The Association of Interstitial Lung Abnormalities and Preserved Ratio Impaired Spirometry With Mortality.

Abstract

Preserved ratio impaired spirometry (PRISm) findings are heterogeneous and include restrictive lung disease. Interstitial lung abnormalities (ILAs) may represent early interstitial lung disease. The relationship between PRISm and ILAs is not well understood. What is the prevalence of ILAs in PRISm compared with normal spirometry findings, what are risk factors for ILAs within PRISm, and how do ILAs modify the association of PRISm and mortality? In Genetic Epidemiology of COPD study participants with baseline spirometry results and chest CT scans, we examined those with normal spirometry findings (FEV₁ ≥ 80% predicted and FEV₁ to FVC ≥ 0.7) and PRISm (FEV₁ < 80% predicted with FEV₁ to FVC ratio ≥ 0.7) with and without ILAs, per Fleischner Society guidelines. We used logistic regression to examine the odds of ILAs in those with PRISm. We modeled all-cause mortality with Cox regression. We evaluated the association of baseline ILA status on change in spirometry findings at follow-up. We included 4,494 participants with normal spirometry findings and 1,262 participants with PRISm. ILAs were present in 93 participants (7%) with PRISm and in 180 participants (4%) with normal spirometry findings. PRISm findings were associated with increased odds (OR, 1.74; 95% CI, 1.33-2.27; P < .001) of ILAs compared with normal spirometry findings. Among participants with PRISm, older age, increased smoke exposure, lower lung function, and increased airway wall thickness were associated with ILA. ILAs were associated with increased mortality (adjusted hazard ratio, 2.58; 95% CI, 1.49-4.45). Our results show that among patients with PRISm, ILAs are associated with increased all-cause mortality, as well as increased age, smoke exposure, lower lung function, and increased airway wall thickness. ClinicalTrials.gov; No.: NCT000608764; URL: www. gov.