Association of Elevated Platelets and C-Reactive Protein With Severe Disease and Poor Survival in Systemic Sclerosis.

OBJECTIVE

Elevated C-reactive protein (CRP) levels in systemic sclerosis (SSc) have been linked with severe disease and worse survival, but the role of platelet levels remains unclear. This study examined whether elevated platelet levels, CRP levels, or both are associated with disease severity, progression, and survival in SSc.

METHODS

We performed a retrospective study of adult patients with SSc 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 ≥6.0 mg/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).

RESULTS

One hundred and thirty-nine patients were included (84 NP/NC [60%], 33 NP/EC [24%], 10 EP/NC [7%], and 12 EP/EC [9%]). 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, which remained stable over two years, though differences among groups over time were not significant. EP/EC had the highest modified Rodnan skin scores 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), with an adjusted hazard ratio of 7.34 (95% CI 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.

CONCLUSION

Elevated platelet levels in combination with elevated CRP levels identifies patients with SSc with severe disease and poor survival, who may warrant aggressive screening and treatment of complications.