REVIEW ARTICLE
A review of studies using the Japanese National Database of Health Insurance Claims and Specific Health Checkups
2020 年 2 巻 1 号 p. 13-26
詳細
2020 年 2 巻 1 号 p. 13-26
BACKGROUND
Electronic health databases are increasingly used for research purposes. The Japanese National Database of Health Insurance Claims and Specific Health Checkups (NDB) is a large national administrative claims database. We reviewed published original articles that used the NDB.
METHODS
Studies published from January 2011 to June 2019 using the NDB were identified through PubMed and the academic product lists of the NDB, following the PRISMA guidelines.
RESULTS
68 studies were included in our review (43 were in English and 25 were in Japanese). The first NDB study in English was published in 2015, which was 4 years after the NDB was released for research purposes. The average annual growth rate of the number of NDB studies in English was 237% after the first publication of an NDB study in English. Descriptive studies were the most common study design (n = 42), and the Clinical Medicine was the most common research area (n = 18). The study strength most frequently mentioned by authors of the NDB studies was the large sample size. In terms of limitations, authors most frequently mentioned the lack of important data and validation studies.
CONCLUSIONS
Since its release, the NDB has increasingly attracted attention, and the number of studies using the NDB has grown rapidly. The large sample size and wide array of health care data in the NDB enabled researchers to conduct health service research in various research areas with several study designs. Finally, our review suggests to policy makers that administrative database should be constructed and managed with the environment which promote researchers access to the database and link it to other databases. Although the protection of respondents’ privacy should be carefully considered, higher accessibility and data linkage may maximize the potential of the administrative database and may enable researchers to produce more valuable health service researches for policy making in health care.
Worldwide, electronic health databases are increasingly used for research purposes [1]. Administrative claims databases include real-world data on diagnoses, procedures, and drug prescriptions [2]. The use of real-world data for research has several strengths compared with randomized controlled trials [3]. First, a large population and a variety of data are included in such databases. Second, using real-world data, researchers can conduct studies at lower cost and in a shorter time period [4].
The Japanese National Database of Health Insurance Claims and Specific Health Checkups (NDB) is a large national administrative claims database. The NDB covers more than 126 million people and 1.9 billion electronic claims annually, with data from 99% of the hospitals in Japan [5]. Since the Japanese government publicly released the NDB for research purposes in 2011, the NDB has been used in multiple studies in fields such as health economics, pharmacoepidemiology, and clinical epidemiology, as well as in other types of observational studies. However, no study has yet surveyed NDB studies in terms of the number of published studies, research areas, study designs, strengths, and limitations. We believe that reviewing the studies using the NDB will help policy makers worldwide in constructing and managing their own electronic health databases for the research purposes.
In 1961, Japan achieved universal health insurance [6]. Under this health insurance system, the Ministry of Health, Labour and Welfare (MHLW) launched the NDB in 2009 and started to collect anonymized electronic health insurance claims data for medical and dental services [7]. The NDB can therefore be used to understand the health care process for the population of Japan.
The NDB was publicly released to researchers in 2011. To use the NDB data, study protocols must be approved by the advisory committee of the MHLW. Only researchers in national or local government agencies, universities, and other quasi-public entities can request access to the NDB. Data extracted from the NDB are provided to researchers after information about specific patients and medical facilities has been anonymized. The NDB contains information on patient age, sex, diagnoses, inpatient medical data, outpatient medical data, dental service use, drug prescriptions, and health checkup data. To protect patients’ privacy, researchers are not allowed to link the NDB with other databases. In 2016, the MHLW also began to provide a free-access version of the NDB (NDB Open Data), which anyone can access through the MHLW’s homepage. The NDB Open Data were constructed by aggregating a part of the NDB data without any confidential information [8]; therefore, researchers using the NDB Open Data cannot access patient- or facility-level information.
SEARCH STRATEGY AND SELECTION CRITERIAWe conducted a review according to the PRISMA guidelines [9]. We searched PubMed (from October 2016 to June 2019), Ichushi-Web (A search engine for medical studies in Japanese / from October 2016 to June 2019), and the academic product lists of the NDB reported by the MHLW [8, 10, 11] (MHLW lists) (from January 2011 to June 2019). The MHLW lists are thought be a complete record of all academic products using the NDB data, and the search of PubMed and Ichushi-Web was used to extract studies using the NDB Open Data. Searched term was described in Appendix 1. We also conducted a manual search using the reference lists of the included studies. Exclusion criteria were (1) non-original studies; (2) non-NDB studies. If the authors did not clearly state that they used the NDB, these studies were considered non-NDB studies.
In the screening process, first, two reviewers independently screened the titles and abstracts to apply the exclusion criteria. A full-text review was then conducted, again by two reviewers. Finally, the two reviewers reached agreement regarding the inclusion of each study into this review.
