Hypoalbuminemia on admission in COVID-19 infection: An early predictor of mortality and adverse events. A retrospective observational study.

Objectives: Hypoalbuminemia is a negative acute phase reactant which has been associated with inflammatory response and poor outcome in infectious diseases. The aim of this study was to analyze the value of hypoalbuminemia on admission as a predictor of mortality and adverse events in COVID-19 patients.

Methods: We analyzed retrospective data from a cohort of 609 consecutive patients, with confirmed diagnosis of COVID-19, discharged from hospital (deceased or alive). Demographic characteristics, previous comorbidities, symptoms and laboratory findings on admission were collected. Comorbidities were assessed by Charlson-Age Comorbidity Index.

Results: Hypoalbuminemia on admission (<34g/L) was more frequent in nonsurvivors than survivors (65.6% vs. 38%, p<0.001) and was significantly associated with the development of sepsis, macrophage activation syndrome, acute heart failure, acute respiratory distress syndrome and acute kidney injury, regardless of Charlson-Age Comorbidity Index. Hypoalbuminemia was a predictor of mortality in multivariable Cox regression analysis (HR 1.537, 95% CI 1.050-2.250, p=0.027), independently of Charlson-Age Index, gender, lymphocyte count <800/μL, creatinine, high-sensitivity C- reactive protein >8mg/L, lactate dehydrogenase >250U/L, bilateral infiltration on chest X-ray and q-SOFA ≥2.

Conclusions: Hypoalbuminemia was an early predictor of in-hospital mortality in COVID-19, regardless of age, comorbidity and inflammatory markers. It also had significant association with severe adverse events, independently of Charlson-Age Comorbidity Index. Our results suggest that serum albumin determination on admission may help to identify patients with SARS-CoV-2 infection at high risk of developing potential life-threatening conditions and death.