Platelet-to-lymphocyte ratio and neutrophil-to-lymphocyte ratio as potential makers for digital ulcers and interstitial lung disease in patients with systemic sclerosis: cross-sectional analysis of data from a prospective cohort study

In this study, we aimed to investigate the association of platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) with clinical manifestations in patients with systemic sclerosis (SSc). We conducted a cross-sectional analysis of data collected from a cohort study of 114 female patients with SSc and of 304 age-matched, healthy, female controls recruited from a tertiary rheumatology center. Patients with digital ulcers (DU) included those with either active or healed ulcers. Interstitial lung disease (ILD) was diagnosed on detection of diffuse ground-glass opacity or pulmonary fibrosis on chest X-ray or on high-resolution computed tomography. Patients with SSc had significantly higher PLR and NLR than ealthy controls. Of 114 patients with SSc, 35 (30.7%) and 54 (47.4%) patients had DU (active: 12, healed: 23) and ILD, respectively. PLR and NLR in SSc patients with concurrent DU or ILD were significantly higher than that in those without these respective complications. The PLR (OR = 1.008, 95% CI 1.002–1.015), but not the NLR, was independently associated with the presence of DU in SSc patients, based on multivariable logistic regression models. Additionally, both PLR (OR = 1.008, 95% CI 1.001–1.014) and NLR (OR = 1.515, 95% CI 1.066–2.155) correlated independently with the presence of ILD. However, both the PLR and NLR showed no significant association with the modified Rodnan skin score, pulmonary arterial hypertension, and gastrointestinal involvement. Our results suggest that PLR and NLR could be considered as potential biomarkers of DU and ILD, in patients with SSc.