DATA EXTRACTIONWe conducted a narrative review because our aim was not to compare or synthesize any specific statistical indicators among the different studies. Extracted components from the reviewed studies were as follows: (1) study design; (2) research area; (3) setting or sample; (4) outcomes; and (5) strengths and limitations. Study design was categorized as descriptive study, retrospective cohort study, cross-sectional study, or other. For study designs in the “other” category, the name of the study design used in each study was directly used in our review. For the definition of research areas, we used the Science Citation Index subject categories for the journals where the reviewed studies were published [12]. If the journal was not listed in the Science Citation Index, we assigned no categories to the study. In the Science Citation Index, journals are sometimes assigned several subject categories. For journals with multiple similar Science Citation Index subject categories, we selected only one category. We calculated the growth rate for the number of studies published in yeari by dividing the difference between the numbers of studies published in yeari and yeari−1 by the number of studies published in yeari−1. For example, if there were three studies published in 2011 and six studies published in 2012, the growth rate in 2012 was calculated as (6 − 3)/3 = 100%.
After the planned search strategy was carried out, 317 studies were retrieved as screening targets (106 from PubMed, 25 from Ichushi-Web, and 186 from the MHLW list). In the screening process, there were no instances of disagreement between the two reviewers. Ultimately, 68 studies [7, 13–79] were included in our review (43 studies were in English and 25 were in Japanese). Fig. 1 described the screening process and the included studies are listed in Table 1.
MHLW, Ministry of Health, Labour and Welfare; NDB, Japanese National Database of Health Insurance Claims and Specific Health Checkups.
| Title | Topic | Research areas | Study design | Sample/Setting | Outcome |
|---|---|---|---|---|---|
| Variation in fracture risk by season and weather: A comprehensive analysis across age and fracture site using a National Database of Health Insurance Claims in Japan | Variation in fracture risk by season and weather | Endocrinology & Metabolism | Medical Research: Organs & Systems | Clinical Medicine | Retrospective cohort study | 508,051 fractures in Tokyo from April 1, 2013 to March 31, 2016 | Fracture |
| Timely follow-up visits after psychiatric hospitalization and readmission in schizophrenia and bipolar disorder in Japan | Follow-up visits and readmission in patients with schizophrenia or bipolar disorder | Psychiatry | Neurosciences & Behavior | Retrospective cohort study | 48,579 patients aged under 65 years who were admitted to any psychiatric unit from April 2014 to March 2015 | Readmission in patients with schizophrenia or bipolar disorder after discharge |
| Hepatitis B virus reactivation in patients with rheumatoid arthritis: Analysis of the National Database of Japan | Hepatitis B virus reactivation in patients with rheumatoid arthritis | Infectious Diseases | Gastroenterology & Hepatology | Virology | Immunology | Retrospective cohort study | 76,641 patients with rheumatoid arthritis from April 2013 to March 2014 | Hepatitis B virus reactivation |
| Effects of behavioral counseling on cardiometabolic biomarkers: A longitudinal analysis of the Japanese national database | Behavioral counseling on cardiometabolic biomarkers | Medicine: General & Internal | Public, Environmental, & Occupational Health | Social Sciences: General | Retrospective cohort study | 363,440 high-risk persons aged 40–64 who participated in intensive support through Specific Health Guidance for 3 or more months from April 2008 to March 2012 | Body mass index, waist circumference, systolic and diastolic blood pressure, high-density lipoprotein cholesterol, and hemoglobin A1c |
| Preoperative oral care and effect on postoperative complications after major cancer surgery | Preoperative oral care and postoperative complications | Surgery | Medical Research: Diagnosis & Treatment | Clinical Medicine | Retrospective cohort study | 509,179 patients who underwent resection of head or neck for esophageal, gastric, colorectal, lung, or liver cancer from May 2012 to December 2015 | Postoperative pneumonia and all-cause mortality within 30 days of surgery |
| Psychiatric admissions and length of stay during fiscal years 2014 and 2015 in Japan: A retrospective cohort Study using a nationwide claims database | Psychiatric admissions and length of stay | Public, Environmental, & Occupational Health | Medical Research: General Topics | Social Sciences: General | Retrospective cohort study | 605,982 new admissions to psychiatric wards from April 2014 to March 2016 | New psychiatric admissions |
| Glucose and prolactin monitoring in children and adolescents initiating antipsychotic therapy | Glucose and prolactin monitoring with antipsychotic therapy | Pediatrics | Pharmacology & Pharmacy | Psychiatry | Retrospective cohort study | 43,608 patients aged 18 years or younger who were newly prescribed antipsychotics from April 2014 to March 2015 | Use of glucose and prolactin testing through 15 months after drug initiation |
