Shunya Ikeda

What has made the population of Japan healthy

People in Japan have the longest life expectancy at birth in the world. Here, we compile the best available evidence about population health in Japan to investigate what has made the Japanese people healthy in the past 50 years. The Japanese population achieved longevity in a fairly short time through a rapid reduction in mortality rates for communicable diseases from the 1950s to the early 1960s, followed by a large reduction in stroke mortality rates. Japan had moderate mortality rates for non-communicable diseases, with the exception of stroke, in the 1950s. The improvement in population health continued after the mid-1960s through the implementation of primary and secondary preventive community public health measures for adult mortality from non-communicable diseases and an increased use of advanced medical technologies through the universal insurance scheme. Reduction in health inequalities with improved average population health was partly attributable to equal educational opportunities and financial access to care. With the achievement of success during the health transition since World War 2, Japan now needs to tackle major health challenges that are emanating from a rapidly ageing population, causes that are not amenable to health technologies, and the effects of increasing social disparities to sustain the improvement in population health.

Development of a Database of Health Insurance Claims: Standardization of Disease Classifications and Anonymous Record Linkage

Background Health insurance claims (ie, receipts) record patient health care treatments and expenses and, although created for the health care payment system, are potentially useful for research. Combining different types of receipts generated for the same patient would dramatically increase the utility of these receipts. However, technical problems, including standardization of disease names and classifications, and anonymous linkage of individual receipts, must be addressed. Methods In collaboration with health insurance societies, all information from receipts (inpatient, outpatient, and pharmacy) was collected. To standardize disease names and classifications, we developed a computer-aided post-entry standardization method using a disease name dictionary based on International Classification of Diseases (ICD)-10 classifications. We also developed an anonymous linkage system by using an encryption code generated from a combination of hash values and stream ciphers. Using different sets of the original data (data set 1: insurance certificate number, name, and sex; data set 2: insurance certificate number, date of birth, and relationship status), we compared the percentage of successful record matches obtained by using data set 1 to generate key codes with the percentage obtained when both data sets were used. Results The dictionary’s automatic conversion of disease names successfully standardized 98.1% of approximately 2 million new receipts entered into the database. The percentage of anonymous matches was higher for the combined data sets (98.0%) than for data set 1 (88.5%). Conclusions The use of standardized disease classifications and anonymous record linkage substantially contributed to the construction of a large, chronologically organized database of receipts. This database is expected to aid in epidemiologic and health services research using receipt information.

Adult Mortality Attributable to Preventable Risk Factors for Non-Communicable Diseases and Injuries in Japan: A Comparative Risk Assessment

Using a combination of published data and modeling, Nayu Ikeda and colleagues identify tobacco smoking and high blood pressure as major risk factors for death from noncommunicable diseases among adults in Japan.

The Growth Rate of Acoustic Neuromas

Growth rate of acoustic neuromas (AN) was studied in 43 patients. The growth rate was analyzed using tumor increasing size (IS) and tumor volume doubling time (VDT). The growth rate of unilateral AN was lower than that of bilateral AN associated with neurofibromatosis2 (NF2). The growth rate of recurrent tumors was higher than that of non-operative tumors. The relationships between growth rate and age and tumor size were also analyzed. The younger the patient or the greater the tumor size, the higher the growth rate. Several factors, i.e. age and sex of patients, tumor pathology and tumor size, should be considered together for predicting the growth rate on AN.

Stiripentol open study in Japanese patients with Dravet syndrome

Purpose:  To survey the treatment situation of Dravet syndrome in Japan and to compare this result with effectiveness of stiripentol (STP) add‐on therapy in an open‐label multicenter study.

Economic Evaluation of Donepezil Treatment for Alzheimer’s Disease in Japan

To demonstrate the economic impact of donepezil treatment for patients with mild to moderate Alzheimer’s disease (AD) in Japanese clinical settings, we conducted a cost-utility analysis using the Markov model. This analysis was made from a payer’s perspective, and the cost was estimated based on the fee schedule of the Japanese national health insurance and the long-term care insurance. The results of the clinical trial of donepezil on AD in Japan were used to estimate the drug efficacy. Under the base-case analysis with a 2-year time horizon, donepezil treatment for patients with mild to moderate AD was considered to be an economically dominant strategy compared to conventional therapy.

WTP for a QALY and health states: More money for severer health states?

