key: cord-0873402-piwvcr7q
authors: Magoon, Rohan; Jain, Ankur
title: Haematological inflammatory prognostication in COVID-19: Points to ponder!
date: 2020-12-29
journal: Am J Emerg Med
DOI: 10.1016/j.ajem.2020.12.070
sha: 67600286cb948c3fd705f86839a3c7a73ddc3f19
doc_id: 873402
cord_uid: piwvcr7q

nan

Haematological inflammatory prognostication in COVID-19: Points to ponder!

We read with great interest the research reports of haematological inflammatory prognostication in COVID-19 featured recently in the Journal [1, 2] . While the Seyit et al. elucidation of elevated haematological ratios such as neutrophil-to-lymphocyte ratio (NLR) and platelet-tolymphocyte ratio (PLR) in COVID-19 subset [1] and the Moradi et al. depiction of COVID-19 mortality predictive value of NLR are promising [2] , additional points mandate elaboration to render a more comprehensive purview of this parsimonious prognostication.

(i) The lack of comparative data on the platelet counts in Moradi et al. study merits attention, particularly when a prognostic potential has been attributed to PLR in a COVID-19 setting studied by Qu et al. [3] . This becomes all the more relevant in the light of Fois and colleagues description of an independent COVID-19 mortality predictive value of a combined plateletleukocytic index or the systemic immune-inflammation index (SII = neutrophil × platelet-to-lymphocyte ratio) in their retrospective evaluation of 119 COVID-19 patients [4] . Furthermore, SII emerged as the sole COVID-19 prognostic haematological parameter (Hazard ratio:1.0001; 95% confidence interval:1.0000 to 1.0001; p value: 0.029) subsequent to a multivariate Cox regression analysis in their evaluation of the mortality predictive potential of indices like SII, systemic inflammation response index (SIRI = neutrophil × monocyte-to-lymphocyte ratio) and the aggregate index of systemic inflammation (AISI = neutrophil × platelet×monocyte-to-lymphocyte ratio) alongside the conventionally described ratios like NLR, PLR and monocyte-to-lymphocyte ratio (MLR) [4] . (ii) While the Moradi et al. retrospective study classifies the included 219 COVID-19 patients premised on the peripheral oxygen saturation values at admission (SpO 2 ≤ 90% and >90%), it fails to account for the subsequent oxygenation parameters during the course of the disease, particularly with 63 participants requiring intensive care unit (ICU) admission in their study [2] . The importance of the respiratory physiological status assessment is highlighted in the Qu et al. finding of a severe pneumonia in COVID-19 patients with increased PLR [3] . In this context, Fois et al. also describe substantially worse partial pressure of arterial oxygen/fractional inspired oxygen concentration (PaO 2 /FiO 2 ) ratios in COVID-19 patients with an elevated SII [4] . (iii) As an extension of the same, Fois et al. propose a potential ability of SII to reflect the pulmonary consequences of COVID-19 independent of the comorbidity status supported by the insignificant differences in the respective Charlson comorbidity index (CCI) between the groups with or without SII greater than the cut-off value of 1835 in their study in background of significantly dismal PaO 2 /FiO 2 ratios in the high SII group as discussed above [4] . Herein, the incorporation of a composite comorbidity index like CCI alongside PaO 2 /FiO 2 ratios and/or chest computed tomography (CT) severity scores in Moradi et al. study could have assisted the authors in a much required exploration of the intriguing links between the haematological prognostic markers and the pulmonary inflammatory sequel in COVID-19 patients [3] [4] [5] . (iv) Lastly, in addition to the patient-related factors and hospital admission-parameters which mandate adjustment for a NLR outcome predictive assessment in Moradi et al. study, various other overlooked factors over the stipulated disease course like the level of care and the end-organ failure indicators, etc. could have possibly confounded a sound predictive potential evaluation, necessitating a careful interpretation of the results [6, 7] .

Amidst the ever growing interest in haematological risk prediction across diverse clinical settings predisposed to inflammation [8, 9] , this initial retrospective literature also endorses a strong case for haematological inflammatory prognostication in COVID-19. Nevertheless, pragmatic prospective evaluation should closely back up the initial encouraging results in order to assist in an early, parsimonious and comprehensive risk-stratification of COVID-19 cohort which could further enable the optimal implementation of risk-based individualised management.

Rohan Magoon: Writing -original draft. Ankur Jain: Conceptualization, Writing -review & editing.

We do not have any conflict of interest, any commercial or financial interest in this material & agree to abide by the rules of your journal regarding publication of this article.

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