Lung cancer in patients with and without rheumatoid arthritis: A propensity score‐matched survival analysis cohort study

BACKGROUND: Connective tissue disease increases the risk of lung cancer, but whether rheumatoid arthritis (RA) has an effect on the overall survival (OS) rate in this population has not been well studied. METHODS: Patients diagnosed with lung cancer between January 2015 and December 2017 were enrolled in this retrospective analysis. Propensity score matching was performed to balance the baseline of the two groups, whereas the differences between patients with and without RA were compared using survival analysis. Further, the effects of interstitial lung disease (ILD) and qi deficiency on survival in cases of RA with lung cancer were examined. Cox regression analysis was applied to predict the factors that influenced the survival of lung cancer to one year. RESULTS: Overall, 154 lung cancer patients, including 136 (88.3%) without RA and 18 (11.7%) with RA, were included. Two comparison cohorts were matched by 1:2 propensity score matching, which yielded 18 lung cancer patients with RA and 36 lung cancer patients without RA. Ultimately, the survival prognosis of lung cancer and RA was worse than that without RA, that of patients with ILD with RA and lung cancer was worse than that among those without RA, and that of patients with qi deficiency with RA and lung cancer was worse than that among those without RA. CONCLUSIONS: The survival prognosis of lung cancer patients with RA is worse than that of those without RA. ILD and qi deficiency promote reduced survival when found in conjunction with RA in patients with lung cancer.