Association of Simple Hematological Parameters with Disease Manifestations, Activity, and Severity in Patients with Systemic Sclerosis

Introduction/objectives: Neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), mean platelet volume (MPV), and red cell distribution width (RDW) may potentially reflect inflammatory status in systemic autoimmune diseases. The aim of this study is to investigate the association between these proposed markers and disease manifestations, activity, and severity in systemic sclerosis (SSc).

Method: We conducted a cross-sectional study of 69 systemic sclerosis (SSc) patients and 50 healthy volunteers in a single center. Adult patients with SSc and healthy controls were compared in terms of NLR, MLR, MPV, RDW, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP). Venous blood samples were drawn after at least 8 h of fasting in the morning. Extension of skin fibrosis was evaluated by using modified Rodnan skin score (mRSS). Disease severity and activity were assessed by Medsger disease severity and European Scleroderma Trials and Research Group (EUSTAR) disease activity scores, respectively. Associations of disease manifestations, clinical, laboratory, and capillaroscopic findings, mRSS, and the disease activity and severity scores with the proposed hematological markers were evaluated. Multiple regression models were generated for significant associations.

Results: The neutrophil number was higher (p = 0.004) and lymphocyte number was lower (p < 0.001) in SSc group compared to controls. SSc group also had higher NLR, MLR, and RDW. In multiple logistic regression, only the NLR (regression coefficient = 3.49, p = 0.031) and CRP (regression coefficient = 0.17, p = 0.037) remained significantly different between SSc and healthy control groups (Cox and Snell R = 0.243, Nagelkerke R = 0.337, p < 0.001). NLR and MLR positively correlated with mRSS, EUSTAR score, and CRP. MLR also positively correlated with Medsger score. Higher monocyte counts independently predicted higher EUSTAR and Medsger scores in multiple linear regressions. Patients with digital ulcers had higher NLR and MLR. We did not find any difference in MPV values between SSc and healthy control groups.

Conclusions: Globally available and inexpensive hematological tests, particularly the NLR and MLR, may be associated with vascular and cutaneous manifestations as well as disease activity and severity in SSc.Key Points• Monocyte count itself independently predicted higher activity and severity scores in SSc.• Globally available and inexpensive hematological markers, particularly the NLR and MLR, may have an association with vascular and cutaneous manifestations as well as disease activity and severity in patients with SSc.