| Association of high psychiatrist staffing with prolonged hospitalization, follow-up visits, and readmission in acute psychiatric units: A retrospective cohort study using a nationwide claims database | The impact of psychiatrist staffing | NA | Retrospective cohort study | 24,678 patients who were newly admitted to acute psychiatric units from October 2014 to September 2015 | Prolonged hospitalization, follow-up visits, and readmission in acute psychiatric units |
| Association of palliative care consultation with reducing inpatient chemotherapy use in elderly patients with cancer in Japan: Analysis using a nationwide administrative database | Palliative care consultation and inpatient chemotherapy use | Health Care Sciences & Services | Clinical Medicine | Retrospective cohort study | 26,012 patients with advanced cancer aged 65 years or older who died | Use of chemotherapy |
| Risk of recurrent overdose associated with prescribing patterns of psychotropic medications after nonfatal overdose | Psychotropic medications and recurrent overdose | NA | Retrospective cohort study | 6,790 patients who were admitted to the hospital because of nonfatal overdose | Admission because of nonfatal overdose |
| Regional variations in in-hospital mortality, care processes, and spending in acute ischemic stroke patients in Japan | Regional variations in in-hospital mortality, care processes, and spending in acute ischemic stroke patients | Peripheral Vascular Diseases | Neurosciences | Retrospective cohort study | 49,400 older adults who were hospitalized for acute ischemic stroke in nine Japanese prefectures from April 2010 to March 2012 | In-hospital mortality, hospital spending, length of stay, tPA utilization rate, regional continuity rate of care planning, rehabilitation for cerebrovascular disease rate, ICU admission rate |
| Fragility fractures in older people in Japan based on the national health insurance claims database | Fragility fractures among older adults | Pharmacology & Pharmacy | Pharmacology & Toxicology | Descriptive study | 490,138 patients aged 65 years or older from May 2013 to September 2014 | Incidence of fragility fractures |
| Regional variance in patterns of prescriptions for chronic kidney disease in Japan | Prescriptions for chronic kidney disease in Japan | Urology & Nephrology | Clinical Medicine | Descriptive study | 567,658,892 prescriptions for chronic kidney disease in 2015 | Prescriptions for chronic kidney disease |
| Epidemiology of adults and children treated for nontuberculous mycobacterial pulmonary disease in Japan | Epidemiology of nontuberculous mycobacterial pulmonary disease | Respiratory System | Clinical Medicine | Descriptive study | 374,603 claims associated with nontuberculous mycobacterial pulmonary disease from 2009 to 2014 | Nontuberculous mycobacterial pulmonary disease |
| Estimates of hip fracture incidence in Japan using the National Health Insurance Claim Database in 2012–2015 | Estimates of hip fracture incidence | Endocrinology & Metabolism | Clinical Medicine | Descriptive study | 119,809 hip fracture from 2012 to 2015 | Number of hip fractures, number of osteoporosis prescriptions, bone turnover marker level, and bone mineral density |
| Targets for optimizing oral antibiotic prescriptions for pediatric outpatients in Japan | Oral antimicrobial prescriptions for pediatric outpatients | Infectious Diseases | Immunology | Descriptive study | 132,869,332 oral antimicrobial prescriptions for children aged under 16 years in three urban districts in Japan from January 2013 to December 2016 | Pattern of oral antimicrobial prescription |
| Nationwide survey of indications for oral antimicrobial prescription for pediatric patients from 2013 to 2016 in Japan | Oral antimicrobial prescriptions for pediatric patients | Infectious Diseases | Pharmacology & Pharmacy | Pharmacology & Toxicology | Descriptive study | 297,197,328 infectious disease-related visits among children in Japan aged 15 years or younger from 2013 to 2016 | Antimicrobial prescriptions for pediatric patients |
| Inpatient expenditures attributable to hospital-onset clostridium difficile infection: A nationwide case–control study in Japan | Inpatient expenditures attributable to hospital-onset clostridium difficile infection | Health Care Sciences & Services | Pharmacology & Pharmacy | Health Policy & Services | Economics | Pharmacology & Toxicology | Descriptive study | 39,670 cases of hospital-onset clostridium difficile infection from April 2010 to December 2016 | Inpatient expenditures and length of stay for hospital-onset clostridium difficile infection in all health care institutions providing inpatient care |
| Wide difference in biologics usage and expenditure for the treatment of patients with rheumatoid arthritis in each prefecture in Japan analyzed using “National Database of Health Insurance Claims and Specific Health Checkups of Japan” | Biologics usage and expenditure for the treatment of patients with rheumatoid arthritis | Rheumatology | Clinical Medicine | Medical Research: Organs & Systems | Descriptive study | Data on the top 30 most frequently prescribed biologics for rheumatoid arthritis from April 2014 to March 2015 | Biologics prescription for rheumatoid arthritis |
| Trends in isolated meniscus repair and meniscectomy in Japan, 2011–2016 | Trends in isolated meniscus repair and meniscectomy | Orthopedics | Orthopedics, Rehabilitation, & Sports Medicine | Clinical Medicine | Descriptive study | 34,966 meniscus surgeries in 2015 | Number of meniscus surgeries and meniscus repair ratio |
