The Naples Prognostic Score Is Independently Associated with Paroxysmal Atrial Fibrillation: A Retrospective Case–Control Study

Background and objectives: Paroxysmal atrial fibrillation (PAF) is a common arrhythmia associated with adverse cardiovascular outcomes. Inflammation and nutritional imbalance contribute to arrhythmogenesis. The Naples Prognostic Score (NPS), derived from inflammatory and nutritional laboratory markers, has shown prognostic value in cardiovascular disease, but its association with PAF in outpatients has not been evaluated. This study assessed whether NPS is independently associated with the presence of PAF in a cardiology outpatient population. Methods: This retrospective case–control study included 429 patients evaluated between January 2023 and January 2025. Among them, 155 had documented PAF and 274 patients in sinus rhythm served as controls. Demographic, laboratory, and echocardiographic data were collected. NPS was calculated using serum albumin, total cholesterol, neutrophil-to-lymphocyte ratio, and lymphocyte-to-monocyte ratio. Multivariable logistic regression identified variables independently associated with PAF. Results: Among patients with calculable NPS (n = 386), NPS was higher in the PAF group (1.92 ± 0.98 vs. 0.96 ± 0.93; p < 0.001), and high NPS was more frequent (26.0% vs. 7.8%; p < 0.001). In multivariable analysis, NPS remained independently associated with documented prevalent PAF (OR 2.46; 95% CI 1.79–3.36; p < 0.001). Conclusions: NPS was independently associated with documented prevalent PAF in this outpatient cohort. These findings do not establish diagnostic or predictive utility, and prospective longitudinal studies are required to determine whether NPS is associated with incident PAF.