Heparin-binding protein levels predict unfavorable outcome in COVID-19 pneumonia: A post-hoc analysis of the SAVE trial

We aimed to evaluate heparin-binding protein (HBP) as a marker of prognosis of unfavorable outcome in COVID-19 pneumonia. This was a post hoc analysis of the SAVE clinical trial investigating anakinra treatment, guided by suPAR (soluble urokinase plasminogen activator receptor) levels ≥6 ng/mL, for the prevention of severe respiratory failure in hospitalized patients with COVID-19 pneumonia. Baseline HBP plasma levels were measured in 534 patients by fluorescence dry quantitative immunoassay using the Jet-iStar 800 analyzer. Concentrations higher than 35 ng/mL predicted 30-day mortality with a moderate specificity of 53.3% and negative predictive value 78.1%; sensitivity was low (29.0%). After multivariate Cox analysis, HBP higher than 35 ng/mL was an independent predictor of 30-day unfavorable outcome (adjusted hazard ratio, 1.77; 95% CI, 1.06-2.94; P = 0.028) and these patients were also at greater risk of death after 90 days (hazard ratio, 1.85; 95% CI, 1.25-2.74; P = 0.002). The cutoff was not predictive of development of severe respiratory failure, septic shock or acute kidney injury. Among patients with baseline HBP levels higher than 35 ng/mL, anakinra treatment was associated with decreased mortality (7.2%) versus comparators (18.1%; P < 0.001). Results confirm that HBP may be an early biomarker of poor outcome among preselected patients at risk from COVID-19 pneumonia.ClinicalTrials.gov registration NCT04357366.