Japanese Journal of Health and Research
Online ISSN : 2434-8481
Print ISSN : 2432-602X
ISSN-L : 2432-602X
The need and key points for patient matching in clinical studies using the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB)
Shinichiro KuboTatsuya NodaTomoya MyojinTsuneyuki HigashinoHiroki MatsuiGenta KatoTomoaki Imamura
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JOURNAL FREE ACCESS

2017 Volume 38 Pages 11-19

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Abstract

[Background]

The National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) contains monthly claims for reimbursement of medical expenses and is managed by two types of personal identification (IDs) of a patient. Errors occur in linking the information of two IDs to a patient (patient matching). In this study, we summarize important points to identify.

[Methods]

The 2013 NDB data were used to identify errors that interfere with patient matching and to reveal the number and frequency of such errors.

[Results]

Both ID information include life event-related changes, such as an insurance provider’s ID number, employer, employee (patient) career changes, retirement, and a patient’s name change due to marriage. In addition, different patients are often identified as the same patient, which is called as Type I errors, such as persons who have same surnames, given names and birthdays, and twins who are dependents with the same surname. Furthermore, variations in writing used at different healthcare providers and even typos when computerizing potentially identify one patient as different individuals (Type II errors). Our 1-year follow-up study revealed that changes in the IDs occur in approximately 11% of patients; hence, these patients are usually excluded from cohort studies. Type I and II errors also occurred simultaneously in approximately 0.8% of patients, suggesting that an estimated 1% of patients may be difficult to follow-up.

[Conclusion]

Problems with patient matching include life event-related changes in patient IDs used in the NDB and insufficiency of key variables in patient matching. A cohort of patients with different names, regardless of anonymity, may be used as training data to investigate the accuracy of matching. Further study is needed to improve the patient matching system used in the NDB.

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© 2017 Japan Health & Research Institute
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