The U-shaped relationship between admission peripheral oxygen saturation and all-cause hospital mortality in acute exacerbation of chronic obstructive pulmonary disease: a retrospective analysis using the MIMIC III database

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Key findings

• This study investigated the U-shaped nonlinear relationship between admission oxygen saturation (SpO₂) and all-cause hospital mortality in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). The results showed that the lowest all-cause hospital mortality was observed at an SpO₂ of 89.5%. Additionally, SpO₂ was identified as an independent risk factor for predicting all-cause hospital mortality in AECOPD patients, providing valuable guidance for optimizing oxygen therapy in this population.

What is known and what is new?

• Most studies indicate that maintaining SpO₂ levels between 88–92% provides significant benefits for AECOPD patients. However, there is limited research on the relationship between SpO₂ and all-cause hospital mortality in AECOPD patients.

• This study investigated the nonlinear U-shaped relationship between SpO₂ and all-cause hospital mortality in AECOPD patients. It offers a readily available indicator for assessing the severity of AECOPD and provides evidence to guide oxygen therapy in clinical practice.

What is the implication, and what should change now?

• More prospective studies are urgently needed to explore the relationship between SpO₂ and all-cause hospital mortality in AECOPD patients, providing further evidence to improve the prognosis of these patients.