Changes in health-related quality of life scores among low-income patients on social welfare programs in Japan during the COVID-19 pandemic: a single-center repeated cross-sectional study

BACKGROUND: Low-income is one of the well-established determinants of people’s health and health-related behavior, including susceptibility to the coronavirus disease 2019 (COVID-19) infection. Two social welfare services are available in Japan to support financial and medical care among low-income patients: Public Assistance (PA), which provide both minimum income and medical costs; and Free/Low-Cost Medical Care (FLCMC), wherein only medical costs were covered. In this study, changes in Health-Related Quality of Life (HRQOL) scores of low-income patients on PA and FLCMC, before and after COVID-19 pandemic, were described and compared against those that are not utilizing the said services (comparison group) to evaluate the contribution of social welfare services in protecting the HRQOL of the beneficiaries during the pandemic. METHODS: We used repeated cross-sectional data of adult beneficiaries of FLCMC and PA, as well as those without social welfare services, who regularly visit the Kamigyo clinic in Kyoto, Japan. We collected the data from 2018 and 2021 using a questionnaire on patients’ socioeconomic attributes and the Japanese version of Medical Outcomes Study 12-Item Short Form Health Survey (SF-12). The Japanese version of SF-12 can calculate the three components scores: physical health component summary (PCS), the mental health component summary (MCS), and the role-social component summary (RCS), which can be transformed to a 0–100 range scale with a mean of 50 and standard deviation of 10. RESULTS: Data of 200 and 174 beneficiaries in 2018 and 2021, respectively, were analyzed. Low-income patients on social welfare services had lower PCS, and RCS than the comparison group in both years. Multiple linear regression analyses with cluster-adjusted standard error estimator showed that the decline in MCS was significantly higher among FLCMC beneficiaries than in those without welfare services (Beta: -4.71, 95% Confidence Interval [CI]: –5.79 to -3.63, p < 0.01), and a decline in MCS among PA recipients was also observed (Beta: -4.27, 95% CI: -6.67 to -1.87 p = 0.02). CONCLUSIONS: Low-income beneficiaries of social welfare may have experienced mental health deterioration during the COVID-19 pandemic. To maintain healthy lives during the pandemic, additional support on mental health for low-income recipients of social welfare services may be required. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12889-022-14597-5.