Initial complete blood count score and predicting disease progression in COVID-19 patients

Coronavirus has caused a pandemic since it was first detected in Wuhan in December 2019. The mortality rate is high in moderate and severe cases. Our study aimed to screen the CBC parameters as a useful predictive factor for COVID-19 resulting in critical illness.

A total of 285 patients with positive PCR results were analyzed. The median age was 55 (24-90), and 64.2% of patients were male. Sixty-eight percent of cases were hospitalized with moderate, 32% with severe disease at initial admission.

We found that lymphocyte count <620/mcl, neutrophil-to-lymphocyte ratio (NLR) >6, and platelet to lymphocyte ratio (PLR) >350 were predictive of the outcome. We scored our cohort 0-3 for these three parameters. Patients with a score of 2-3 were more likely to have progressive disease, anti-cytokine treatment, intensive care admission, intubation, and death, compared to patients with a score of 0-1. Additionally, they tended to be hospitalized for longer (median 11.5 days, mean 15.6), compared to those with a score 0 or 1 (median 9 days, mean 11.3). Twenty-eight of 38 cases with scores of 2-3 were discharged (73.6%), whereas the rate was 89% for patients with a score of 0-1 (P=0.009).

Based on the absolute lymphocyte count (<620/mcl, NLR >6, PLR >350), our three-parameter score was able to predict disease progression, and the likelihood of anti-cytokine treatment, intubation, and death. We think that COVID-19 patients presenting with moderate to severe pneumonia, and having scores of 2 or 3 on our scale, should be closely monitored and robustly supported.