Abnormal spirometry is used to diagnose chronic obstructive pulmonary disease (COPD). On the other hand, Spirometry may underestimate the consequences of smoking, leaving out smokers with respiratory illnesses who have only minor or no airflow obstruction. To create a multidimensional description of a lung-related “resilient smoker” used in research studies, and then to utilize this definition to identify a resilient smoker subgroup in the SPIROMICS (Subpopulations and Intermediate Outcome Measures In COPD Study) cohort. A panel of COPD experts participated in a three-round modified Delphi poll to identify and agree on clinical and radiographic areas in a lung-related resilient smoker definition. On a 5-point Likert scale, consensus on dimensions of resilience was defined as 80% of experts voting “yes” or “strongly agree.” SPIROMICS was used to identify resilient smokers using the Delphi-derived definition of resilience, subsequently described using known COPD biomarkers.

Cough and sputum production, dyspnea, radiographic measurements of emphysema and small airway disease, exacerbations, and fall in forced expiratory volume in 1 second were among the six diagnostic elements that reached consensus. Although spirometry identified 892 SPIROMICS participants as smokers with retained lung function, only 149 (16.7%) fit the criterion of resilient smokers. CRP (C-reactive protein) and sTNFRSF1A (soluble tumor necrosis receptor factor1A) blood biomarker expression were lower in resilient smokers than in nonresilient smokers (P=0.02 and P=0.03). Based on the prevalence of harmful effects of smoking on the lungs, a Delphi-derived consensus definition of resilient smokers categorized 83.3% of smokers with maintained spirometry as “nonresilient.” CRP tests revealed that resilient smokers were biologically unique from nonresilient smokers.