Association between lactate dehydrogenase-to-albumin ratio and oxygen therapy requirement in hospitalized patients with COVID-19: A retrospective observational study

Although pulse oximetry (SpO2) is useful for real-time monitoring of oxygen saturation, it may not predict which patients will subsequently develop hypoxemia and require oxygen therapy. Laboratory biomarkers collected at admission may therefore facilitate earlier risk stratification and guide clinical decision-making. This study aimed to evaluate the association between the lactate dehydrogenase-to-albumin ratio (LAR) and oxygen therapy requirement in hospitalized patients with COVID-19. This retrospective study included hospitalized patients with COVID-19 admitted to the ICU of the Cancer Center of Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, between February and March 2020. Patients were categorized into a non-oxygen therapy group (n = 40) and a group requiring oxygen therapy (n = 21) according to the requirement for supplemental oxygen therapy (SpO2 < 93%). Univariate and multivariate logistic regression analyses were performed to identify factors associated with oxygen therapy requirement. Receiver operating characteristic (ROC) curves were used to assess the predictive performance of the identified factors. Sixty-one hospitalized patients with COVID-19 (mean age 63.18 ± 11.01 years; 22 males [36.07%]) were included, among whom 21 required oxygen therapy. Multivariable logistic regression analysis showed that the lactate dehydrogenase-to-albumin ratio (LAR; OR = 2.06, 95% CI: 1.00-4.21, P = .049) was independently associated with oxygen therapy requirement. ROC analysis demonstrated that LAR had an area under the curve (AUC) of 0.762 with 81.0% sensitivity and 72.5% specificity at an optimal cutoff value of 5.240. A combined model incorporating LAR, lymphocyte count, cough, d-dimer, bilateral lung involvement, chest tightness, and shortness of breath achieved an AUC of 0.818 with 76.2% sensitivity and 80.0% specificity. LAR was independently associated with oxygen therapy requirement in hospitalized patients with COVID-19 and may help clinicians identify patients at higher risk of requiring oxygen therapy, thereby supporting early triage and optimal allocation of medical resources.