Background: Lung cancer is a common comorbidity of idiopathic pulmonary fibrosis (IPF) and has poor outcomes. We aimed to determine the prevalence of and risk factors for postoperative pulmonary complications (PPCs) in IPF patients with non-small cell lung cancer (NSCLC) to select optimal candidates for surgical resection and to develop a novel scoring system to predict mortality among surgical candidates.

Methods: For 225 patients consisting of two cohorts who were diagnosed with IPF and underwent curative resection for NSCLC, we developed a nomogram using logistic regression analysis that included: age, sex, diabetes, American Society of Anesthesiologists class, diffusing capacity and extent of surgery. Validation of the nomogram was assessed by discrimination and calibration applied to a separate cohort of 51 patients.

Results: Of 276 patients, 95 (34%) had PPCs. A multiple logistic regression model revealed six risk factors (with scores in parentheses): age ? 67 years (1 point), male (1 point), diabetes (1 point), American Society of Anesthesiologists class ? 3 (1 point), diffusing capacity ? 64% (1 point) and extent of surgery (2 points). The area under the curve was 0.76 (95% CI, 0.70-0.83) in the derivation cohort and 0.72 (95% CI, 0.56-0.88) in the validation cohort with calibration (slope = 0.61).

Conclusions: PPCs frequently developed in patients with IPF who received curative resection for NSCLC. This nomogram developed from two derivation cohorts and externally validated in an independent set based on six easily accessible clinical variables, which guide treatment decision-making in these patients.