| Severe abnormal behavior incidence after administration of neuraminidase inhibitors using the national database of medical claims | Abnormal behavior after neuraminidase inhibitors | Infectious Diseases | Clinical Medicine | Descriptive study | 13,943,957 influenza patients from 201 to 2014 | Number of abnormal behaviors after the prescription of neuraminidase inhibitors |
| Comparative study of preciseness in the regional variation of influenza in Japan among the National Official Sentinel Surveillance of Infectious Diseases and the National Database of Electronic Medical Claims | Regional variation in influenza | Biology | Descriptive study | Influenza incidence data from 2010 to 2014 | Incidence of Influenza |
| Nationwide survey of severe postpartum hemorrhage in Japan: An exploratory study using the national database of health insurance claims | Epidemiology of severe postpartum hemorrhage | Obstetrics & Gynecology | Clinical Medicine | Reproductive Medicine | Descriptive study | 126 cases of severe postpartum hemorrhage from 2011 to 2014 | Trend of blood transfusion |
| Estimation of total prescription weights of active pharmaceutical ingredients in human medicines based on a public database for environmental risk assessment in Japan | Estimation of total prescription of active pharmaceutical ingredients | Medicine: Legal | Pharmacology & Pharmacy | Toxicology | Descriptive study | 2,058 active pharmaceutical ingredients from 2014 to 2016 | Distribution of active pharmaceutical ingredients |
| Regional clinical practice variation in urology: Usage example of the Open Data of the National Database of Health Insurance Claims and Specific Health Checkups of Japan | Variation in regional clinical practice in urology | Urology & Nephrology | Clinical Medicine | Descriptive study | 19,691 urological surgical procedures from 2015 to 2016 | Distribution of urological surgical procedures |
| Rationale and descriptive analysis of Specific Health Guidance: The Nationwide Lifestyle Intervention Program targeting metabolic syndrome in Japan | The impact of Specific Health Guidance | Peripheral Vascular Diseases | Clinical Medicine | Cardiovascular & Respiratory Systems | Descriptive study | 89,014 patients eligible for intensive health guidance and 132,502 patients eligible for motivational health guidance | Changes in waist circumference, body mass index, and other MetS risk factors |
| Dissemination of cognitive behavioral therapy for mood disorder under the national health insurance scheme in Japan: A descriptive study using the National Database of Health Insurance Claims of Japan with special focus on Japan’s southwest region | Dissemination of cognitive behavioral therapy for mood disorder | NA | Descriptive study | 60,304 patients who received 256,423 CBT sessions recorded in the database from 2010 to 2015 | Trend in the use of cognitive therapy/cognitive behavioral therapy for mood disorders |
| Thyroid function tests before prescribing anti-dementia drugs: A retrospective observational study | Thyroid function tests before prescribing anti-dementia drugs | NA | Descriptive study | 262,279 patients aged 65 years or older who were newly prescribed anti-dementia drugs from April 2015 to March 2016 | Percentage of patients receiving thyroid function tests before the initiation of anti-dementia drug treatment |
| The survey of the compliance situation to the antihypertensive therapy guideline by analyzing Japanese national claims data | Compliance to the antihypertensive therapy guideline | Pharmacology & Pharmacy | Pharmacology & Toxicology | Descriptive study | 26,186 inpatients and 155,839 outpatients who received antihypertensive therapy in October 2011 | Antihypertensive prescription patterns in patients with ischemic heart disease-related conditions and KD |
| Cost analysis of transplantation in Japan, performed with the use of the National Database | Cost of transplantation | Surgery | Immunology | Transplantation | Medical Research: Diagnosis & Treatment | Clinical Medicine | Descriptive study | 1,811 patients who underwent transplantation from April 2009 to March 2010 | Cost of transplantation |
| Epidemiology of overdose episodes from the period prior to hospitalization for drug poisoning until discharge in Japan: An exploratory descriptive study using a nationwide claims database | Epidemiology of overdose admission | Public, Environmental, & Occupational Health | Medical Research: General Topics | Social Sciences: General | Descriptive study | 21,663 episodes of overdose admission from October 2012 to September 2013 | Admission because of overdose |
| The first report of Japanese antimicrobial use measured by national database based on health insurance claims data (2011–2013): Comparison with sales data, and trend analysis stratified by antimicrobial category and age group | Trend of antimicrobial use | Infectious Diseases | Immunology | Descriptive study | Prescriptions for antimicrobial use from 2011 to 2013 | Total antimicrobial use |
| Estimation of the number of children with cerebral palsy using nationwide health insurance claims data in Japan | Estimation of the number of children with cerebral palsy | Pediatrics | Clinical Neurology | Neuroscience & Behavior | Descriptive study | 44,381 children and young adults aged 20 years or younger who had received a CP diagnosis | Number of children diagnosed with CP |
