflammation and endothelial dysfunction, yet it remains uncertain whether periodontal inflammatory burden independently reflects early, multi-organ microvascular vulnerability beyond glycemic exposure. This study aimed to assess the independent association between periodontal inflammatory burden, measured by PISA, and retinal microvascular impairment on OCT-A, and to examine relationships with renal trajectories, small-fiber neuropathy, and inflammatory/endothelial biomarkers. This cross-sectional observational study included 285 never-smoking adults with T2DM. The primary outcome was a pre-specified OCT-A microvascular impairment composite. Secondary outcomes included eGFR slope and log(UACR) slope, corneal nerve fiber length (CNFL), and a multi-organ microvascular burden score. Biomarkers comprised hsCRP, IL-6, sICAM-1, sVCAM-1, sE-selectin, PAI-1, angiopoietin-2 (Ang-2), and vWF:Ag. Multivariable linear regression estimated associations per 1 SD higher PISA, adjusting for age, sex, diabetes duration, HbA1c, CGM time in range, CGM coefficient of variation, systolic blood pressure, LDL cholesterol, BMI, and medication classes (SGLT2 inhibitors, GLP-1 receptor agonists, ACEi/ARB, statins). False discovery rate (FDR) control (q = 0.10) was applied for secondary endpoints. Higher PISA was independently associated with worse OCT-A microvascular impairment (adjusted β = 0.138, 95% CI 0.061–0.216; p = 0.0005). Although statistically significant, the effect sizes were modest in magnitude, and their translation into clinically meaningful differences in microvascular outcomes warrants investigation in prospective settings. Higher PISA was also associated with greater multi-organ microvascular burden (β = 0.101, 95% CI 0.040–0.163; p = 0.0014; FDR q = 0.005) and lower CNFL (β = −0.224, 95% CI −0.397 to −0.052; p = 0.0113; FDR q = 0.023). PISA was associated with higher levels of inflammatory and endothelial activation/injury biomarkers (all FDR q < 0.10). In this cross-sectional study, periodontal inflammatory burden was independently associated with quantitative retinal microvascular impairment, lower corneal nerve fiber length, and a consistent pattern of endothelial activation biomarker elevations in never-smoking adults with T2DM. The clinical significance of the observed effect sizes requires further evaluation, and longitudinal studies are needed to establish temporality.