Predictive Value of SAPS II for 28-Day All-Cause Mortality in AECOPD Patients Admitted to the ICU

Background: The Simplified Acute Physiology Score II (SAPS II), which incorporates 12 physiological variables along with age, admission type and chronic health conditions, is widely used for assessing illness severity and predicting mortality risk in critically ill patients. However, its prognostic value in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) remains unclear. Methods: A total of 1087 eligible AECOPD patients admitted to intensive care unit (ICU) were included from the Medical Information Mart for Intensive Care IV database. The clinical characteristics and 28-day all-cause mortality of these patients were collected. Results: SAPS II was significantly higher in non-survivors than in survivors among the AECOPD patients admitted to ICU. For predicting 28-day all-cause mortality, SAPS II showed superior discriminative ability compared to the scores of Sequential Organ Failure Assessment, Oxford Acute Severity of Illness Score, and Logistic Organ Dysfunction System. The combination of SAPS II with these scoring systems did not significantly enhance the predictive value. Kaplan-Meier survival analysis identified SAPS II ≥ 37 as a significant cut-off value, with patients scoring above this threshold showing a significantly decreased 28-day cumulative survival rate. Cox regression confirmed SAPS II ≥ 37 as an independent mortality predictor. Restricted cubic spline analysis revealed a linear increase in 28-day all-cause mortality risk with elevated SAPS II. Subgroup analysis revealed that the association between SAPS II and mortality risk remained consistent across the most subgroups except for coronary heart disease. Conclusion: Our findings demonstrate that SAPS II is a significant predictor of 28-day all-cause mortality in AECOPD patients admitted to the ICU, with a score ≥ 37 serving as a robust indicator of poor clinical prognosis. Keywords: chronic obstructive pulmonary disease, acute exacerbation, mortality, SAPS II, intensive care unit