| Evaluation of estimated number of influenza patients from national sentinel surveillance using the national database of electronic medical claims | Evaluation of the estimated number of influenza patients | Infectious Diseases | Immunology | Descriptive study | Patients with influenza | Number of patients with influenza |
| The effectiveness of risk communication regarding drug safety information: A nationwide survey by the Japanese public health insurance claims data | Risk communication regarding drug safety information | Pharmacology & Pharmacy | Pharmacology & Toxicology | Descriptive study | 4,933,481 patients with rheumatoid arthritis from January 2010 to June 2010 | Implementation of the hepatitis virus-monitoring test |
| Epidemiology of psoriasis and palmoplantar pustulosis: A nationwide study using the Japanese national claims database | Epidemiology of psoriasis and palmoplantar pustulosis | Medicine: General & Internal | Clinical Medicine | Descriptive study | 565,903 patients with psoriasis or palmoplantar pustulosis from April 2010 to March 2011 | Prevalence of psoriasis and palmoplantar pustulosis |
| Association of severe abnormal behavior and acetaminophen with/without neuraminidase inhibitors | Abnormal behavior and acetaminophen with/without neuraminidase inhibitors | Infectious Diseases | Clinical Medicine | Cross-sectional study | 28,532,927 patients with influenza from September 2009 to March 2016 | Severe abnormal behavior after the prescription of acetaminophen |
| Cesarean section rates and local resources for perinatal care in Japan: A nationwide ecological study using the national database of health insurance claims | Epidemiology of cesarean section | Obstetrics & Gynecology | Reproductive Medicine | Clinical Medicine | Cross-sectional study | 190,361 cesarean deliveries in 2013 | Rate of cesarean section |
| Patterns of CT use in Japan, 2014: A nationwide cross-sectional study | Patterns of CT use | Clinical Medicine | Radiology, Nuclear Medicine, & Imaging | Cross-sectional study | 28.1 million CT scans from April 2014 to March 2015 | Rate of CT examinations per 1000 population |
| Polypharmacy of medications and fall-related fractures in older people in Japan: A comparison between driving-prohibited and driving-cautioned medications | Polypharmacy and fall-related fractures | Pharmacology & Pharmacy | Pharmacology & Toxicology | Cross-sectional study | 629,530 outpatients aged 65 years or older receiving driving-prohibited or driving cautioned medications | Occurrence of fall-related fractures |
| Cost-minimization analysis of deep-brain stimulation using national database of Japanese health insurance claims | Cost of deep-brain stimulation | Medicine: Research & Experimental | Clinical Neurology | Neuroscience & Behavior | Cross-sectional study | 519 cases undergoing dual-channel deep-brain stimulation implantation surgery from March 2009 to December 2015 | Costs of dual-channel deep-brain stimulation |
| High incidence of diabetes in people with extremely high high-density lipoprotein cholesterol: Results of the Kanagawa Investigation of Total Checkup Data from the National Database-1 (KITCHEN-1) | Diabetes in people with extremely high high-density lipoprotein cholesterol | Medicine: General & Internal | Clinical Medicine | Retrospective cohort study | 387,642 patients aged 40 to 68 years without diabetes from April 2008 to March 2009 and from April 2014 to March 2015 | Incidence of diabetes |
| National burden of the pharmaceutical cost of wet compresses and its cost predictors: Nationwide cross-sectional study in Japan | Pharmaceutical cost of wet compresses | Health Policy & Services | Economics | Social Sciences: General | Descriptive study | Pharmaceutical cost of wet compresses in 2015 | Pharmaceutical cost of wet compresses |
| [Cardiovascular or cerebrovascular disease and risk factors of them in Shimane Prefecture: using the data of Specific Health Checkups] (Japanese) | Cardiovascular or cerebrovascular disease | NA | Descriptive study | 149,238 people who tool Specific Health Checkups in Shimane prefecture in 2014 | Cardiovascular or cerebrovascular disease and risk factors of them |
| [Factors associated with the disparity of life expectancy among Japanese prefectures: using the National Database of Health Insurance Claims and Specific Health Checkups] (Japanese) | Life expectancy and its risk factors | NA | Cross-sectional study | 47 prefectures in Japan in 2015 | Life expectancy |
| [Association between osteoporotic fractures and care need status] (Japanese) | Current status of health checkup for osteoporosis | NA | Cross-sectional study | 304,535 people in Japan who took health checkup for osteoporosis in 2015 | Osteoporosis |
| [A comprehensive survey of clinical practice concerning telemedicine treatment] (Japanese) | Medical activities related to telemedicine | NA | Descriptive study | 50 medical activities related to telemedicine in 2018 | Telemedicine |
| [Comparison of smoking status among 47 prefectures in Japan] (Japanese) | Smoking status in Japan | NA | Descriptive study | 47 prefectures in Japan in 2017 | Smoking rate |
| [Survey of Prescription Volume and Adverse Events of NSAIDs Patches in Fiscal Year 2015] (Japanese) | Prescription volume and adverse events of NSAIDs patches | NA | Descriptive study | 47 prefectures in Japan in 2017 | Adverse events of NSAIDs patches |
