Follow-up parameters and their progression in patients with UIP (usual interstitial pneumonia)pattern on throx computed tomography and in whom antifibrotic treatment was iniated

Objective:Idiopathic pulmonary fibrosis (IPF) is a chronic, fibrosing interstitial pneumonia of unknown etiology characterized by the radiological and histopathological features of usual interstitial pneumonia (UIP). IPF is associated with significant morbidity and mortality, with outcomes often worse than many malignancies. This study aimed to identify the follow-up parameters used in patients with a UIP pattern on high-resolution computed tomography (HRCT), to assess the relationship between these parameters and disease progression, and to determine progression rates. Additionally, we aimed to highlight the importance of early diagnosis in these patients, its impact on progression, and to raise awareness regarding its recognition in mortality statistics. Materials and Methods:We retrospectively reviewed medical records from the Hospital Information Management System (HIMS) database for patients admitted to the Pulmonology Department of Bolu Abant İzzet Baysal University Training and Research Hospital between January 1, 2019, and January 1, 2024. Patients with a UIP pattern on thoracic HRCT, diagnosed with interstitial lung disease, and initiated on antifibrotic therapy were included. Data collected included demographic characteristics, presenting symptoms, physical examination findings, comorbidities, smoking history, occupational and environmental exposures. Follow-up data such as pulmonary function tests (PFTs), systemic immune-inflammation index (SII), six-minute walk test (6MWT), and laboratory results were also recorded. Survival times and quality of life after diagnosis were assessed, and mortality data were obtained from the national Death Notification System (DNS). Results:A total of 40 patients with a UIP pattern on HRCT who were initiated on antifibrotic therapy were included. The mean age was 68.2 ± 7.19 years, and 82.5% (n=33) were male; 40% were manual laborers. At least one comorbidity was present in 85.29% of patients, and 45% had a smoking history of ≥30 pack-years. The most frequent symptoms were dyspnea (90%), cough (87.5%), sputum production (57.5%), and chest pain (17.5%). On auscultation, crackles were detected in 87.5%, rhonchi in 7.5%, while 5% had normal findings. Twenty-four patients received pirfenidone and sixteen received nintedanib; there was no statistically significant difference in forced vital capacity (FVC) changes between the two antifibrotic agents (p>0.05). Mortality was observed in 25% of pirfenidone users and 12.5% of nintedanib users. Antifibrotic-related adverse events were reported in 67.5% of patients, the most common being pruritus (28.57%), nausea/vomiting (17.86%), diarrhea (17.86%), rash with pruritus (14.29%), and weight loss (14.29%). Of the 40 patients, 8 died during follow-up, three of whom had concomitant malignancies. While 73.33% (n=33) had no malignancy, 15.56% (n=7) had an existing malignancy, and 11.11% (n=5) developed lung cancer within five years. Neutrophil counts increased in 30 patients but decreased in 10; no significant difference was observed in lymphocyte or platelet counts, whereas the change in neutrophil counts was statistically significant (p<0.001). The median SII index increased from 532.61 at baseline to 794.32 over five years (p<0.05). Mean FVC decline was -20.71% in deceased patients versus -16.87% in survivors. The mean five-year DLCO decline was -21.51%. Among deceased patients, the six-minute walk distance decreased by -28.36%, and 35.71% of those with a >5-point decrease in SpO₂ during the 6MWT experienced mortality. Conclusion:The UIP pattern is the most common radiological finding in IPF and is associated with progressive lung function decline and high mortality. Follow-up parameters including PFT, DLCO, SpO₂, 6MWT, imaging, and laboratory values provide prognostic information. Further large-scale studies are warranted to refine diagnostic, therapeutic, and prognostic approaches in this patient population. Keywords:UIP pattern, prognosis, mortality, follow-up parameters