Table 1 Number of enrolled patients

All patients (n = 229)

- Hokkaido University Hospital

91 (39.7)

- Keio University Hospital

31 (13.5)

- Sapporo Medical University Hospital

26 (11.4)

- Tohoku University Hospital

26 (11.4)

- Obihiro-Kosei Hospital

17 (7.4)

- Asahikawa Medical University Hospital

11 (4.8)

- Tomakomai City Hospital

9 (3.9)

- Nippon Medical School Hospital

5 (2.2)

- Tokyo Women’s Medical University Hospital

5 (2.2)

- Japanese Red Cross Kitami Hospital

4 (1.7)

- Sapporo City General Hospital

2 (0.9)

- Tohoku Medical and Pharmaceutical University Hospital

2 (0.9)

All patients (n = 229)

- Prospective

7 (31.0)

- Prospective + retrospective

34 (14.8)

- Retrospective

188 (82.1)