Table 5.

Incorporation of risk of bias in the interpretation of review findings

Did the review consider the overall risk of bias across the body of evidence in the interpretation of findings?
Yes, overall high risk of bias is described as a limitation	11 (7.3%)
Yes, overall low risk of bias is used to support findings	14 (9.3%)
No	125 (83.3%)
Did the review consider bias due to the selection of participants in the interpretation of findings?
Yes, potential for selection bias is acknowledged as a limitation	14 (9.3%)
Yes, selection bias is described as unlikely	10 (6.7%)
No	126 (84.0%)
Did the review consider bias due to confounding in the interpretation of findings?
Yes, potential for confounding is acknowledged as a limitation	77 (51.3%)
Yes, confounding is described as unlikely	2 (1.3%)
No	71 (47.3%)
Did the review consider bias due to the misclassification of the exposure in the interpretation of findings?
Yes, potential for bias due to misclassification of the exposure is acknowledged as a limitation	85 (56.7%)
Yes, bias due to misclassification of the exposure is described as unlikely	6 (4.0%)
No	59 (39.3%)
Did the review consider bias due to departures from the intended exposure in the interpretation of findings?
Yes, potential for bias due to departures from the intended exposure is acknowledged as a limitation	23 (15.3%)
Yes, bias due to departures from the intended exposure is described as unlikely	0 (0%)
No	127 (84.7%)
Did the review consider bias due to missing outcome data in the interpretation of findings?
Yes, potential for bias due to missing outcome data is acknowledged as a limitation	2 (1.3%)
Yes, bias due to missing outcome data is described as unlikely	0 (0.0%)
No	148 (98.6%)
Did the review consider bias in the measurement of the outcome in the interpretation of findings?
Yes, potential for bias in the measurement of the outcome is acknowledged as a limitation	23 (15.3%)
Yes, bias in the measurement of the outcome is described as unlikely	4 (2.7%)
No	123 (82.0%)
Did the review consider bias due to selective reporting in the interpretation of findings?
Yes, potential for selective reporting bias is acknowledged as a limitation	1 (0.6%)
Yes, selective reporting bias is described as unlikely	0 (0.0%)
No	149 (99.3%)
Did the review hypothesise about the likely direction of bias?
Yes, the authors hypothesise that effects for studies at high risk of bias are likely to have been biased away from the null	6 (4.0%)
Yes, the authors hypothesise that effects for studies at high risk of bias are likely to have been biased towards the null	14 (9.3%)
No	130 (86.7%)
Did the review evaluate the certainty of evidence using a formal system?
Yes, using GRADE15	9 (6%)
Yes, using NutriGRADE79	2 (1.3%)
Yes, using SIGN80	1 (0.7%)
Yes, using the NHMRC FORM methodology81	1 (0.7%)
Yes, using a modified version American Diabetes Association system32	1 (0.7%)
Yes, using a modified version of the National Osteoporosis Foundation evidence grading system82	1 (0.7%)
Yes, using an ad hoc system	1 (0.7%)
No	134 (89.3%)
Among reviews that used a formal system to evaluate the certainty of evidence (n=16; 10.7%), was the certainty of evidence downgraded due to risk of bias?
Yes	5 (31.3%)
No	11 (73.3%)