Introduction

The aging of society and the resulting increase in medical expenses are serious concerns for developed and developing countries, yet to be faced with aging [1,2]. Japan has received much international attention for maintenance of good health in the population, by way of free access to medical care and low medical fees under the universal health insurance coverage [3]. However, the burden on healthcare providers and public healthcare costs are expected to increase rapidly since Japan is the fastest aging country in the world [4,5]. In Japanese remote and isolated islands, there are issues regarding rapid population aging, estimations of the actual medical supply and demand, and the future reconstruction needed in consideration of the geographical limitations.

White et al. proposed a framework for medical supply-and-demand in their article titled, “The Ecology of Medical Care” [6]. Based on their framework, surveys on the actual ecology of medical care have also been conducted in Japan, focusing on urban areas [7,8]. In contrast, fewer studies have reported on the ecology of medical care in remote and isolated islands [9].

Our study surveyed the actual status of medical supply-and-demand, in relation to all the patients who visited the Yonaguni Municipal Clinic, the only medical facility in Yonaguni Island, located in the westernmost region in Japan, in order to assess the quality of healthcare, and adjust the quantity of supply-and-demand for medical services in a rural area where medical access is geographically limited. Our results have been compared with those of two previous surveys carried out in rural Japan; Fukui et al.(2017) carried out the most representative report on the ecology of medical care in Japan [8], and Kaneko et al.(2017) researched a different remote island in Okinawa, Japan [9].

Materials and methods

This study was approved by the Ethics Committees of the Japan Association for Development of Community Medicine (ID: 16–02) and the Hirosaki University School of Medicine & Hospital (ID: 2016–1113).

As of June 2016, the Yonaguni Municipal Clinic is the only medical facility in Yonaguni Island, a remote island in Okinawa Prefecture, Japan (area, 28.9 km²; population, 1,696 (males, 812); population aging rate >65 years, 18.5%; proportion of young people <15 years, 12.5%). The island is located 510 km from the main island of Okinawa (90 minutes by airplane: one-way fare approximately 13,300 Japanese yen). The clinic had six staff members, including one physician (one of the present authors, HN), three nurses, and two clerks. No inpatient treatment was available, but overnight observation was available in the outpatient treatment room. A 24-hour emergency call system was in place (approximately 50 emergency calls or patient consultations per month during the nighttime). The available medical equipment included a blood-test analyzer (e.g., blood count and general biochemical examination), a microscope for examining bacteria (e.g., Gram stain), an electrocardiography system, roentgenographic equipment, diagnostic ultrasound equipment, and computed tomography (CT) equipment. There is no facility on the island of Yonaguni that provides alternative or complementary medicine.

The participants in our study were all the patients who had visited the Yonaguni Municipal Clinic between July 2015 and June 2016. The following evaluation items were retrospectively counted: the rate of clinic visits per 1,000 persons per month, the rate of referrals to off-island medical facilities (e.g., hospitals and specialist clinics), the rate of referrals to off-island emergency departments, the rate of off-island hospitalizations after referral, the rate of home visits in Yonaguni Island, and the rate of overnight observations at the clinic. The unit of analysis was one per -month, indicating receipt of services in a healthcare setting at least once in a month. Our Yonaguni survey was evaluated using a standard deviation (SD) because it represented a full-number survey. We directly compared the rate of clinic visits per 1,000 persons per month to those recorded in other Japanese studies analyzing visits, referrals, hospitalizations, emergencies, and home visits, using a 95% confidence interval (CI).

Using the software Easy R [10], we performed descriptive analyses to evaluate the healthcare-seeking behavior per 1,000 inhabitants over a 1-month period, based on the actual number of visits. We calculated the 95% CI for event rates with either a normal distribution (≥10 events) or a Poisson distribution (<10 events).

Results

In total, 6,197 patients (males, 46.3%) visited the clinic. Of these, 827 (males, 50.2%) were aged <15 years; 3,103 (males, 49.6%) were aged 15–65 years; and 2,267 (males, 40.5%) were aged ≥65 years. The rate of clinic visits per 1,000 persons per month was 516.4 (SD 28.1, 95% CI: 500.5–532.3). The rate of referrals to the outpatient departments of other medical facilities was 14.0 (SD 3.9, 95% CI: 11.8–16.2). The rate of off-island referrals to the emergency departments of other medical facilities was 3.8 (SD 2.1, 95% CI: 2.6–5.0). The rate of hospitalizations at other medical facilities after referral was 4.8 (SD 2.6, 95% CI: 3.3–6.2). The rate of home visits in Yonaguni Island was 3.2 (SD 1.7, 95% CI: 2.2–4.1). The rate of overnight observations at the clinic was 0.3 (SD 0.5, 95% CI: 0.1–0.9). The details and summary are shown in Fig 1 and Table 1. The comparison between our study and other areas in Japan is shown in Table 2.

