Relationship of prognostic nutritional index with clinical outcomes and survival in idiopathic pulmonary fibrosis

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive lung disease. Nutritional indices have been reported as significant prognostic factors in IPF. This study aimed to evaluate the relationship between the prognostic nutritional index (PNI) and clinical findings, functional parameters, prognosis, and mortality in patients with IPF followed in our clinic. METHODS: This retrospective study reviewed the medical records of patients diagnosed with IPF between 2014 and 2021. The GAP (Gender, Age, Physiology) score, pulmonary function tests, and laboratory results were recorded at the time of diagnosis and at the initiation of antifibrotic treatment. PNI was calculated using serum albumin and lymphocyte counts according to a previously defined formula. Patients were followed from the start of antifibrotic therapy to their final visit within the sixth month. All baseline data were reassessed at the six-month follow-up. Survival time was defined as the period from the initiation of follow-up to the date of death. For patients who were still alive, survival was calculated up to the end of the final data collection, which concluded in December 2024. RESULTS: A total of 120 patients (86 males; mean age: 69.2 ± 8.5 years) diagnosed with IPF were included. The most common symptoms were dyspnea (87.5%) and cough (82.5%). Forty-eight patients died during the study period. The modified Medical Research Council (mMRC) dyspnea scores and GAP scores were significantly lower in survivors (p = 0.016 and p < 0.001, respectively), whereas PNI levels were significantly higher in this group (p = 0.004). Baseline PNI levels showed weak negative correlations with both the mMRC score (r = - 0.308, p < 0.001) and the GAP score (r = - 0.358, p < 0.001). PNI levels at baseline and at 6 months were significantly higher in patients with stable parenchymal findings than in those with progressive fibrosis (p < 0.001). CONCLUSIONS: These findings suggest that PNI, which reflects both nutritional and inflammatory status, may serve as a useful prognostic marker for predicting disease progression and mortality in patients with IPF.