C-Reactive Protein, Neutrophil-to-Lymphocyte Ratio and Periodontal Status in Patients with and Without a History of Ischemic Stroke: A Cross-Sectional Study

Background/Objectives: Periodontitis has been linked to ischemic stroke through systemic inflammation, but the evidence remains inconsistent. We examined whether C-reactive protein (CRP), the neutrophil-to-lymphocyte ratio (NLR) and periodontal status are associated with a history of ischemic stroke. Methods: This retrospective cross-sectional study included 346 adults aged 30–82 years who underwent a full-mouth periodontal examination at a military hospital in Sibiu, Romania, between May 2022 and October 2024. Associations were estimated with Firth penalized logistic regression adjusted for age and sex, and discrimination was described with receiver operating characteristic curves. Results: Twenty-four patients (6.9%) had a history of ischemic stroke and 215 (62.1%) had periodontitis. CRP and NLR were higher in patients with prior stroke (median 13.5 vs. 5.0 mg/L and 11.6 vs. 4.6) and remained associated with stroke after adjustment (NLR: odds ratio [OR] 1.62 per unit, 95% confidence interval [CI] 1.40–1.96; CRP: OR 1.43 per mg/L, 95% CI 1.28–1.64). Periodontitis was not significantly associated with stroke (adjusted OR 1.74, 95% CI 0.71–4.83), CRP or NLR. CRP and NLR were strongly correlated (ρ = 0.94), and their separate contributions could not be distinguished. Conclusions: A history of ischemic stroke was associated with higher CRP and NLR but not with periodontal status. Because of the cross-sectional design and the small number of events, these markers may reflect the consequences of stroke and should not be interpreted as predictors of stroke risk.