LDH and NLR, as inflammatory markers, the independent risk factors for COVID-19 complicated with respiratory failure in elderly patients.

OBJECTIVE

Lactate dehydrogenase (LDH) is an enzyme that is responsible for the production of lactic acid, which is a necessary byproduct when the body does not have enough oxygen. LDH levels in the blood can be used as a marker to predict mortality in patients with ARDS, severe COVID-19, and cancer. To analyze the clinical characteristics of COVID-19 in the elderly and the correlation between LDH and respiratory failure in COVID-19 patients, to improve the identification and management of this type of pneumonia by clinicians.

METHODS

This was a single-center retrospective study. We performed routine laboratory tests in 105 COVID-19 patients admitted to the affiliated hospital of Qingdao University (Qingdao, China) from October 1, 2022 to February 1, 2023. The diagnosis of respiratory failure was established based on the results of blood gas analysis upon admission.

RESULTS

The median age was 79 years. Among all univariable parameters, LDH, neutrophil to lymphocyte ratio (NLR) and Prothrombin Time (PT) were significantly independent risk factors of RF in elderly COVID-19 patients. LDH (AUC=0.829) also had a maximum specificity (96.5%), with the cutoff value of 280.5.

CONCLUSION

The levels of LDH, NLR, and PT may serve as potential indicators for elderly COVID-19 patients combined with respiratory failure. LDH, NLR and PT assays can be beneficial for patients who need closer respiratory monitoring and more aggressive supportive care to prevent a negative prognosis.