Effects of Demographic and Socio-Economic Factors on Investigation Time of Lung Cancer Patients in Denmark: A Retrospective Cohort Study.

Background: Lung cancer is one of the most common cancer types worldwide. The significance of the individual socio-economic position on the delay in lung cancer diagnosis has not been properly investigated. The purpose of this nationwide population-based study is to examine the association between position and the length of the primary investigation for lung cancer. Materials and Methods: This register study was based on all lung cancer patients in Denmark who were diagnosed in 2012 to 2017, in total 28,431 patients. We used a multivariate logistic regression model and multivariate zero-inflated negative binomial model to estimate the effect of education level, family income, difficulty of transport, and cohabitation status on the length of the primary investigation. Results: We found that the patients' income, difficulty of transport, and cohabitation status were associated with the length of the primary investigation. The chance of carrying out the investigation process within 24 days is higher for patients with a high income (adjusted OR = 0.86 with 95% CI (0.81; 0.91)), lower for patients with troublesome transport (adjusted OR = 0.67 with 95% CI (0.61; 0.72)), and lower for patients living alone (adjusted OR = 0.93 with 95% CI (0.88; 0.99)). Conclusion: Several socio-economic factors are associated with the length of the primary lung cancer investigation. To ensure that all patients receive the most appropriate health care and to avoid extra investigation time, clinicians may pay extra attention to patients who are less fortunate due to low income, troublesome transport to the hospital, or living alone.