Combination of fibrosis-4 score and D-dimer: a practical approach to identify poor outcome in COVID-19.

Abstract

Aim: Fibrosis-4 (FIB-4) score and D-dimer (DD) have emerged as prognostic markers in coronavirus disease 2019 (COVID-19). However, precise cutoff points remain undefined, and their combined use has been scarcely studied. We aimed to analyze FIB-4 and DD performance, individually and combined, to predict outcomes among COVID-19 patients.

Methods: From March to December 2020, hospitalized COVID-19 patients were evaluated based on clinical and laboratory tests from their first day of hospitalization. Primary outcome was inhospital mortality, and secondary outcomes included hospital stay length, ICU admission and duration, need for hemodialysis, ventilatory support, and extent of lung involvement. Optimal FIB-4 and DD cutoff points to predict mortality were established to maximize sensitivity and specificity. A sequential diagnostic strategy using both markers was subsequently evaluated.

Results: Among 518 patients (61 ± 16 years, 64% men), the inhospital mortality rate was 18%. FIB-4 outperformed DD in predicting mortality (area under the receiver operating characteristic curve: 0.76 vs. 0.65, P  = 0.003) and was chosen as the first step in sequential analysis. Mortality was higher in patients with FIB-4 ≥1.76 vs. FIB-4 <1.76 (26 vs. 5%, P  < 0.001) and DD ≥2000 ng/ml vs. DD <2000 ng/ml (38 vs. 16%, P  < 0.001). Using FIB-4 as a screening test (cutoff = 1.76, 90% sensitivity) followed by DD (cutoff = 2000 ng/ml; 90% specificity) identified a subgroup with higher mortality when compared with FIB-4 alone (48 vs. 26%, P  < 0.001), missing the identification of only 2% of deaths.

Conclusion: Sequential use of FIB-4 and DD represents a comprehensive strategy to identify high-risk COVID-19 patients at hospital admission, potentially minimizing unnecessary DD tests in those deemed low-risk by FIB-4.