Health Insurance and Its Psychosocial Correlates in Patients with Advanced Lung Cancer in Japan.

Introduction: Japan has a national health insurance system that covers at least 70% of regular medical costs and provides additional benefits for high medical costs. In addition, >60% of the population holds private health insurance to reduce financial toxicity. However, there has been a lack of real-world data on private health insurance in the oncology setting in Japan. Methods: A cross-sectional survey of health insurance was conducted at 16 hospitals in Japan between 2013 and 2016. Patients were eligible if they were newly diagnosed with clinical stage IIIB or IV lung cancer. Data collected included patients' health insurance, clinical and sociodemographic characteristics, and self-reported outcomes 3 months after diagnosis. Results: Of the 147 patients, 114 (77.6%) had private health insurance. Patients with private health insurance were significantly younger (p = 0.028), had better performance status (p = 0.029), and reported better quality of life (p = 0.017), specifically in social (p = 0.039) and emotional (p = 0.011) well-being. There were no significant associations between having private health insurance and treatment details, medical satisfaction, or financial issues. Most patients (99.3%) reported that national health insurance is necessary. A substantial proportion of patients (9.8%), particularly those without private health insurance (19.4%), reported that private health insurance is not necessary. Conclusions: Having private health insurance was associated with better quality of life, though there were no significant differences in medical care or financial issues. Our findings suggest that private health insurance plays an auxiliary role in accessing medical care for patients with advanced lung cancer in Japan.