Existing Data Sources for Clinical Epidemiology: Database of the National Hospital Organization in Japan

Figures & data

Figure 1 Distribution of 140 hospitals in the National Hospital Organization all over Japan. The locations of some representative million cities are also indicated on the map.

Table 1 Patient Demographic in NHO Database

	NHO Database Year 2010–2019 N (%)	NHO Database Year 2017 N (%)	Patient Survey 2017^† N (%)
Total patients	8,341,977	2,098,183	63,727,000
Men	3,944,721 (47.3%)	973,923 (46.4%)	26,645,000 (41.9%)
Women	4,397,256 (52.7%)	1,124,260 (53.6%)	36,918,000 (58.1%)
Age in 2017
<19	–	292,588 (13.9%)	4,960,000 (7.8%)
19–39	–	225,913 (10.8%)	5,677,000 (8.9%)
40–74	–	1,006,392 (48.0%)	32,221,000 (50.6%)
75 and more	–	573,290 (27.3%)	20,869,000 (32.7%)
Major diseases
Ischemic heart diseases	581,988 (7.0%)	155,459 (7.4%)	722,000 (1.1%)
Cerebrovascular diseases	543,665 (6.5%)	153,961 (7.3%)	1,115,000 (1.7%)
Malignant neoplasms	925,934 (11.1%)	317,025 (15.1%)	1,782,000 (2.8%)
Diabetes mellitus	939,548 (11.3%)	303,010 (14.4%)	3,289,000 (5.2%)
Dementia	257,454 (3.1%)	57,551 (2.7%)	704,000 (1.1%)

Notes: ^†The Patient Survey 2017 by the Ministry of Health, Labour and Welfare in Japan results publish the number of patients rounded to the nearest thousand.

Table 2 Summary of Data Collected in NHO Database

Category	Data Element
Facility information	Number of beds, Address, Facility type etc.
Patient profile	Gender, Birth date, Height, Weight, Activity of daily living, Address, Postal code, etc.
Hospitalization	Date of hospital admission and discharge, Outcome, Admission path, Discharge destination, Ambulance transport, etc.
Diagnosis	Onset date, disease name and codes based on ICD-10 and Japanese insurance claim: Main disease, Disease triggering admission, Comorbidity at hospital admission, Complications among hospitalization, Most and Second most resource-using disease
Severity of diseases	JCS, mRS, SOFA score, A-DROP scoring system^†, Killip classification, etc.
Medical practice	Procedures, Medications, Surgeries, Rehabilitation etc. with date of creation and performed, quantity, cost, and duration, etc.
Meal	Date and content
Examination	Laboratory test, Blood pressure, Heart rate, Body temperature, Respiratory rate, Oxygen saturation, etc.
Medical chart	Chart by physician and nurse, discharge summary

Notes: ^†A-DROP scoring system is a modified version of CURB-65 developed by the Japanese Respiratory Society^38,39.

Abbreviations: ICD-10, International Statistical Classification of Diseases and Related Health Problems 10th Revision; JCS, Japan Coma Scale; mRS, Modified-Rankin Scale; SOFA, sequential Organ Failure Assessment score.

Figure 2 Comparison of age distribution of patients between Patient Survey 2017 and NHO database in 2017 among the five major diseases: (A) Ischemic heart diseases, (B) Cerebrovascular diseases, (C) Malignant neoplasms, (D) Diabetes mellitus, (E) Dementia.

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