BackgroundIn economic evaluation, cost per quality-adjusted life year (QALY) is generally used as an indicator for cost-effectiveness. Although JPY 5 million to 6 million (USD 60, 000 to 75,000) per QALY is frequently referred to as a threshold in Japan, do all QALYs have the same monetary value?MethodsTo examine the relationship between severity of health status and monetary value of a QALY, we obtained willingness to pay (WTP) values for one additional QALY in eight patterns of health states. We randomly sampled approximately 2,400 respondents from an online panel. To avoid misunderstanding, we randomly allocated respondents to one of 16 questionnaires, with 250 responses expected for each pattern. After respondents were asked whether they wanted to purchase the treatment, double-bounded dichotomous choice method was used to obtain WTP values.ResultsThe results clearly show that the WTP per QALY is higher for worse health states than for better health states. The slope was about JPY −1 million per 0.1 utility score increase. The mean and median WTP values per QALY for 16 health states were JPY 5 million, consistent with our previous survey. For respondents who wanted to purchase the treatment, WTP values were significantly correlated with household income.ConclusionThis survey shows that QALY based on the EQ-5D does not necessarily have the same monetary value. The WTP per QALY should range from JPY 2 million (USD 20,000) to JPY 8 million (USD 80,000), corresponding to the severity of health states.

Estimating a preference-based index from the Japanese SF-36.

OBJECTIVE The main objective of the study was to estimate a preference-based Short Form (SF)-6D index from the SF-36 for Japan and compare it with the UK results. STUDY DESIGN AND SETTING The SF-6D was translated into Japanese. Two hundred and forty-nine health states defined by this version of the SF-6D were then valued by a representative sample of 600 members of the Japanese general population using standard gamble (SG). These health-state values were modeled using classical parametric random-effect methods with individual-level data and ordinary least squares (OLS) on mean health-state values, together with a new nonparametric approach using Bayesian methods of estimation. RESULTS All parametric models estimated on Japanese data were found to perform less well than their UK counterparts in terms of poorer goodness of fit, more inconsistencies, larger prediction errors and bias, and evidence of systematic bias in the predictions. Nonparametric models produce a substantial improvement in out-of-sample predictions. The physical, role, and social dimensions have relatively larger decrements than pain and mental health compared with those in the United Kingdom. CONCLUSION The differences between Japanese and UK valuations of the SF-6D make it important to use the Japanese valuation data set estimated using the nonparametric Bayesian technique presented in this article.

Development and analysis of a nationwide cost database of acute‐care hospitals in Japan

OBJECTIVES Understanding of hospital cost is crucial to achieve an ideal balance between the assurance and improvement of patient safety and quality, and efficient use of finite resources. However, neither a standardized calculation methodology nor a large-scale database of costs in acute-care hospitals exists in Japan. This study aims to develop a standardized methodology, construct a nationwide cost database in Japan, analyse the characteristics of the database and examine the relationship between the cost and the charge from the viewpoint of an appropriate reflection of the cost to the price. METHOD We designed the costing framework, gathered the data for patients discharged from 139 acute-care hospitals in Japan between July 2004 and October 2004 and constructed a database containing information on 284,730 patients. The characteristics of the database and the relationship between the cost and the charge were investigated. RESULTS In the nationwide database we constructed, a wide range in the average cost per hospitalization and average cost per diem was observed. A wide variation of cost components was seen across major diagnostic categories. Moreover, there was a high correlation between the cost and the charge (Correlation coefficient = 0.94). CONCLUSIONS After designing a costing framework, a nationwide database comprised of individual case-level costs with components for acute-care hospitals in Japan was successfully developed. We hope this study contributes to appropriate decision making and helps motivate further research geared towards efficient hospital management and a rational payment system in Japan.

A case for the adoption of pharmacoeconomic guidelines in Japan.

In recent years, more and more Japanese pharmaceutical companies have been submitting pharmacoeconomic data to the government. following the official request that such data may help in setting pharmaceutical prices. The companies have cooperated because. by doing so. they could influence pricing decisions for new products. However, the quality of these data at present is considered to be poor and heavily biased.The introduction of pharmacoeconomic guidelines that outline a set of standardised factors to be included in evaluations are necessary, so that an appropriate comparison of the cost effectiveness of the many new drugs that are introduced into the Japanese market each year can be made. In addition to supporting the development of standardised guidelines, the Ministry of Health and Welfare should clarify how pharmacoeconomic data are to be used to aid policy decisions and also mandate the publication of pharmacoeconomic data.