Imaging Patterns Are Associated with Interstitial Lung Abnormality Progression and Mortality

Abstract

Rationale: Interstitial lung abnormalities (ILA) are radiologic abnormalities on chest computed tomography scans that have been associated with an early or mild form of pulmonary fibrosis. Although ILA have been associated with radiologic progression, it is not known if specific imaging patterns are associated with progression or risk of mortality. Objectives: To determine the role of imaging patterns on the risk of death and ILA progression. Methods: ILA (and imaging pattern) were assessed in 5,320 participants from the AGES-Reykjavik Study, and ILA progression was assessed in 3,167 participants. Multivariable logistic regression was used to assess factors associated with ILA progression, and Cox proportional hazards models were used to assess time to mortality. Measurements and Main Results: Over 5 years, 327 (10%) had ILA on at least one computed tomography, and 1,435 (45%) did not have ILA on either computed tomography. Of those with ILA, 238 (73%) had imaging progression, whereas 89 (27%) had stable to improved imaging; increasing age and copies of MUC5B genotype were associated with imaging progression. The definite fibrosis pattern was associated with the highest risk of progression (odds ratio, 8.4; 95% confidence interval, 2.7-25; P = 0.0003). Specific imaging patterns were also associated with an increased risk of death. After adjustment, both a probable usual interstitial pneumonia and usual interstitial pneumonia pattern were associated with an increased risk of death when compared with those indeterminate for usual interstitial pneumonia (hazard ratio, 1.7; 95% confidence interval, 1.2-2.4; P = 0.001; hazard ratio, 3.9; 95% confidence interval, 2.3-6.8;P < 0.0001), respectively. Conclusions: In those with ILA, imaging patterns can be used to help predict who is at the greatest risk of progression and early death.

Keywords: idiopathic pulmonary fibrosis; imaging pattern; interstitial lung abnormalities; mortality; progression.

Figures

Figure 1.

Serial chest computed tomography scans from three participants with interstitial lung abnormalities. (A1–C1) Representative axial images from computed tomography scan 1. (A2–C2) Representative axial images from computed tomography scan 2. Participant A is indeterminate for usual interstitial pneumonia (UIP) on scan 1 (A1) and progressed to a probable UIP pattern (A2). Participant B has a probable UIP pattern on scan 1 (B1) and progressed to a UIP pattern (B2). Participant C had a UIP pattern on scan 1 (C1) and had imaging progression that remained consistent with a UIP pattern (C2).

Figure 2.

Kaplan-Meier survival curves showing percent survival, comparing participants without interstitial lung abnormalities (ILA) with those with ILA, first with ILA subset based on consistency with an idiopathic pulmonary fibrosis diagnosis, and then by the presence of definite fibrosis (pulmonary parenchymal architectural distortion). UIP = usual interstitial pneumonia.