The Prognostic Value of the Naples Prognostic Score in Depression: Association with Prevalence and Mortality

Background Depressive disorder is a widespread mental health condition, distinguished by symptoms such as persistent low mood, loss of interest, diminished energy, and changes in sleep and appetite. The Naples Prognostic Score (NPS), which combines biomarkers related to inflammation and nutritional status, has been shown to have prognostic value in several diseases. This study used data from the National Health and Nutrition Examination Survey (NHANES), which was carried out between 2007 and 2018, to examine the link between NPS, depression prevalence, and mortality in people with depression. Methods The cross-sectional analysis involved 29,655 participants, with 2,688 individuals diagnosed with depression, and 2,190 participants followed for mortality outcomes. The Patient Health Questionnaire-9 (PHQ-9) was used to measure depression, and blood albumin, total cholesterol, the neutrophil-to-lymphocyte ratio (NLR), and the lymphocyte-to-monocyte ratio (LMR) were used to calculate NPS. The relationship between NPS and depression was examined using weighted logistic regression, while the relationship between NPS and mortality in depressed patients was evaluated using Cox proportional hazards models, which controlled for clinical and demographic variables. Results An increased likelihood of depression (OR = 1.32, 95% CI: 1.09–1.60, p < 0.01) and a higher risk of death from all causes (HR = 4.54, 95% CI: 2.24–9.21, p < 0.01), heart disease (HR = 8.39, 95% CI: 2.85–24.71, p < 0.01), malignant neoplasms (HR = 5.10, 95% CI: 1.21–21.41, p = 0.03), diabetes (HR = 5.66, 95% CI: 1.44–22.24, p = 0.01), and hypertension (HR = 6.68, 95% CI: 1.69–26.40, p = 0.01) were all significantly correlated with higher NPS scores. Conclusion This study highlights the clinical relevance of the NPS in predicting both the prevalence of depression and its associated mortality risk. The NPS offers a valuable tool for early risk stratification and can support the development of personalized management strategies for individuals with depression, potentially improving their long-term health outcomes.