| [Relationship between the Number of Adult Obesity and Neuropsychiatric Prescription Drugs] (Japanese) | Association between adult obesity and neuropsychiatric prescription drugs | NA | Cross-sectional study | Obesity population in 47 prefectures in Japan in 2016 | The number of neuropsychiatric prescription drugs |
| [Appropriate arrangement of acute myocardial infarction care facilities: using DPC and NDB databases] (Japanese) | Association between accumulation of care facilities and treatment performance | NA | Cross-sectional study | Multiple secondary medical areas in Japan in 2013 | Gini coefficient of the acute myocardial infarction care facilities |
| [Considering community “recovery” from hospital discharge rate and re-hospitalization rate] (Japanese) | Recovery from hospital discharge rate and re-hospitalization in patients with psychiatric diseases | NA | Descriptive study | 344 secondary medical areas in Japan from March 2016 to March 2017 | Hospitalization status for psychiatric diseases |
| [Association between Number of Teeth and Medical Visit due to Aspiration Pneumonia in Older People Using the Receipt and Health Checkup Information Database] (Japanese) | Association between number of teeth and medical visit due to aspiration pneumonia in older people | NA | Cross-sectional study | 1,662,158 older patients with periodontitis and 356,662 older patients with loss of teeth in 2013 | Aspiration pneumonia |
| [Survey of lifestyle diseases in Gifu prefecture: using the Specific Health Checkups] (Japanese) | Distribution of patients with lifestyle diseases | NA | Descriptive study | Gifu prefecture in Japan in 2013 | Percentage and distribution of patients with lifestyle diseases |
| [Actual use of direct oral anticoagulant (DOAC) in fiscal year 2014: using the national database of health insurance claims and specific health checkups of Japan (NDB) open data] (Japanese) | Prescription of DOAC | NA | Descriptive study | 188,634,206 prescription days of DOAC in 2014 | Total prescription days of DOAC |
| [Surveillance to Determine Adverse Reactions to Carbamazepine and Lamotrigine: Analysis of the “Japanese Adverse Drug Event Report”, “Information on Adverse Reaction Relief Benefits”, and “Health Insurance Claims and Specific Health Checkups of Japan” Databases] (Japanese) | The status of actual adverse reactions to carbamazepine and lamotrigine | NA | Descriptive study | 47 prefectures in Japan from 2012 April to March 2016 | Adverse reactions to carbamazepine and lamotrigine |
| [Status of the hospitalization of children: using the National Database of Health Insurance Claims and Specific Health Checkups] (Japanese) | Status of the hospitalization of children | NA | Descriptive study | 47 prefectures in Japan in 2014 | The number of patients and hospitalization days in pediatric department |
| [Association between the number of teeth and health expenditures in medicine or dentistry: using the National Database of Health Insurance Claims and Specific Health Checkups] (Japanese) | Association between the number of teeth and health expenditures in medicine or dentistry | NA | Cross-sectional study | 2,231,983 patients aged ≧ 40 who had periodontitis in 2013 | Health expenditures in medicine or dentistry |
| [Study on Risk of Gastrointestinal Complications in Low-dose Aspirin Therapy Using the National Receipt Database] (Japanese) | Effect of low-dose aspirin on gastrointestinal complications | NA | Descriptive study | 4,591,296 patients who received low-dose aspirin therapy in 2010 | Gastrointestinal diseases |
| [Survey of Usage of Medication with Driving with Prohibition or Caution by the National Health Insurance Claims Database in Japan] (Japanese) | Usage status of medications with driving with prohibitions or cautions | NA | Descriptive study | 657,345 patients aged ≧ 25 who were administered medications with driving with prohibitions or cautions in October 2011 | Medications with driving with prohibitions or cautions |
| [Antipsychotics prescribing patterns of patients with schizophrenia in Japan: Using the National Database of Health Insurance Claims Information and Specified Medical Checkups] (Japanese) | Prescription pattern of antipsychotics for patients with schizophrenia | NA | Descriptive study | 47 prefectures in Japan in October 2011 | Appropriate prescription of antipsychotics |
| [Actual status of prescription patterns of anxiolytics and hypnotics in outpatients using National Database of Health Insurance Claim Information and Specific Medical Checkups] (Japanese) | Prescription patterns of anxiolytics and hypnotics in outpatients | NA | Descriptive study | 32,968 patients who received psychiatric outpatients’ consultations in October 2011 | Prescription patterns of anxiolytics and hypnotics in outpatients |
| [Same Examinations in Different Healthcare Providers in the Same Month of Referral, Analysis by Reimbursement Claim Database] (Japanese) | Same Examinations in Different Healthcare Providers in the Same Month of Referral | NA | Descriptive study | 755,247 patients in October 2011 | Same Examinations in Different Healthcare Providers in the Same Month of Referral |
| [Drug Utilization Study of Potential Drug-drug Interactions using the Sampling Dataset of the National Database of Health Insurance Claim Information] (Japanese) | Prescription pattern of prohibited concomitant medications | NA | Descriptive study | 431,873 patients who were prescribed for any drugs in October 2011 | Prescription of prohibited concomitant medications |
