Prognostic properties of hypoalbuminemia in COVID-19 patients: A systematic review and diagnostic meta-analysis

Background: Coronavirus disease 2019 (COVID-19) elicits robust inflammatory reaction that may result in a declining albumin serum level. This meta-analysis aimed to evaluate the prognostic properties of hypoalbuminemia for poor prognosis and factors that may influence the relationship.

Method: A systematic literature search of PubMed was conducted from inception to April 22, 2021. The main exposure was albumin level below normal range-defined by the included studies. The outcome of interest was composite poor outcome that comprises of mortality, severity, and the requirement of mechanical ventilation or intensive care unit.

Results: There were 6200 patients from 19 studies. Meta-analysis showed that hypoalbuminemia was associated with composite poor outcome (OR 6.97 (95% CI 4.20-11.55), p < 0.001; I² = 91.3%, p < 0.001). Meta-regression analysis showed that age (p = 0.44), gender (p = 0.76), HT (p = 0.97), DM (p = 0.40), CKD (p = 0.65), liver disease (p = 0.72), and malignancy (p = 0.84) did not affect the association. Subgroup analysis showed that hypoalbuminemia increased mortality (OR 6.26 (95% CI 3.26-12.04), p < 0.001; I² = 69.6%, p < 0.01) and severity of the disease (OR 7.32 (95%CI 3.94-13.59), p < 0.001; I² = 92.5%, p < 0.01). Pooled diagnostic analysis of hypoalbuminemia yielded a sensitivity of 0.63 (95% CI 0.52-0.72), specificity of 0.81 (95% CI 0.73-0.87), and AUC of 0.77. The probability of poor outcome was 70% in patients with hypoalbuminemia and 24% in patients with normal albumin level.

Conclusion: Hypoalbuminemia was associated with poor prognosis in COVID-19 patients.