Effectiveness of copeptin protein in detecting pulmonary hypertension in patients with idiopaticpulmonary fibrosis

Purpose: The aim of this study was to compare copeptin levels in patients who have idiopathic pulmonary fibrosis with the control group and to evaluate the effectiveness of copeptin levels in predicting pulmonary hypertension in idiopathic pulmonary fibrosis (IPF). Methods: Between June and September 2021, 30 IPF cases and 30 healthy volunteers who applied to Bursa Uludag University Chest Diseases and Cardiology outpatient clinics for standart follow-up were included in the study. For all cases, we performed ECHO, copeptin levels, DLCO, and 6MWT. Results: The mean age of the IPF patients was 69.93 ± 7.44 years, 73.3% of them were male. Compared with the control group, the mean age of the IPF group was statistically higher than the control group (p = 0.003). The history of smoking was 38.61 ± 20.99 pack-year for IPF cases and 43 ± 24.52 pack-year for the control group. There was no statistical significance of smoking history between groups (p>0,05). 6MWD was 276,95 ± 126,64 meters in IPF cases and 402,5 ± 137,89 meters in the control group. 6MWD of IPF patients was statistically significantly shorter than the control group (p=0,030). The mean GAP index of the IPF cases was 3.97 ± 1.54 and it was Stage 2 according to the GAP index. In the IPF group, the mean pulmonary artery pressure was 40.63 ± 27.08 mmHg with 23 cases (76%) having right-sided loading findings. In the control group, the mean pulmonary artery pressure was 25.5 ± 7.59 with 2 cases (6.7%) having right-sided loading findings. Compared to the control group, IPF cases had statsitically higher pulmonary artery pressures and right-sided loading findings (p<0.001). In 9 (30%) patients of the IPF group systolic PAB measured >40 mmHg while only xvii one (3.3%) patient had systolic PAB >40 mmHg in the control group. Compared to the control group, the IPF group had statistically more cases with higher PAB >40 mmHg (p<0.001). The median (min – max) copeptin value was 293.4 pmol/L (148 – 854 pmol/L) in IPF cases and 194.4 pmol/L (21.3 – 349.5 pmol/L) in the control group. Pulmonary hypertension and copeptin levels were significantly higher in the IPF group compared to the control group (p<0.001). When PAP <40 mmHg was compared with those with PAP>40 mmHg in IPF cases, copeptin level was statistically significantly higher in cases with PAP>40 mmHg (p<0.001). There was a statistically significant negative correlation between copeptin level and FVC (%) and 6MWD, and a significantly positive correlation between copeptin and PAB value (r = 0.543, p = 0.002). It was determined that the copeptin level could ideally detect pulmonary hypertension due to IPF with a sensitivity of 80% and a specificity of 66.7% at the cut-off point of 226.71 pmol/L. (AUC = 0,813 [%95 GA: 0.709 – 0.918], p<0.001). Conclusions: Copeptin level in IPF cases is significantly higher than in the control group. Copeptin levels are a valuable predictive parameter in demonstrating pulmonary hypertension in patients with IPF, and it can be used in clinical practice in the future. Key words: Copeptin, Idiopathic Pulmonary Fibrosis, Pulmonary fibrosis