| [Association of Antipsychotic Use with Extrapyramidal Symptoms: Data Mining of the Japanese National Insurance Claims Database] (Japanese) | Effect of antipsychotic use on extrapyramidal symptoms | NA | Descriptive study | 47 prefectures in Japan from January 2010 to December 2012 | Extrapyramidal symptoms |
| [Characteristics of heat-illness patients in Japan: Analysis from receipt data for the past 5 years] (Japanese) | Trend of patients with heat-illness | NA | Descriptive study | 1,644,527 from 2010 to 2014 | Heat-illness |
| [A Preliminary Survey to Measure the Quality Indicators of End-of-life Cancer Care Using the Japanese National Database] (Japanese) | Measurement of the quality indicators of end-of-life cancer care | NA | Descriptive study | 1,233 patients who died of cancer in October 2012 | Life-sustaining treatment and chemotherapy near the time of death |
| [Study on the Risk Factors for Postoperative Delirium Using the National Health Insurance Claims Database in Japan] (Japanese) | Risk factors for postoperative delirium | NA | Cross-sectional study | 575,469 patients who emerged from postoperative delirium from August 2015 to August 2016 | Postoperative delirium |
NA, not applicable; tPA, tissue plasminogen activator; ICU, intensive care unit; MetS, metabolic syndrome; CBT, cognitive therapy/cognitive behavioral therapy; KD, kidney disease; CP, cerebral palsy; CT, computed tomography.
The first NDB study was published in 2013, 2 years after the MHLW began to release the NDB data. Limited to English studies, the first NDB study was published in 2015. The numbers of published studies were 2, 3, 6, 4, 12, 28 and 13 in 2013, 2014, 2015, 2016, 2017, 2018, and January to June of 2019, respectively. The average annual growth rate since the first publication of the NDB studies was 90% (for all studies) from 2013 to 2018 and 237% (for only English studies) from 2015 to 2018. The cumulative number of NDB studies published since the initial release of the NDB is illustrated in Fig. 2.
NDB, Japanese National Database of Health Insurance Claims and Specific Health Checkups.
In terms of study design, 42 of the included studies were descriptive studies, 12 were retrospective cohort studies, and 14 were cross-sectional studies. The five most frequently observed research areas were Clinical Medicine (n = 18), Pharmacology & Pharmacy (n = 8), Infectious Diseases (n = 7), Pharmacology & Toxicology (n = 6), and Immunology (n = 5). In total, 36 research areas were observed among the reviewed studies. Table 2 describes the top eight research areas in terms of the number of NDB studies.
| Research area | Number of studies |
|---|---|
| Clinical Medicine | 18 |
| Pharmacology & Pharmacy | 8 |
| Infectious Diseases | 7 |
| Pharmacology & Toxicology | 6 |
| Immunology | 5 |
| Neuroscience & Behavior | 4 |
| Social Sciences: General | 4 |
| Public, Environmental, & Occupational Health | 3 |
| Medicine: General & Internal | 3 |
NDB, Japanese National Database of Health Insurance Claims and Specific Health Checkups.
The most frequently mentioned strength of the NDB studies was the large cohort, which covers almost all health insurance claims in Japan. The authors also mentioned several limitations of the NDB, such as the lack of access to important data, the unclear validity of the data coding, and the difficulty of making causal inferences with retrospective collected data.
The NDB has been used widely by researchers in Japan. However, no previous study had investigated the growth and trends in published studies using the NDB. Our review showed that the number of studies using the NDB remains small but that it has increased remarkably since the initial release of the NDB study.
There are fewer studies using the NDB, compared with the numbers of studies using other countries’ administrative claims databases. Compared with the 68 NDB studies published from 2011 to 2019, the total number of studies using administrative claims databases in other countries were much higher: 749 in the United Kingdom from 1995 to 2009 [80], 383 in Taiwan from 2000 to 2009 [81], 70 in Germany from 1998 to 2007 [82], 110 in France from 1988 to 2009 [83], and 325 in Canada from 1969 to 2004 [84]. However, the present review showed that the NDB studies had a higher average annual growth rate (237% in English and 90% in English and Japanese), compared with the growth rates of studies using other countries’ administrative claims databases. The average annual growth rate has been reported as 45.8% for Taiwan [81] and 53.3% for the United Kingdom [80]. The first NDB study in English were published in the first 4 years after the release of the NDB data for research purposes. This lower publication status of NDB studies may be explained by the limited accessibility of the NDB. A previous study evaluated the accessibility of administrative healthcare databases in the Asia-Pacific countries [85]. They scored database accessibility on a seven-point scale, assigning a “level two” score to the NDB, which was the second-lowest score reported. As explained above, the MHLW grants access to the NDB only to researchers belonging to specific organizations. Moreover, to use the NDB, researchers must prepare a high-level security system for data management in their laboratory or use the data only at the on-site research center. These security system requirements may limit access to the NDB.
