Table 1.

Risk of bias assessment tool [19]].

A. Selection (Does the patient(s) represent(s) the whole experience of the investigator (center) or is the selection method unclear to the extent that other patients with similar presentation may not have been reported?)

i. Cases were selected over a specified range of period? 2 points

ii. Selection approach unclear? 1 point

B. Ascertainment of outcome: (How were the cases ascertained?)

i. Clinical records? 2 points

ii. Self-report or other methods? 1point

C. Reporting:

i. Cases described in sufficient details? 2 points

ii. Cases scanty with some missing information? 1point