Association of Inflammation-Based Ratios with Endothelial Dysfunction Markers and Clinical Parameters in Limited Cutaneous Systemic Sclerosis

<b>Background</b>: Limited cutaneous systemic sclerosis (lcSSc) is an autoimmune disease with a wide range of different biomarkers, while inflammation-based ratios have been less extensively investigated. This study aimed to evaluate the associations between inflammation-based ratios, disease-specific parameters, and endothelial dysfunction, as well as to assess the predictive role of inflammation-based ratios in lcSSc. <b>Methods</b>: A total of 38 lcSSc patients and 38 matched controls with primary Raynaud's phenomenon were analyzed at baseline regarding inflammation-based ratios, lcSSc-specific parameters, and parameters of endothelial dysfunction. LcSSc patients were prospectively observed during a 3-year follow-up period in which lcSSc complications were recorded annually. <b>Results</b>: LcSSc patients had a significantly higher neutrophil-to-lymphocyte ratio, monocyte-to-lymphocyte ratio (MLR), fibrinogen-to-albumin ratio, monocyte/high-density lipoprotein (HDL) ratio, and neutrophil/HDL ratio versus controls (all <i>p</i> < 0.05). During follow-up, the MLR, C-reactive protein (CRP)/albumin ratio, monocyte/HDL ratio, and neutrophil/HDL ratio increased significantly (all <i>p</i> < 0.05) in lcSSc patients. The monocyte/HDL ratio correlated positively with the DETECT score step 2 (r = 0.453, <i>p</i> = 0.032) and negatively with the UCLA SCTC GIT total score (r = -0.469, <i>p</i> = 0.024). The CRP/albumin ratio correlated significantly with the EUSTAR index (r = 0.473, <i>p</i> = 0.024) and the fibrinogen-to-albumin ratio correlated with asymmetric dimethylarginine (r = 0.452, <i>p</i> = 0.044). The MLR and CRP/albumin ratio were associated with development of pulmonary arterial hypertension (<i>p</i> = 0.036, <i>p</i> = 0.006), and the lymphocyte/HDL ratio was associated with newly developed interstitial lung disease (<i>p</i> = 0.004). <b>Conclusions</b>: Readily available inflammation-based ratios may reflect vascular and inflammatory activity and could contribute to risk stratification for pulmonary complications in lcSSc; however, these exploratory findings require confirmation in larger cohorts.