BACKGROUND

In atrial-fibrillation (AF)-related acute ischemic stroke (AIS), the optimal timing for starting or resuming non-vitamin K antagonist oral anticoagulants (NOAC) remains unknown. We aimed to determine the optimal timing of NOAC initiation for AF-related AIS using the Japanese Diagnosis Procedure Combination inpatient database.

METHODS

We retrospectively collected data of adult inpatients who were admitted with a diagnosis of AF-related AIS from July 2010 to March 2016. Patients were divided into tertiles of hospital days for initiating NOAC (early, delayed, and late groups). Incidence of hemorrhagic events or NOAC discontinuation was the primary outcome. Secondary outcome included in-hospital death, any hemorrhagic event, thrombotic events, and deterioration of modified Rankin scale from admission to discharge. Logistic regression analyses were performed to compare the primary and secondary outcomes among the three groups with adjustments for patient backgrounds using inverse probability of treatment weighting by propensity score analysis.

RESULTS

We identified 55,289 eligible patients, including 17,810 in the early group (3–5 days), 18,473 in the delayed group (6–10 days), and 19,006 in the late group (≥11 days). Logistic regression analyses indicated the odds ratio for the primary outcome in the late group was not significant (adjusted odds ratio, 1.08; 95% confidence interval, 1.0–1.16).

CONCLUSIONS

NOAC initiation within 3–5 days was safer and associated with the lower proportions of the secondary outcomes in patients with AF-related AIS.

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.

BACKGROUND

The development and expanding accessibility of large-scale medical databases support increasing use of these databases for clinical epidemiological studies in Japan.

METHODS

Members of the Database Utilization Committee of the Society of Clinical Epidemiology discussed the ways to enhance scientific rigor in the utilization of large-scale medical databases in Japan. The topics covered included what we need to know about the current research environment when conducting large-scale medical database studies, the key points to consider when conducting clinical research using these databases, and the use of real-world evidence in regulatory decision making.

RESULTS

In generating real-world evidence, several evaluation principles should be noted: the characteristics of data commonly used for clinical epidemiology in Japan; the need for reproducibility and transparency in database studies; the development of research questions for database studies; the need to assess the quality and validity of data; and legal and ethical considerations. We also introduce the discussions on real-world evidence for drug approval applications.

CONCLUSION

With rapid technological developments, the characteristics of medical databases and analytical methods will evolve over time. Keeping these principles in mind, we must continuously update the evaluation methods and strategies used to assess the data.