Using methods and data that are less common in this field of research, this study analyzed the regional differences in medical expenses per capita in Japan after age adjustment.

First, regional differences were found to have widened in almost all cohorts across a five-year period in the sense that the change in per capita medical expenses by cohort between fiscal years 2010 and 2015, when the censuses were conducted, was positively correlated with those in fiscal year 2010. Large increases were experienced by a few different prefectures depending on young or old cohorts. Regression analyses were conducted to regress the change in per capita medical expenses by cohort on common factors such as per capita income and medical supply system factors, and cohort-specific factors such as a special health checkup rate. A statistically significant positive relationship was found between medical expenses and number of doctors for the four old-age cohorts, and no negative relationship was significant for other cohorts. A statistically significant positive relationship was found between medical expenses and MRI units for the three middle-aged cohorts（and for one cohort with a statistically significant negative relationship）. These results were consistent with the result of the medical expense function for the prefectures.

Next, as a complementary analysis, we analyzed the correlation between the standardized claim data ratio and per capita outpatient medical expenses in fiscal year 2015. Many items with a strong relationship with medical expenses concerned home medical treatment, inspection, and administration of drugs and treatment. The relationship was stronger between the outpatient treatment fee and the initial treatment plus related examinations, which is assumed to involve stronger action from the medical demand-side, than between the outpatient treatment fee and the reexamination plus related examinations to it. In addition, medical supply system factors had an important relationship with initial treatment plus related examinations.

Background: Socioeconomic and psychosocial status affect the health and treatment adherence of patients, especially if patients are impoverished and isolated. Yet, few standard procedures for addressing these social risks have been available in clinical settings. Social prescribing may supply the procedures necessary to address these risks; thus, it has attracted much attention recently. We attempt to define social prescribing through a literature review of currently available global evidence of the effectiveness of social prescribing activities, and also through a review of Japanese literature on similar activities. Further, this study aims to discuss the challenges and opportunities involved with the implementation of policy that addresses patients' social risks at healthcare institutions in Japan.

Method: Searches were conducted via PubMed, Web of Science, Google Scholar, and Japan Medical Abstracts Society database. We collected data on countries and regions where social prescribing is used, as well as its methods, definitions, and effects. Based on the review, we defined social prescribing comprehensively. In addition, we discussed the challenges and opportunities for implementing social prescribing activities in Japan.

Results: We included 34 studies and reports. Social prescribing was mostly reported from the UK. Social prescribing enables healthcare professionals to refer patients to a link worker, to co-design a non-clinical social prescription to improve their health and wellbeing. Empirical evidence suggests that social prescribing may be effective in reducing medical expenditure and unnecessary consultations. Based on our review, we defined social prescribing as: the activities of healthcare professionals who evaluate a patient's social needs and connect the patient to social resources, as well as co-design the patient's care with social resources to improve their health and wellbeing. Activities that matched with the definition were also reported in Japan.

Discussion: According to our review, in order to implement similar policies in Japan, it may be necessary to evaluate the effectiveness of social prescribing activities, establish standardized diagnostic tools for patients' social risks, strengthen community governance of social prescribing activities, and consider how social prescribing is labeled.