Newcastle Ottawa criteria

(Yes, No, Uncertain)

El Ansari et al. [4]

Lee et al. [5]

Jahan et al. [7]

Nur et al. [8]

Balmus et al. [9]

Chu et al. [10]

Gomathi et al. [11]

Awadalla et al. [12]

Chu et al. [13]

Rahman et al. [14]

Representative of the exposed cohort

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Selection of external control

No

No

No

No

Yes

No

No

No

No

No

Ascertainment of exposure

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

The desired outcome is not present at the start of the investigation.

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Comparability of the main factor

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Comparability of the additional factor

Yes

Yes

Yes

No

No

No

No

Yes

Yes

Yes

Assessment of outcome

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Enough time for follow-up

No

No

No

No

No

No

No

No

No

No

Adequacy of follow up

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Evaluation

7/9

7/9

7/9

6/9

7/9

6/9

6/9

6/9

7/9

6/9