Predictors of disease severity, length of hospitalization, and recurrence in inpatients with single-organ cutaneous small vessel vasculitis.

There is a lack of systematic studies on single-organ cutaneous small vessel vasculitis (SOCV). To evaluate prognostic clinical and laboratory parameters, including systemic immune-inflammation biomarkers (SIIB) in SOCV inpatients. This study investigated the clinical and laboratory data of 178 inpatients. Blood tests were performed at baseline. SIIB were assessed based on neutrophil-to-lymphocyte ratio (NLR) and pan-immune-inflammation value (PIV). Univariable and multivariable statistics were performed. Both NLR and PIV were significantly higher in SOCV patients than in healthy controls. However, the SIIB values observed in SOCV patients were as high as those in psoriasis patients. On logistic regression analysis, disease manifestation on the upper extremities strongly predicted the absence of severe disease (OR: 0.31, 95% CI: 0.13 to 0.73; p = 0.0071). Moreover, older age (OR: 2.3, 95% CI: 1.11 to 4.77; p = 0.025) and severe disease (OR: 2.4, 95% CI: 1.16 to 4.94, p = 0.018) were significant independent predictors of longer hospital stay, whereas female sex was an independent protective factor for longer hospitalization (OR: 0.52, 95% CI: 0.28 to 0.96, p = 0.038). Lower serum C3 was a strong independent predictor of disease recurrence (OR: 13.9, 95% CI 3 to 63.4; p = 0.0007). The increase in SIIB observed in patients with SOCV reflects that systemic inflammatory alterations also play a role in SOCV patients. We identified several clinical and laboratory-based independent predictors of SOCV severity, length of hospitalization, and disease recurrence that may aid prognostication of SOCV patients.