Absolute lymphocyte count is a prognostic marker in Covid-19: A retrospective cohort review

Prognostic factors are needed to aid clinicians in managing Covid-19, a respiratory illness. Lymphocytopenia has emerged as a simply obtained laboratory value that may correlate with prognosis.

In this article, we perform a retrospective cohort review study on patients admitted to one academic hospital for Covid-19 illness. We analyzed basic demographic, clinical, and laboratory data to understand the relationship between lymphocytopenia at the time of hospital admission and clinical outcomes.

We discovered that lymphocyte count is lower (P = .01) and lymphocytopenia more frequent by an odds ratio of 3.40 (95% CI: 1.06-10.96; P = .04) in patients admitted to the Intensive Care Unit (ICU), a marker of disease severity, relative to those who were not. We additionally find that patients with lymphocytopenia were more likely to develop an acute kidney injury (AKI), a marker of organ failure, during admission by an odds ratio of 4.29 (95% CI: 1.35-13.57; P = .01).

This evidence supports the hypothesis that lymphocytopenia can be an early, useful, and easily obtained, prognostic factor in determining the clinical course and disease severity of a patient admitted to the hospital for Covid-19.