Association of hematological ratios with psoriasis: a nationwide retrospective cohort study

Background: Psoriasis is a common skin disorder linked to systemic inflammation and immune dysregulation. It is believed to involve activated T cells and neutrophils. Recent research has highlighted the potential role of hematological ratios, such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), eosinophil-to-lymphocyte ratio (ELR), eosinophil-to-neutrophil ratio (ENR), and eosinophil-to-monocyte ratio (EMR), as markers for inflammatory skin diseases, including psoriasis. Objectives: We aimed to investigate hematological ratios between children and adults, patients and controls, and patients with moderate-to-severe and mild psoriasis. Materials and Methods: This national retrospective cohort study included over 16,000 psoriasis patients in Israel. Patients with comorbidities influencing blood counts were excluded. Ratios were calculated from blood counts taken within 30 days of diagnosis. Multivariable logistic regression, including age, gender, ethnicity, smoking status, and socioeconomic status, was performed. Results: Findings revealed age-specific variations in blood counts, hematological ratios, and differences between mild and moderate–severe patients and patients versus controls. Moderate–severe psoriasis patients had elevated neutrophil and eosinophil counts (4.57 vs. 4.25, P < 0.001, and 0.24 vs. 0.22, P = 0.047, respectively), as well as increased NLR (2.46 vs. 2.29, P < 0.001). Multivariable logistic regression analysis confirmed the significance of neutrophil and platelet counts as well as NLR and PLR in predicting psoriasis severity. Limitations: This was a retrospective study without subjective data on disease severity. Conclusion: This study highlights hematologic ratios' diagnostic and prognostic potential in psoriasis.