However, high accessibility does not necessarily benefit researchers and patients. Releasing electronic health data without sufficient security could threaten respondents’ privacy [86], causing clear ethical problems. Therefore, the trade-off between accessibility and the protection of respondents’ privacy should be carefully considered when making decisions regarding the provision of electronic health data. Training on data handling may improve the accessibility of the database while safeguarding respondents’ privacy. For example, in the United States, the Research Data Assistance Center provides training and tutorials on using the Medicare dataset through their homepage and on-site [87].
Our study showed that the NDB has been used in a variety of research areas using multiple study designs. The two most common research areas for the reviewed NDB studies were Clinical Medicine and Pharmacology & Pharmacy. Globally, both of these areas are major research areas in electronic health database research, and 69.4% of the reviewed NDB studies were in one of these two areas.
We also found several unique research areas that have not been reported for other countries’ electronic health database studies. These included Infectious Diseases, Immunology, and Neuroscience & Behavior [80, 81]. In terms of study design, descriptive studies were the most frequently observed type of research among the NDB studies. This may be because the representativeness and comprehensiveness of the NDB motivated researchers to establish population-based evidence using the NDB.
Like other national administrative claims databases, the most distinctive strength of the NDB was its large sample size across all age groups, which gives higher generalizability and statistical stability to the study. The sample or setting in Table 1 showed that a large number of patients, disease onsets, or medical activities were included in each NDB studies. Among the major national administrative claims databases worldwide, the NDB has a relatively large sample size of 126 million people and 1.9 billion claims annually, with data from 99% of the hospitals in Japan. The population coverage in other national administrative claims databases was as follows: 342 million annual claims in Taiwan [81], 56.3 million people in the United States (Medicaid) [88], 6% of the population in the United Kingdom [89], 70.3 million people in Germany [90], 66 million people in France [91], and 50 million people in South Korea [92]. The NDB also had the strength of wide array of health care data which were shown in the sample or setting or outcome in Table 1. Within the health insurance services, we can get almost all data of diagnosis, prescriptions, or surgeries in patient-level. This various items in the NDB potentially enables researchers to conduct diverse health service researches which may produce valuable policy recommendations for policy makers.
Several limitations of the NDB were also reported in the reviewed studies. The most frequently reported limitation was a lack of important information such as disease severity, financial or educational status, family history, and other variables. A lack of important information may cause confounding in the research results. This limitation could be resolved by linking the NDB to other databases. Although linking data between the NDB and other databases has not been allowed [93], the Japanese government plans to link the NDB to the long-term care insurance claims data [94]. This may enable researchers to obtain important information that are not available from the NDB alone.
The absence of validation studies was also mentioned as a limitation of the NDB. A previous study systematically reviewed validation studies for health claims databases in the Asia-Pacific region [95]. In this previous review, no validation studies were found for the NDB, in contrast to 21 such studies in Australia, 7 in Taiwan, and 6 in South Korea. To facilitate validation studies, national administrative claims databases should be linked to other databases such as electronic medical records. For example, in the United Kingdom, after the government allowed researchers to link the electronic health database to other databases [80], 357 validation studies were conducted from 1987 to 2008 [89].
The present study had a limitation. This review was conducted only 4 years after the first NDB study appeared. Given the higher average annual growth rate of the number of NDB studies, we might underestimate the growing trend of the NDB studies.
Since its release, the NDB has increasingly attracted attention, and the number of studies using the NDB has grown rapidly. The large sample size and wide array of health care data in the NDB enabled researchers to conduct health service research in various areas with several study designs. Finally, our review suggests to policy makers that the administrative database should be constructed and managed with the environment which promote researchers to access to the database and to link the database to other databases. Although the protection of respondents’ privacy should be carefully considered, higher accessibility and data linkage may maximize the potential of the administrative database and may enable researchers to produce more valuable health service researches for policy making in health care.
This work was supported by grants from the Ministry of Health, Labour and Welfare, Japan (19AA2007 and H30-Policy-Designated-004) and the Ministry of Education, Culture, Sports, Science and Technology, Japan (17H04141). The supporting agencies only provided grant support. They were not involved in conducting the research.
The authors declare that they have no conflicts of interest.
| Searched term for English studies: (“national claims database” OR “national health insurance claims database” OR “national database” OR “national insurance claims database” OR nationwide health insurance claims data) AND “Japan” |
| Searched term for Japanese studies: (NDB OR レセプト情報・特定健診等情報データベース OR ナショナルデータベース) AND (language = Japanese, original article, except for case reports) |
