Absolute Lymphocytes, Ferritin, C-Reactive Protein, and Lactate Dehydrogenase Predict Early Invasive Ventilation in Patients With COVID-19

Salvador Payán-Pernía, MD; Lucía Gómez Pérez, MD; Ángel F. Remacha Sevilla, MD, PhD; Jordi Sierra Gil, MD, PhD; Silvana Novelli Canales, MD, PhD

Disclosures

Lab Med. 2021;52(2):141-145. 

In This Article

Abstract and Introduction

Abstract

Objective: Early detection of patients with COVID-19 who will need mechanical invasive ventilation (MIV) may aid in delivering proper care and optimizing the use of limited resources.

Methods: In this single-center retrospective observational study, we aimed to identify simple laboratory parameters that in combination with ferritin (a surrogate marker of severe inflammation) may help predict early (first 48 hours) MIV. A total of 160 patients with COVID-19 in whom serum ferritin, absolute lymphocyte count (ALC), platelet count, C-reactive protein (CRP), and lactate dehydrogenase (LDH) had been analyzed at admission were included.

Results: We found that ferritin, LDH, ALC, and CRP predicted with 88% accuracy the probability of early MIV. Results indicated that LDH showed the greater area under the curve (AUC), with a value of 89.1%. Using the AUC, we established cutoff values for clinical application. Finally, we developed a classification tree based on LDH for its clinical use.

Conclusion: Ferritin, LDH, ALC, and CRP predict with 88% accuracy the probability of early MIV.

Introduction

As of October 4, 2020, the World Health Organization reported a total of 34,804,348 confirmed COVID-19 cases of infection globally, including 1,030,738 deaths.[1] The most common clinical features at the onset of the illness caused by SARS-CoV-2 are fever, fatigue, and dry cough. Patients with severe illness may develop dyspnea and hypoxemia within 1 week after onset of the disease, which may quickly progress to acute respiratory distress syndrome (ARDS) or end-organ failure.[2]

Since the outbreak in December 2019, the sudden increase in COVID-19 cases of infection is putting high pressure on healthcare services worldwide, with particular significance in intensive care units (ICU). Reported rates of ICU admission represent up to one-quarter of hospitalized patients, but rates vary among countries.[3] These differences may relate to the availability of ICU beds, variations in practice and admission criteria, and differences in predisposing factors and testing availability.

Researchers have learned that ARDS is the most common complication for ICU admission; in a series of 1300 patients admitted to the ICU in the Lombardy region of Italy, 88% required endotracheal intubation and mechanical ventilation.[3] Similarly, two-thirds of patients with COVID-19 who required critical care in the United Kingdom had mechanical ventilation within 24 hours of admission.[4] Therefore, early detection of patients who will need mechanical invasive ventilation (MIV) may aid in delivering proper care and optimizing the use of limited resources, and this is of particular interest in lower- and middle-income countries.

Several laboratory parameters have been associated with worse outcomes in patients with COVID-19: elevated liver enzymes, ferritin, IL-6, lactate dehydrogenase (LDH), C-reactive protein (CRP), D-dimer, prothrombin time, troponin, and creatine phosphokinase, along with lymphopenia and acute kidney injury.[5–7]

Hyperferritinemia has been linked to macrophage activation syndrome (MAS), which is present in serious inflammatory disease;[8] MAS is quite possibly the origin of the severest clinical manifestations of SARS-CoV-2 infection.[9]

In this setting, we aimed to identify simple laboratory parameters that in combination with ferritin may help to predict early (first 48 hours) MIV by orotracheal intubation.

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