Decrease in Hemoglobin Level Predicts Increased Risk for Severe Respiratory Failure in COVID-19 Patients with Pneumonia

Background: In December 2019, the coronavirus disease (COVID-19), caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), emerged in Wuhan, China, and has since spread throughout the world. This study aimed to investigate the association between the change in laboratory markers during the three days after pneumonia diagnosis and severe respiratory failure in COVID-19 patients.

Methods: Data of 23 COVID-19 patients with pneumonia, admitted to the Kumamoto City Hospital between February and April 2020 were retrospectively analyzed.

Results: Among the 23 patients, eight patients received mechanical ventilation (MV) (MV group), and the remaining 15 comprised the non-MV group. The levels of hemoglobin (Hb) and albumin (Alb) decreased in the MV group during the three days after pneumonia diagnosis more than in the non-MV group (median Hb: 1.40 vs. -0.10 g/dL, P = 0.015; median Alb: 0.85 vs. -0.30 g/dL, P = 0.020). Univariate logistic regression analysis showed that the decrease in Hb was associated with receiving MV care (odds ratio: 0.313, 95% confidence interval: 0.100-0.976, P = 0.045). Receiver operating characteristic curve analyses showed that the optimal cut-off value for the decrease in Hb level was -1.25 g/dL, with sensitivity and specificity values of 0.867 and 0.750, respectively.

Conclusions: The decrease in Hb level during the short period after pneumonia diagnosis might be a predictor of worsening pneumonia in COVID-19 patients.