Background: Social determinants of health (SDHs) are social factors that affect human health; loneliness and social isolation are core SDH factors. There is a possibility that SDHs are related to passive decision-making. However, few studies have evaluated SDHs, especially social isolation and loneliness, among lung cancer patients. This study aims to investigate the effects of social isolation and loneliness on the diagnosis and treatment of Japanese lung cancer patients.
Methods: This is a prospective cohort study that was conducted in a tertiary referral hospital in Japan (University Hospital Medical Information Network registration: UMIN000031810). The enrollment period was between April 2018 and March 2020. Patients with clinical and/or pathological diagnosis of lung cancer were enrolled in this study. Exposures were social isolation and loneliness, and main outcomes were diagnosis methods and whether the initial treatment involved active therapy or best supportive care (BSC). The confounding factors were defined as sex, age, smoking status, respiratory symptoms, weight loss, presentation with any symptoms, Eastern Cooperative Oncology Group (ECOG) performance status, tumor nodes metastasis (TNM) classification, driver gene mutations [i.e., epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK)], and programmed death-ligand 1 (PD-L1) tumor proportion score.
Results: The study enrolled 264 patients who were divided into quartiles according to their loneliness scores and into two groups according to the social isolation level. Univariate analysis, complete case analysis, and multivariate analysis with multiple imputation failed to detect significant differences in diagnostic method or initial treatment strategy according to loneliness or social isolation level.
Conclusions: Physicians may not need to consider a patient's loneliness and/or social isolation when diagnosing lung cancer and selecting treatment under universal health insurance coverage. Further studies are needed to understand the influences of loneliness and social isolation on the prognosis of lung cancer patients.
Keywords: Social determinants of health (SDHs); loneliness; lung cancer; social isolation.