Prognostic value of the uric acid-to-albumin ratio, prognostic nutritional index, and systemic inflammation response index in patients monitored in a pulmonary intensive care unit due to acute respiratory failure

Aims: This study aimed to evaluate the prognostic value of the uric acid-to-albumin ratio (UAR), systemic inflammation response index (SIRI), and prognostic nutritional index (PNI) in patients admitted to a pulmonary intensive care unit (ICU) due to acute respiratory failure (ARF). Methods: This retrospective observational study included 175 patients admitted to the pulmonary ICU with ARF. UAR, SIRI, and PNI were calculated from admission laboratory values. The primary outcome was 28-day clinical prognosis (good vs. poor), and the secondary outcome was 28-day all-cause mortality. Receiver operating characteristic (ROC) curve analysis and multivariable logistic regression were used to assess discriminative and independent predictive performance. Results: Of 175 patients, 99 had poor prognosis and 60 died within 28 days. Patients with poor prognosis had significantly lower PNI (36.4 vs. 38.5; p=0,021) and higher SIRI (7.61 vs. 5.15; p=0.014), while UAR did not differ significantly between groups (p=0.233). ROC analysis demonstrated modest discriminative ability for poor prognosis for both PNI (AUC=0,602; p=0.021) and SIRI (AUC=0.609; p=0.014). In the adjusted multivariable model, lower PNI showed a borderline association with poor prognosis (OR=0.953; 95% CI 0.904-1.005; p=0.080). No evaluated biomarker demonstrated significant discriminative ability for 28-day mortality. Conclusion: Impaired immunonutritional status, as reflected by a low PNI, was associated with poor 28-day prognosis and showed a borderline association after adjustment. PNI and SIRI demonstrated only modest prognostic performance and should be considered supportive rather than standalone prognostic markers. Further prospective multicenter studies are warranted.