To investigate the changes of serum sphingosine-1-phosphate (S1P) and wingless type MMTV integration site family 5a (Wnt5a) in patients with sepsis complicating acute respiratory distress syndrome (ARDS) at different disease severity and their relationships with short-term prognosis.

A total of 162 patients with sepsis complicating ARDS who were admitted to Linyi Central Hospital from March 2020 to December 2022 were selected. According to the severity of ARDS, the patients were divided into a mild ARDS group (56 cases), a moderate ARDS group (66 cases) and a severe ARDS group (40 cases). Serum S1P and Wnt5a levels were compared among these three groups. Patients were further divided into a survival group (92 cases) and a death group (70 cases) according to the prognosis after 28 days of treatment. Serum S1P and Wnt5a levels were compared between the two groups. A multivariate logistic regression model was used to analyze the influencing factors of short-term prognosis in patients with sepsis complicating ARDS. The predictive value of serum S1P and Wnt5a in the short-term prognosis of patients with sepsis complicating ARDS was analyzed by a receiver operating characteristic (ROC) curve.

The serum S1P and Wnt5a levels in the mild ARDS group, moderate ARDS group and severe ARDS group were compared, and the differences were statistically significant (F = 223.888, 63.613; both P < 0.001). Compared with the mild ARDS group, the serum S1P level was lower and the serum Wnt5a level was higher in the moderate ARDS group and severe ARDS group (all P < 0.05). Compared with the moderate ARDS group, the serum S1P level was lower and the serum Wnt5a level was higher in the severe ARDS group (both P < 0.05). The serum S1P level was lower and the serum Wnt5a level was higher in the death group than in the survival group (t = 7.380, 6.485; both P < 0.05). The age, proportion of sepsis shock, proportion of ICU residence ≥ 10 d, proportion of mechanical ventilation ≥ 3 d, acute physiology and chronic health evaluation (APACHE) Ⅱ, lactic acid level and sequential organ failure assessment (SOFA) score in the death group were higher than those in the survival group, while the proportion of vasoactive drugs and oxygenation index in the death group were lower than those in the survival group (all P < 0.05). The multivariate logistic regression model showed that the septic shock, age, serum Wnt5a level, lactic acid level, APACHEⅡ score and SOFA score were risk factors for the 28-d death of patients with sepsis complicating ARDS, while the serum S1P and oxygenation index were protective factors (all P < 0.05). ROC curve analysis showed that the area under the curve (AUC) of serum S1P and Wnt5a alone to predict death was 0.803 [95% confidence interval (CI) (0.734, 0.861), P < 0.001] and 0.758 [95%CI (0.684, 0.822), P < 0.001] respectively, and the AUC of serum S1P combined with Wnt5a to predict death was 0.866 [95%CI (0.804, 0.914), P < 0.001]. The AUC of the combined detection was greater than that of the single detection (Z = 2.405, 3.309; both P < 0.001).

The aggravation of sepsis complicated with ARDS is related to the decrease of serum S1P level and the increase of Wnt5a level, and the combined detection of the two has a high predictive effect on short-term prognosis.