Quantitative CT analysis of honeycombing area predicts mortality in idiopathic pulmonary fibrosis with definite usual interstitial pneumonia pattern: A retrospective cohort study

Background Honeycombingon high-resolution computed tomography(HRCT) images is a key finding in idiopathic pulmonary fibrosis(IPF). In IPF, honeycombingarea determined by quantitative CT analysis is correlated with pulmonary function testfindings. We hypothesized that quantitative CT-derived honeycombingarea (HA) might predict mortality in patients with IPF. Materials and methods Chest HRCT images of 52 IPF patients with definite usual interstitial pneumonia(UIP) pattern were retrospectively evaluated. Mortality data up to July 31, 2016, were recorded. Using a computer-aided system, HA and percentage of HA (%HA) were measured quantitatively. Predictors of 3-year mortality were evaluated using logistic regression models. Results The median %HA, %predicted forced vital capacity (FVC) and composite physiologic index (CPI) were 3.8%, 83.6%, and 33.6, respectively. According to GAP (gender, age, and physiology) stage, 20, 14, and 5 patients were classified under stages I-II-III, respectively. Percentage of HA was significantly correlated with %FVC, CPI, and GAP stage (all, p < 0.001). In univariate analysis, %HA, %FVC, and CPI were statistically significant predictors of mortality. In multivariate analysis using the stepwise regression method, only %HA (odds ratio [OR], 1.27; p = 0.011) was a significant independent predictors of mortality. Patients with %HA ≥ 4.8% had significantly lower survival rates than those with lesser %HA (median survival time, 1.3 vs 5.0 years; log-rank test; p < 0.001). Conclusion Quantitative CT-derived HA might be an important and independent predictor of mortality in IPF patients with definite UIP pattern.