Multiparametric correlation of laboratory biomarkers to multiorgan failure outcome in hospitalized COVID-19 patients: a retrospective observational study

Objective: COVID-19 is an extremely contagious illness caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), that will keep broadly circulating and evolving. Collected evidence revealed the clinical profile of COVID-19 patients as a potential predictor of their outcome. The aim of this study was to investigate the causal relationship between poor outcomes and laboratory parameters in hospitalized COVID-19 patients, in this sense observing how SARS-CoV-2 infection affects other organs. Patients and methods: We retrospectively evaluated a cohort of 133 patients, positive for SARS-CoV-2, aged between 30 to 94 years, between January 12th and April 25th, 2021. Discharge from the hospital, transferral to the ordinary ward or nursing home, intensive care unit (ICU) admission, and in-hospital mortality were recorded, along with demographic, laboratory and clinical parameters. The whole sample was summarized by median (interquartile range) for quantitative data, and absolute and relative percentage frequencies for qualitative variables. Univariable logistic regression models were performed to assess the association between all the parameters of interest and COVID-19 adverse outcomes, single (in-hospital mortality) and composite (in-hospital mortality and ICU admission). Hence, a multivariable model was fitted to identify potential independent predictors of the composite outcome. The accuracy of the model was assessed through appropriate fitting indices, such as the C-statistic and Hosmer-Lemeshow test. Moreover, to detect multicollinearity, the variance inflation factor (VIF) was used. Results: Our study sample had a median age of 72 years old (59.0-83.0). The most common comorbidities were hypertension (63.7%), cardiovascular disease (41.9%), diabetes (33.6%), and cerebrovascular disease (21.5%); while as the most common symptoms, we observed dry cough (32.5%), dyspnoea (50.8%), and fatigue (29.8%). Totally, 18 patients died during hospitalization (13.5%), 10 required ICU admission (7.5%), 78 (58.6%) were discharged from the hospital, and 27 (20.3%) were transferred to either ordinary wards or nursing homes. We disclosed an association of older age with both composite [OR 1.06, 95% CI 1.02-1.09; p=0.003] and single outcome [OR 1.10, 95% CI 1.04-1.16; p=0.001]. A higher oxygen saturation (SpO2) was associated with a better outcome [OR 0.75, 95% CI 0.60-0.93; p=0.009 and OR 0.76, 95% CI 0.61-0.95, p=0.009]. Among laboratory parameters, higher levels of neutrophils increased the risk of a poor outcome [OR 1.05, 95% CI 1.00-1.10; p=0.043]; while higher levels of lymphocytes seem associated with a better outcome [OR 0.94, 95% CI 0.88-0.99; p=0.043]. Higher levels of creatinine were associated with a higher risk of both adverse outcomes [OR 6.20, 95% CI 2.16-17.81; p<0.001 and OR 19.90, 95% CI 5.07-78.06; p<0.001, respectively]. Higher levels of sodium (Na) were associated with a higher risk of adverse events [OR 1.15, 95% CI 1.03-1.28; p=0.014 and OR 1.14, 95% CI 1.01-1.27]. Similar findings were also observed for C-reactive protein (CRP) levels [OR 1.01, 95% CI 1.00-1.02; p=0.010 and OR 1.01, 95% CI 1.00-1.02; p=0.024]. Conversely, being positive to IgM and IgG decreases the risk of adverse outcomes [IgM: OR 0.33, 95% CI 0.14-0.77; p=0.011 and OR 0.23, 95% CI 0.08-0.66; p=0.006. IgG: OR 0.30 95% CI 0.13-0.72; p=0.007 and OR 0.22 95% CI 0.07-0.66; p=0.007]. Hence, a multivariable model was fitted to identify potential independent laboratory predictors of the composite outcome, with laboratory parameters that showed an association with composite outcome. The model can be considered accurate according to LH-Test and C-statistic [p>0.83, C-stat=0.90]. Conclusions: Our findings confirm that COVID-19 is a multiorgan disease. In fact, the analysis of laboratory parameters has revealed a strong relationship between poorer outcomes and multiple organ dysfunction, particularly established by higher levels of neutrophils, creatinine, sodium, and CRP. Alongside, cerebrovascular diseases, chronic kidney disease and older age supported this finding. Of note, higher levels of SpO2, and lymphocytes, as well as positivity to IgM and IgG were associated with a lower risk of a poor outcome.