Predictive validity of the sequential organ failure assessment score for mortality in patients with acute respiratory distress syndrome in Vietnam

Abstract

Evaluating the prognosis of ARDS patients using grading systems can enhance treatment decisions. This retrospective observational study evaluated the predictive accuracy of the SOFA score, APACHE II score, SpO₂/FiO₂ ratio, and PaO₂/FiO₂ ratio for mortality in ARDS patients in Vietnam. The study included 335 adult ARDS patients admitted to a central hospital from August 2015 to August 2023. Among them, 66.9% were male, the median age was 55 years, and 61.5% died in the hospital. The SOFA (AUROC: 0.651) and APACHE II scores (AUROC: 0.693) showed poor discriminatory ability for hospital mortality. The SpO₂/FiO₂ (AUROC: 0.595) and PaO₂/FiO₂ ratios (AUROC: 0.595) also displayed poor discriminatory ability. In multivariable analyses, after adjusting for the same set of confounding variables, the APACHE II score (adjusted OR: 1.152), SpO₂/FiO₂ ratio (adjusted OR: 0.985), and PaO₂/FiO₂ ratio (adjusted OR: 0.989) were independently associated with hospital mortality. Although the SOFA score (adjusted OR: 1.132) indicated a potential association with hospital mortality, it did not reach statistical significance (p = 0.081). However, a SOFA score of ≥ 10 emerged as an independent predictor (adjusted OR: 3.398) of hospital mortality. These findings emphasize the need for further studies to develop more accurate scoring systems for predicting outcomes in ARDS patients.

Keywords: APACHE II score; Acute respiratory distress syndrome (ARDS); Berlin definition criteria; Critical care; Mechanical ventilation; Mortality; New global definition; PaO2/FiO2 ratio; SOFA score; SpO2/FiO2 ratio.

Fig. 1

Flowchart of the study design.

Fig. 2

Overall predictive performance of the SOFA and APACHE II scores for hospital mortality in ARDS patients. The SOFA score had an AUROC of 0.651 (95% CI 0.591–0.710) with a cut-off value of ≥ 9.5, a sensitivity of 60.7%, a specificity of 63.6%, and a PAUROC of < 0.001. Similarly, the APACHE II score showed an AUROC of 0.693 (95% CI 0.636–0.750) with a cut-off value of ≥ 19.5, a sensitivity of 55.4%, a specificity of 74.4%, and a PAUROC of < 0.001. However, both scoring systems exhibited poor discriminatory ability for hospital mortality. A positive correlation was observed between these scores and hospital mortality rates. APACHE II, Acute Physiology and Chronic Health Evaluation II score; ARDS, acute respiratory distress syndrome; AUROC, the area under the receiver operator characteristic curve; CI, confidence interval; SOFA, Sequential Organ Failure Assessment score.

Fig. 3

Overall predictive performance of the SpO₂/FiO₂ and PaO₂/FiO₂ ratios for hospital mortality in ARDS patients. The SpO₂/FiO₂ ratio (AUROC: 0.595 [95% CI: 0.531–0.658]; cut-off value ≥ 90.50; sensitivity: 35.3%; specificity: 79.7%; P_AUROC=0.004) and the PaO₂/FiO₂ ratio (AUROC: 0.595 [95% CI: 0.529–0.660]; cut-off value ≥ 45.40; sensitivity: 76.2%; specificity: 46.0%; P_AUROC=0.004) demonstrated poor discriminatory ability for hospital mortality. An inverse correlation was observed between these ratios and hospital mortality rates. ARDS, acute respiratory distress syndrome; AUROC, the area under the receiver operator characteristic curve; CI, confidence interval; PaO₂/FiO₂, the ratio of the arterial oxygen partial pressure to the fraction of inspiratory oxygen concentration; SpO₂/FiO₂, the ratio of peripheral oxygen saturation to the fraction of inspiratory oxygen concentration.