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Fig 1. Medical ecology in the present study of Yonaguni island residents: Rates of healthcare-seeking behaviors per 1,000 persons per month.

https://doi.org/10.1371/journal.pone.0199871.g001

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Table 1. Rates of healthcare-seeking behavior per 1,000 persons per month in Yonaguni island.

https://doi.org/10.1371/journal.pone.0199871.t001

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Table 2. Comparison of rates of healthcare-seeking behaviors per 1,000 persons per month between our study and previous studies in Japan.

https://doi.org/10.1371/journal.pone.0199871.t002

Discussion

In this study, we assessed the ecology of medical care in Yonaguni Island, an isolated island where access to other medical facilities is geographically limited, by investigating the healthcare-seeking behaviors of all patients, and evaluated the comparison to other rural areas.

The rate of visits to primary care clinics was higher in our study than that reported by Fukui et al. (2017) [8] who studied urban and rural areas in Japan. The discrepancy was attributable to the isolated nature of the island, including limited access to other medical facilities, difficulty purchasing over-the-counter drugs (owing to the absence of pharmacies), and the extreme scarcity of medical services, including alternative medicine, other than the clinic [11, 12]. The rate of visits to primary care clinics in our study was also higher than that reported in the study by Kaneko et al. (2017) [9]. This was because the island they studied was closer to the main island of Okinawa (41.1 km away), whereas Yonaguni Island is located 507.8 km away. Therefore, the factors thought to underlying the increased number of visits to the clinic were poor access to advanced medical facilities, lack of medical services other than the clinic, and the adequate allocation of healthcare resources through the gatekeeping role of the clinic.

The rate of visits to the outpatient department of other medical facilities in our study was lower than that reported by Fukui et al. (2017) [8]. This was due to reasons such as difficulty in visiting advanced medical facilities due to time and economic constraints, and the function of the only clinic in the island as a gatekeeper, which enabled adequate allocation of medical resources. The rate of visits to the outpatient departments of other medical facilities in our study was lower than that reported by Kaneko et al. (2017) [9]; this finding may be explained by high diagnostic accuracy in emergency cases, due to the availability of CT equipment (including remote reading) at the Yonaguni Municipal Clinic, despite the difference in access to advanced medical facilities on the main island of Okinawa.

There were no significant differences in the rates of referral to emergency departments of off-island medical facilities and hospitalizations between our study and previous studies [8,9]. This could be explained by the fact that the incidence of diseases presenting as emergencies and/or requiring hospitalization did not differ from one district to another, and that there was ready access to advanced medical facilities in emergency cases.

The rate of home visits, 3.7 per 1,000 persons per month in Okinawa Prefecture (population size 1,423,000 in September 2016; population aging rate >65 years, 19.4%) in October 2014, was the lowest in Japan [13]. The rate of home visits, 3.2 (95% CI: 2.2–4.1) per 1,000 persons per month in our study of Yonaguni Island (population size 1,696 in June 2016; population aging rate >65 years, 18.5%) was about the same as in Okinawa Prefecture.

The rate of overnight observations at the clinic per 1,000 persons per month in our study was 0.3 (95% CI: 0.1–0.9). In some countries, overnight observation is provided as a service for patients who may require inpatient care in the emergency department or another area of the hospital, but not in facilities are primary care centers. We suggest that the provision of overnight observation may have helped to reduce, not only the number of hospitalizations [14], but also the burden on other medical facilities, and the time and economic constraints faced by patients. Healthcare in rural areas in Japan might be supported by specific and devoted efforts, including the overworking of healthcare staff, a problem for which Japan is world-famous [15].

We attempted to compare the findings of our study with those obtained in rural parts of other countries, including Australia [16], Belgium [17], China [18], Sweden [19], the U.S. [20] (S1 Table). However, the following factors made it impossible to apply the appropriate statistical methods: few raw data were disclosed in published studies (e.g., unavailability of data from rural areas, unseparated data for urban and rural areas); there were significant differences in the types of areas researched (e.g., metropolitan/non-metropolitan, rural/urban); there were substantial differences in healthcare systems and access to medical facilities (e.g., patients with or without private/public insurance, missing data from rural areas); there were also large differences of the adoption rate for alternative medicine worldwide, especially high rate in Asia, which affected healthcare-seeking behaviors (e.g., date with or without alternative medicine).

Isolated island societies are facing aging and shrinking populations. The following strategies are needed to develop sustainable and effective medical systems for the inhabitants of isolated islands: 1) establishment of an efficient referral system for patients requiring emergent treatment or advanced medical care [21, 22], 2) introduction of cost-effective medical interventions [6] to accommodate for more patients who require home visits and end-of-life care [4], and 3) enhancement of the effective utilization of mobile health services by using information and communication technology [23]. We hope that these strategies will be relevant to other countries that will soon be faced with aging populations.

Conclusions

The rate of clinic visits was higher, and the number of referrals to off-island medical facilities was lower, than those found in previous studies. There was no significant difference between the present study and previous research in relation to the rate of hospitalizations and referrals to off-island emergency departments. This study has described the ecology of medical care in Yonaguni Island, an isolated island, where access to other medical facilities is geographically limited, by assessing the healthcare-seeking behaviors of all patients who visited the island’s single clinic.

Conflicts of interest

None.

Supporting information

Acknowledgments

The authors thank all the people living on Yonaguni Island, the staff of the Yonaguni Municipal Clinic, and Eisaku Sakihara M.D. of the Okinawa Community Medicine Support Center, for their valuable support, as well as the medical students and residents who visited the island for training and participated in the study.