Outline of the Healthcare System in Japan

The Japanese health insurance system initially started for workers in Japan during the 1920s when the employment-based health insurance plan was established. The universal health insurance system, which is regulated by the Japanese government, has provided comprehensive coverage to all citizens since 1961. There are several plans within the universal health insurance system based on age, employment status, and/or place of residence. Two major plans of health insurance are society-managed, employment-based health insurance and national health insurance. In general, the former covers workers at companies, while the latter covers the self-employed and unemployed.

The health insurance system in Japan covers all permanent residents by public medical insurance. This includes both Japanese and non-Japanese citizens.

Characteristics of Japanese Universal Health Insurance System [1]

  • Covering all permanent residents by public medical insurance

  • Freedom of choice of medical facilities

     (Free access)

  • High-quality medical services with low costs

All health insurance plans provide the same packages of medical care benefits, as determined by the national government. These benefits include hospital fee, outpatient fee, mental healthcare, prescription drugs, home healthcare, and most dental care. Patients are covered by some forms of public insurance system at relatively lower cost, including certain premiums and copayments (10–30%). Home care services are also covered by long-term care insurance. The benefit prices of medical services as well as drugs and approved medical devices are strictly regulated by the government and revised every other year. Private health insurance can provide only a supplementary service in Japan.

The premium rate for public health insurance is based on the individual’s income, place of residence, and ability to pay. Cost-sharing varies according to one’s age (Fig. 14.1). Patients’ copayment for medical expenditure is basically 30%, with the exceptions for children under the age of 6 (20% copayment) and persons over the age of 70 with low incomes (10% copayment) [2]. In addition, there is a high-cost medical care benefit system. It is to avoid copayments made for medical costs becoming too expensive for family budgets (the maximum copayment is set up according to insured persons’ income and age).

Fig. 14.1
figure 1

Overview of medical services in Japan

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The Japanese healthcare system is characterized by free access to healthcare facilities and good quality of medical care with comparably low prices [2]. Patients can receive medical services of any physician or at any medical facility of their choice.

This universal health insurance system has been maintained for more than 50 years. Japan has the world’s longest life expectancy although the financial management of its health care system has been growing increasingly challenging. Japan is currently facing problems associated with its rapidly aging society; the number of elderly population is expected to grow from the current 16 million to 20 million by 2020. In contrast, the working population is expected to decline from 109 million to 100 million during the same period [1]. People aged 65 or older reached 27.3% of Japanese population in 2016 and are expected to reach 39.4% by 2055; the population of those over 75 years old will peak by 2025 [1]. The government introduced a medical care system for the elderly in 2008: The late-stage medical care system for the elderly covers those over 75 years old and early-stage medical care for the elderly aimed at 65–74-year-old patients.

Health-Related Outcome Assessments in Japan

The MOS 36-Item Short-Form Health Survey [3] and Euro-QOL 5D are commonly used health-related patient-reported outcome measurements in Japan. These measurements are validated in Japanese population [4, 5]. Users need to apply to the organizations for licensing [6, 7]. There are a variety of disease-specific measures of spine healthcare quality that impact evaluation of Japanese spine patients.

Disease-Specific Types of Health-Related Outcome Assessments: Cervical Spinal Disorders

Nurick Scale

The Nurick scale is physician-based measurement developed in 1972 [8, 9]. The Nurick scale is mainly focused on abilities to walk and to work. Patients are graded from 0 to 5 with higher scores indicating more disabled. The Nurick scale can simply evaluate ambulatory function that is a critical ability for patients. On the other hand, the Nurick score lacks evaluation of the motor function in the upper extremities and sensory function. There is currently no validated Japanese version available.

The Japanese Orthopedic Association (JOA) Scoring System for Cervical Spondylotic Myelopathy

The JOA scoring system for cervical spondylotic myelopathy (CSM) is a disease-specific, physician-reported scoring system developed in 1976 [10]. The scoring system was revised in 1994 [11]. The current JOA scoring system consists of seven domains: motor function in the fingers, motor function in the elbow and shoulder, motor function in the lower extremities, sensory function in the upper extremities, sensory function in the trunk, sensory function in the lower extremities, and bladder function. Calculation of the JOA score is straightforward. Total score can range from −5 to 17, counted by 0.5 point increments, with higher score indicating better function.

