The Correlation between Absolute Lymphocyte Counts and Clinical Outcomes in COVID-19 Patients

Introduction

The Severe acute respiratory syndrome 2, or Sars-Cov-2, more commonly called coronavirus (COVID-19) is a global pandemic of epic proportions. The global spread occurred as many patients carrying the virus were unaware that asymptomatic patients can still spread the infection. Common manifestations of COVID-19 include: fever, chills, fatigue, nausea, vomiting, radiologic evidence of bilateral infiltrates, acute respiratory distress syndrome and multi-organ failure leading to death. Treatment options for the coronavirus are rapidly changing, because there is a lack of evidence. There is currently very limited data regarding lab prognosis for patients with the novel coronavirus. Lab prognosis is beneficial to physicians making life decisions without guideline recommendations to support their decisions. A decrease in absolute lymphocyte counts, ALC, is a common manifestation in many viral diseases as well as in Covid-19 infection. At later disease stage, more profound hematological changes are evidenced, particularly a significant reduction in the lymphocytes number. This finding was more evident in those who suffered death compared to those who survived as reported in a study in China. Our study investigates the correlation between ALC and clinical outcomes in African American population.

Methods

In this article, we performed a retrospective cohort study on 92 patients admitted to a community hospital for Covid‐19. The patient population was 80% over the age of 61, 88% African Americans, 61% male and 32% obese. We split the 92 patients into four groups based on age in years: Group 1 was 21-40, Group 2 was 41-60, Group 3 was 61-80 and Group 4 was 81-100. The electronic medical record system was used to collect baseline demographics and laboratory data for analysis. Additionally, we evaluated baseline ALC at the time of hospital admission as well as the subsequent ALC to asses the correlation with clinical outcomes. A Pearson correlation coefficient was used to determine correlation between improving ALC and better clinical outcomes.

Results

For group 1, we did not have enough patients to make an assessment for correlation. The two largest groups 41-60 and 61-80 years showed the biggest improvement in average ALC from baseline 1.1, 1.2 respectively to end result 1.64, 1.5 and showed a significant correlation with clinical outcomes as, a majority, 65% of these patients was discharged. A total of 24% of patients in group 4 expired and can be explained by increased d-dimer levels greater than 4 mg/dL and increased PT possibly leading to disseminated intravascular coagulation. Overall, 64% of our patient population was discharged and 36% expired.

Conclusion

This study showed correlation between clinical outcomes and ALC. Recording of ALC had clinical values, with decreasing ALC noted in severe /fatal disease and improvements noted in patients with favorable outcomes leading to safe hospital discharge.