Low platelet counts and monocytosis were associated with reduced risk of severe COVID-19 manifestation: a single-center study from Indonesia

Introduction: Severe morbidity and mortality in COVID-19 are linked to an inflammatory ‘cytokine storm’ driven
by hyperactive macrophages and altered monocyte function. Identifying early immune predictors of severe

COVID-19 outcomes is critical for optimizing patient care and resource allocation, especially under a resource-
limited setting.

Objectives: This study aimed to investigate the relationship between monocyte and platelet levels and COVID-19
severity at a secondary hospital in East Java, Indonesia.
Patients and Methods: A single-center, cross-sectional study was conducted by utilizing electronic medical health
records from 100 patients admitted to the Siti Khodijah Muhaammadiyah Sepanjang hospital May to September

2021. Initial complete blood counts were retrieved from adult patients who tested positive for COVID-19 by real-
time quantitative reverse transcription polymerase chain reaction (qRT-PCR ). A backward-stepwise multivariate

regression model was incorporated to evaluate the association between platelet and monocyte levels with
COVID-19 severity.
Results: Despite the non-association in the bivariate analysis, thrombocytopenia significantly reduced the risk
of severe COVID-19 manifestation in the multivariate model (aPR 0.184; 95% CI: 0.047-0.722). Interestingly,
patients with monocytosis had a lower risk of the severe disease compared to those with normal monocytes both
in the bivariate and multivariate analyses (PR 0.364; 95% CI [0.157-0.841] and aPR 0.334; 95% CI [0.126-0.882],
respectively). However, there was no significant increase in severity among those presenting with low monocyte
or high platelet counts.
Conclusion: There is a unidirectional association between low platelets and high monocyte levels with severe
manifestations of COVID-19 disease. Further research is warranted to validate these findings and explore their
utility in risk stratification and clinical management of COVID-19 patients.