Interobserver and intraobserver reliability was tested by the committees of JOA [12]. The JOA scoring system has been widely used in daily clinical practice in Japan. Nonetheless, there have been some critiques on the JOA scoring system. The domain of the fingers’ function includes an ability to use chopsticks. Although chopsticks become spread in western countries, regular use of chopsticks is limited to East Asia. Thus, some authors have developed modified JOA scoring systems that omit the use of chopsticks [13, 14]. These modified JOA scores correlate with the original JOA score; however, the users need to recognize that the modified JOA scoring systems are not identical to the original JOA scoring system [15].

Second, there is not enough evidence of weighting of each score in each domain. It is unknown whether 1 point in motor function in the finger is equivalent for patient’s activities of daily life to 1 point in motor function in the lower extremities. Third, statistical power is limited because the score distributes within a narrow range. To improve statistical power, the recovery rate proposed by Hirabayashi is often used [16].

The Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ)

The JOACMEQ is a disease-specific, patient-reported outcome measurement developed in 2007 (Table 14.1) [17]. The JOACMEQ was developed to cover the drawbacks of the JOA scoring system. The JOACMEQ consists of five domains: cervical spine function, upper extremity function, lower extremity function, bladder function, and quality of life. Factor loading of the questions is set up so that scores in each domain range from 0 to 100, with higher scores indicating a better condition and higher function. Reliability, internal consistency, criteria validity, and clinically important difference are tested when the JOACMEQ was developed [18,19,20].

Table 14.1 Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire
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A treatment for a patient is determined to be effective when the score change (the postoperative score-the preoperative score) of the patient is more than 20 points or the postoperative score of the patient is more than 90 points [20].

A drawback of this assessment tool is its complicated calculation of scores. The excel file for calculation can be downloaded from the developer website [21]. As the JOACMEQ is still a new scoring system, there are limited numbers of researchers that use the JOACMEQ as their primary outcome assessment tool.

Disease-Specific Type of Health-Related Outcome Assessments: Lumbar Spinal Disorders

Roland-Morris Disability Questionnaire (RMDQ)

RMDQ is a disease-specific, patient-reported measurement developed in 1983. RMDQ is a common assessment tool for low back pain in Japan. The Japanese version was reported in the literature [22].

Oswestry Disability Index (ODI)

ODI is a disease -specific, patient-reported measurement developed in 1980. ODI is a common assessment tool for lumbar surgery in Japan. Validated Japanese versions were reported in the literatures [23].

The Japanese Orthopedic Association (JOA) Scoring System for Low Back Pain

The Japanese Orthopedic Association (JOA) scoring system for low back pain (LBP) is a disease-specific, physician-based scoring system developed in 1986 [24]. Since then, the JOA scoring system for LBP has been a common assessment tool for lumbar surgery in Japan. The JOA scoring system consists of four main domains: subjective symptoms, objective symptoms, activity of daily life, and bladder function, with subscales. Its total score can range from −6 to 29, counted by 1 point, with higher score indicating better function. Interobserver reliability, reproducibility, and validity were reported in the literatures [22, 24, 25]. As similar to the JOA scoring system for CSM, there is no sufficient evidence for weighting of each question.

The Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ)

The JOABPEQ is a disease-specific patient-reported measurement developed in 2007 (Table 14.2) [20, 26, 27]. The JOABMEQ consists of five domains: low back pain, lumbar function, walking ability, social function, and mental health. Each questionnaire was created with reference to the short form health survey with 36 items and the Roland-Morris Disability Questionnaire. As with the JOACMEQ, reliability, internal consistency, criteria validity, and clinically important difference were tested when the JOABPEQ was developed. When the score change is more than 20 points, or the postoperative score is more than 90 points, the treatment is judged as effective [20, 28, 29].

Table 14.2 Japanese Orthopaedic Association Back Pain Evaluation Questionnaire
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