Association of Elevated Platelets and CRP With Severe Disease and Poor Survival in Systemic Sclerosis.

Abstract

Elevated C-reactive protein (CRP) in systemic sclerosis (SSc) has been linked with severe disease and worse survival, but the role of platelet levels remains unclear. This study examined whether elevated platelets, CRP, or both are associated with disease severity, progression, and survival in SSc. We performed a retrospective study of adult SSc patients seen from 1996 to 2022. Using the first blood draw after symptom onset, patients were categorized into four groups using cutoffs of ≥ 330,000/μL for platelets and ≥ 6.0mg/L for CRP: 1) normal platelet/normal CRP (NP/NC), 2) normal platelet/elevated CRP (NP/EC), 3) elevated platelet/normal CRP (EP/NC), 4) elevated platelet/elevated CRP (EP/EC). 139 were included (84 (60%) NP/NC, 33 (24%) NP/EC, 10 (7%) EP/NC, and 12 (9%) EP/EC). The EP/EC had the highest rates of Scl-70 antibody positivity, diffuse skin involvement, myocarditis/cardiomyopathy, dysphagia, gastric antral vascular ectasia, joint contractures, and digital ulcers (p<0.05). NP/NC had the best baseline forced vital capacity (FVC), which remained stable over two years, though differences amongst groups over time were not significant. EP/EC had the highest modified Rodnan skin scores (mRSS) throughout the two-year period (p<0.05). Median survival was lowest in the EP/EC group (9.6 years vs 21.3 years in NP/NC, p<0.0001), adjusted HR 7.34 (2.40-22.41, Bonferroni-adjusted p=0.0025). Patients with isolated CRP or platelet elevation demonstrated intermediate disease severity compared with the dual-elevation group. Elevated platelets in combination with elevated CRP identifies SSc patients with severe disease and poor survival, who may warrant aggressive screening and treatment of complications.