Statistical analysis
Mean, standard deviation, ranges, median, range, frequency, and ratio
data were calculated as descriptive statistics. The Kruskal–Wallis and
Mann–Whitney U tests were used for the analysis of numerical
independent data. Receiver operating characteristic (ROC) curves were
set up to identify the cut off value for KL6 to differentiate patients
with and without ILD, matching with the Youden method33,34, which detect sensitivity and
specificity. Estimation of the area under the ROC curve and its 95%
confidence interval, Sensitivity, specificity, positive and negative
predictive values related with the cut off value were all calculated.
All statistical analyses were applied using SPSS for Windows 15
statistical software. A value of p<0.05 was statistically
significant, a value of p<0.001 was highly statistically
significant, and a value of p>0.05 was non-statistically
significant.