The present study estimated the number of future short-stay service recipients by the CNLTC level from 2020 to 2045 using the machine learning approach. The large correlation coefficients between the estimated and actual numbers of short-stay service recipients suggest high accuracy of the estimates obtained by the machine learning processes in this study. This indicates that machine learning estimation can be an effective approach to estimate the number of nursing care service recipients in an area of Japan. Based on the estimates obtained and the cartograms, the changing trends of the numbers and spatial distributions of short-stay service recipients in Hokkaido were reviewed. Additionally, issues in future human resource allocations for the service were discussed.
Changing trends of the numbers of short-stay service recipients
As shown in Table 2, the total estimated number of short-stay service recipients reaches 18,016 in 2035 and then starts to decline even though the whole population of Hokkaido is constantly decreasing. The estimated number for 2045 is 11,065, which is 61% of that for 2035. Such change in the estimated numbers can be attributed to the aging of those born during the first baby boom from 1947 to 1949 in Japan.
Among the five CNLTC levels, the estimates suggest that those at levels 2 and 3 are the main users of short-stay service. The estimated numbers for levels 2 and 3 accounts for more than half of the total estimated numbers for each year. Such trend is the same as the present situation. There can be more need for short-stay service in those at level 2 or 3 compared with those at level 1 who are more independent as well as those at levels 4 and 5 who may choose facility care service.
In particular, there is a significant increase in the estimated number of the service recipients at level 3 in the years 2030 and 2035. Moreover, the proportion of the service recipients at level 3 is estimated to increase to >30% of the total in 2030 and 2035, whereas the proportion of those at level 1 decreases. These results can also be associated with aging of the first baby boomers. In 2035, the first baby boomers will be approximately 85 years old in Japan. Consequently, the number of the elderly people who need assistance with all aspects of daily living and could be categorized in level 3 will probably increase in that year. However, in 2040 and 2045, the percentage of people at level 3 is predicted to decrease, whereas that of people at level 1 is predicted to increase. This may be due to the transaction of the main service recipients from the first baby boomers to the next younger generation.
Changes of spatial distributions of short-stay service recipients
As the areas with darker colors in all the cartograms (Fig. 2) indicate, service recipients are concentrated in areas A–G, which are the high population centers in Hokkaido from 2020 to 2045. In particular, from 2020 to 2030, area A is significantly expanded especially in the cartograms for levels 2 and 3. In addition, areas B–G are also expanded according to the estimated numbers although not as much as area A. Consequently, the maps for levels 2 and 3 from 2020 to 2030 are heavily distorted. These suggest that most of future short-stay service recipients are greatly concentrated in the population centers, especially in the area of Sapporo City and its surrounding cites (area A), from 2020 to 2030. Such concentration of the service recipients is also illustrated in Table 2. Nearly 80% of the estimated service recipients are concentrated in areas A–G from 2030 to 2045.
In 2035, however, only the cartogram for level 3 shows the same concentrations of the service recipients as those in the earlier years, reflecting an increase of the numbers of recipients at level 3. Actually, as shown in Table 2, in 2035, compared with 2030, the estimated number of recipients at level 3 increases from 6075 to 6674, whereas that of level 2 decreases from 3477 to 3299.
In 2040 and 2045, service recipients are still concentrated in the populated areas highlighted with darker colors. However, as the cartograms for those years with fewer distortions suggest, excessive concentrations of the service recipients in area A are not predicted in 2040 and 2045 at any level of the CNLTC. The main reason for this is the significant decline in the estimated number of the service recipients at level 3 in 2040 and 2045 as noted earlier.
Issues for future resource allocations based on the estimates
On the basis of the results of the estimations, there are three issues for the effective allocations of human resources for future short-stay services in Hokkaido. The first one is the allocation of adequate human resources to the areas where the service recipients are estimated to be concentrated. This study predicted that the service recipients would heavily concentrate in the Sapporo area. Although there has been a high concentration of healthcare workers in the Sapporo area, it should be examined whether that will be sufficient in the future as well. Moreover, in the other areas where the service recipients were also estimated to be concentrated, there may be a shortage of personnel. It is necessary to take measure to spread the human resources concentrated in the Sapporo area to the other areas in Hokkaido. For future discussions, the accurate estimates of care supplies are also required in addition to the estimates of care demands.
The second challenge is to ensure that there are sufficient personnel to meet the increase in the number of the service recipients at level 3 in 2030 and 2035. Those at level 3 need more assistance than those at levels 1 and 2. Compared with those at level 2, more personnel may be needed to provide those at level 3 with quality care. As the cartograms for level 3 illustrate, the increase in the number of those at level 3 is significant in the Sapporo area. This means that the Sapporo area must deploy human resources to meet the growing number of service recipients who need more care by 2030.
The third one is a possibility of severe staff shortages in 2040 and 2045. Although it is predicated that the total number of the service recipients will drop to 61% of those in 2035, it is still a possibility for severe staff shortages in 2040 and 2045. It is projected that people aged ≥65 years will account for 40% of the population in those years in Hokkaido. This indicates a significant decline in the working population. To overcome this challenge, the use of technologies including robots and artificial intelligence has been examined [16-19]. However, such technologies have been rarely used in nursing care for elderly people in Japan . Ishiguro  suggests that a lack of adoption of care robots to nursing care settings is due to a belief that human hands should undertake care in Japan as well as a lack of information about such technologies among healthcare and care workers. Future studies must tackle not only technological issues but also those in the improvements of accepted modern associative technologies of care among the general people and those in nursing care services.