Higher Neutrophil Count Linked to Mortality in Systemic Sclerosis-Related Interstitial Lung Disease

A higher neutrophil count may predict worse disease course and higher long-term mortality in patients with systemic sclerosis-related interstitial lung disease (SSc-ILD), according to study results presented at the American College of Rheumatology (ACR) Convergence 2020, held virtually from November 5 to 9, 2020.

Patients with SSc have a prominent neutrophil gene expression signature, but studies related to the pathophysiologic role of neutrophils in SSc are lacking. Therefore, in the current study, researchers examined the prognostic significance of neutrophil counts in SSc-ILD by prospectively obtaining neutrophil counts at the baseline visit of the Scleroderma Lung Study (SLS) II (ClinicalTrials.gov Identifier: NCT00883129).

Participants had clinically significant SSc-ILD, with a disease duration of fewer than 7 years. A joint model that combined mixed effects and survival models was used to examine the relationship between baseline blood neutrophil count and serially obtained percent predicted forced vital capacity (FVC%) as well as modified Rodnan skin scores (mRSS) from 3 to 12 month visits after adjustment for baseline severity and treatment group. To evaluate the association between neutrophil count and long-term mortality, the researchers created Cox proportional hazard models.

Of the 142 patients enrolled in SLS II, 134 (94.3%) had available baseline neutrophil counts. The majority of patients had diffuse cutaneous disease (59%) and the mean disease duration was 2.6 years. Based on the course of the FVC% from 3 to 12 months, higher neutrophil count predicted worsening of SSc-ILD (baseline neutrophil count, -1.11; 95% CI, -1.15 to -1.08; P =.030). After adjustment for age, baseline neutrophil count predicted an increased risk for mortality (hazard ratio, 2.02; 95% CI, 1.02-4.01; P =.045). For the mortality analysis, the median follow-up was 3.4 years. However, neutrophil count did not predict changes in mRSS.

“Our findings were independent of treatment with cyclophosphamide or mycophenolate,” the researchers wrote. “Neutrophils, largely underinvestigated in SSc, might play a role in pathogenesis of SSc and warrant further mechanistic studies.”

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Wareing N, Li N, Volkmann E, et al. Serum neutrophil count predicts progression of interstitial lung disease and mortality in patients with systemic sclerosis related interstitial lung disease. Presented at: ACR Convergence 2020; November 5-9, 2020. Abstract 0384.