Lymphocyte blood levels that remain low can predict the death of patients with COVID-19

Abstract

The outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been rapidly spreading on a global scale and poses a great threat to human health. However, efficient indicators for disease severity have not been fully investigated. Here, we aim to investigate whether dynamic changes of lymphocyte counts can predict the deterioration of patients with COVID-19. We collected data from 2923 patients with laboratory-confirmed COVID-19. Patients were then screened, and we focused on 145 severe cases and 60 critical cases (29 recovered cases, 31 deaths). The length of hospitalization was divided into five time points, namely admission, 25%, 50%, 75% and discharge or death, according to the principle of interquartile distance. A series of laboratory findings and clinical data were collected and analyzed during hospitalization. The results showed that there were differences in levels of leukocytes, neutrophils and lymphocytes at almost every time point in the severe cases and 60 critical cases (29 recovered cases, 31 deaths). Further analysis showed that 70.2% of the COVID-19 cases had low circulating lymphocyte count, of which 64.1% were severe cases and 85.0% were critical cases (75.9% recovered cases and 93.5% died). Moreover, the lymphocyte count in dead cases was significantly lower than that of critical cases who recovered, at almost every time point in the critical groups. We also divided critical patients into group A (<1.1 × 10 9 /L) and group B (>1.1 × 10 9 /L) according to number of lymphocytes. Through survival analysis, we found that there was no significant difference in survival between group A and group B at admission ( P = .3065). However, the survival rate according to lymphocyte levels in group A was significantly lower than that of group B at 25% hospital stay (on average day 6.5), 50% and 75% time points ( P < .001). Lymphocyte counts that remain lower after the first week following symptom onset are highly predictive of in-hospital death of adults with COVID-19. This predictor may help clinicians identify patients with a poor prognosis and may be useful for guiding clinical decision-making at an early stage.

Evaluation of individual and combined NLR, LMR and CLR ratio for prognosis disease severity and outcomes in patients with COVID-19

“…The study by Zhang H.J. et al [28] showed that reduced absolute counts of lymphocyte blood levels that remain low can predict the death of patients with COVID-19. Belaid B. et al [19] hypothesized that the lymphopenia is a direct consequence of the substantial cell migration to the site of infection where the immune response is initiated.…”

Relative Importance of Various Inflammatory Markers and Their Critical Thresholds for COVID-19 Mortality

“…Several meta-analyses 2,4,5,16,17 and individual studies 18,19 have concluded that elevated levels of inflammatory markers are associated with severity and mortality in COVID-19 cases. This anyway is obvious because the elevated (low of ALC) levels of these markers indicate greater tissue damage that leads to deterioration of the condition of the patient.…”

“…Their report suggests that, on average, nearly 90% of severe patients had elevated LDH against only nearly 32% in non-severe patients. In a study of 923 patients in China, Zhang et al 19 concluded that ALC levels remaining low after the first week following symptoms onset are highly predictive of inhospital death.…”

“…Use of the term 'predictivity' by some authors 18,19,21 seems misplaced because the studies were based on records where deaths already occurred with several factors playing their role, and not prospective studies to find the mortality at different levels of the markers.…”

Mallampati Score Is an Independent Predictor of Active Oxygen Therapy in Patients with COVID-19

“…In recent months, the predictors of worse outcomes, such as age and the presence of severe chronic comorbidities, including cardiovascular and pulmonary diseases, were defined [ 3 , 4 , 5 , 6 ]. Biomarkers, such as neutrophile-to-lymphocyte ratio and interleukin-6, were established as independent predictors of COVID-19 worsening, although their evaluation was not possible until the blood sample was taken [ 7 , 8 ].…”