Table 1. The number of published articles in the four databases between 2010 and 2021.
| NDB, n (%) | NDB Open Data, n (%) | JMDC, n (%) | DPC, n (%) | All, n (%) | |
|---|---|---|---|---|---|
| All | 95 | 31 | 222 | 699 | 1047 |
| Internal medicine | 49 (51.6) | 12 (38.7) | 144 (64.9) | 195 (27.9) | 400 (38.2) |
| Pediatrics | 3 (3.2) | 1 (3.2) | 12 (5.4) | 43 (6.2) | 59 (5.6) |
| Dermatology | 1 (1.1) | 1 (3.2) | 4 (1.8) | 3 (0.4) | 9 (0.9) |
| Psychiatry | 12 (12.6) | 1 (3.2) | 17 (7.7) | 12 (1.7) | 42 (4.0) |
| Surgery | 3 (3.2) | 1 (3.2) | 0 0.0 | 134 (19.2) | 138 (13.2) |
| Orthopedics | 7 (7.4) | 5 (16.1) | 6 (2.7) | 56 (8.0) | 74 (7.1) |
| Obstetrics and gynecology | 5 (5.3) | 2 (6.5) | 7 (3.2) | 14 (2.0) | 28 (2.7) |
| Ophthalmology | 3 (3.2) | 1 (3.2) | 14 (6.3) | 4 (0.6) | 22 (2.1) |
| Otolaryngology | 0 0.0 | 0 0.0 | 3 (1.4) | 13 (1.9) | 16 (1.5) |
| Urology | 0 0.0 | 1 (3.2) | 2 (0.9) | 21 (3.0) | 24 (2.3) |
| Neurosurgery | 1 (1.1) | 0 0.0 | 2 (0.9) | 43 (6.2) | 46 (4.4) |
| Radiology | 0 0.0 | 1 (3.2) | 0 0.0 | 3 (0.4) | 4 (0.4) |
| Anesthesiology | 0 0.0 | 0 0.0 | 0 0.0 | 13 (1.9) | 13 (1.2) |
| Pathology | 0 0.0 | 0 0.0 | 0 0.0 | 0 0.0 | 0 0.0 |
| Clinical laboratory | 0 0.0 | 0 0.0 | 0 0.0 | 0 0.0 | 0 0.0 |
| Emergency medicine | 0 0.0 | 0 0.0 | 2 (0.9) | 98 (14.0) | 100 (9.6) |
| Plastic surgery | 0 0.0 | 0 0.0 | 0 0.0 | 3 (0.4) | 3 (0.3) |
| Rehabilitation | 4 (4.2) | 2 (6.5) | 2 (0.9) | 24 (3.4) | 32 (3.1) |
| General medicine | 4 (4.2) | 0 0.0 | 2 (0.9) | 13 (1.9) | 19 (1.8) |
| Other | 3 (3.2) | 3 (9.7) | 5 (2.3) | 7 (1.0) | 18 (1.7) |
NDB, National Database of Health Insurance Claims and Specific Health Checkups; JMDC, the JMDC Claims Database; DPC, the Diagnosis Procedure Combination database