potential utility of systemic immune-inflammation index: nlr, plr, and sii to detect poor prognosis of covid-19 patients from the mexican southeast

Background: since december 2019, the sars-cov-2 virus has been highly contagious and pathogenic, causing mild to severe respiratory failure. the most investigated biomarkers can help to predict disease progression and guide treatment decisions. expert clinicians suggested that the neutrophil-lymphocyte ratio (nlr) and platelet-lymphocyte ratio (plr) represent rapid, easy, widely available, and relatively inexpensive tools. objectives: we aimed to explore the nlr and plr in predicting the poor prognosis of covid-19 patients in the mexican southeast. methods: in this retrospective study, we included hospitalized adults with covid-19 from dr. juan graham casasús hospital who had survived or non-survived between june 2020 and january 2022. demographic and laboratory data were acquired from electronic medical records. we calculated nlr, plr, and sii. the continuous variables were expressed as average and were compared with the student t-test, as well as with the categorical variables. these were expressed as numbers and percentages and were compared with the χ2 test between the survivor group and the non-survivor group. the sensitivity and specificity in the prediction of death according to the cutoff values of the nlr, plr, and the sii by roc curve. p values less than 0.05 were considered significant. results: we admitted 189 patients. the average age was 61.8 ± 17.3 years, 59.8% (n = 113) were men, and 55.6% (n = 105) were non - survivors. we showed differences among survivors and non - survivors, age (65.6 vs. 56.9 p = 0.001), white blood cell count (14.1 vs. 10.2 p = 0.001), neutrophil (12.4 vs. 8.5 p = 0.002), crp (213.7 vs. 158.5 p = 0.003), il - 6 (192.3 vs. 81.0 p = 0.005), nlr (23.5 vs. 11.4 p = 0.000), plr (524.8 vs. 287.6 p = 0.010), sii (6982.0 vs. 3003.1 p = 0.004). the optimal cutoff for the nlr was 8.6 with a sensitivity of 70.4% and a specificity of 51.8 (auc 0.678, ci 95% 0.6024 - 0.7541, p < 0.0001), for the plr where it shows 252.6 with a sensitivity of a 60.0% and a specificity of 50.6 (auc 0.6096, ci 95% 0.5297 - 0.6895, p < 0.0099), for the sii that 1815 with a sensitivity of 70.4%, and a specificity of 51.8 (auc 0.6566, ci 95% 0.5788 - 0.7344, p < 0.0002). conclusions: we propose that nlr, plr, and sii should be considered an inexpensive, accessible, and effective biomarker in the management of patients with covid-19. in conclusion, the high nlr, plr, and sii were related to poor prognosis in covid-19 patients.