Table 1 Categorization of the quality of the comparator dataset

1

Autopsy diagnosis

1 (1.5%)

[53]

2

Hospital diagnosis with evidence suggestive that investigation findings (i.e. except autopsy) were used in the diagnosis in addition to the signs and symptoms

36 (54.5%)

[8, 9, 15, 21,22,23,24,25,26,27,28,29, 31,32,33,34, 37,38,39,40, 44, 47,48,49,50, 52, 54, 55, 58, 59, 63,64,65, 70, 72, 76]

3

Hospital diagnosis without further details of the criteria used/Hospital diagnosis only based on signs and symptoms

7 (10.6%)

[16, 17, 30, 36, 51, 56, 67]

4

Externally made diagnosis (e.g. by a physician not involved in the management of the patient) using available clinical records

11 (16.7%)

[35, 41, 45, 46, 60,61,62, 68, 69, 74, 77]

5

Civil registry or other non-medical records

8 (12.1%)

[14, 18,19,20, 42, 57, 66, 73]

Mixed

More than 1 level

3 (4.5%)

[43, 71, 75]

Total

66 (100.0%)