Table 2.
Proportion of studies meeting individual study quality criteria
| Animal studies (n=179) | Human studies (n=21) | |
|---|---|---|
| Hypothesis, aim, and objective definition | ||
| Clear | 167 (93%) | 18 (86%) |
| Unclear | 10 (6%) | 3 (14%) |
| Unknown | 2 (1%) | 0 |
| Description of animal and human participants | ||
| Good | 57 (32%) | 9 (43%) |
| Poor | 118 (66%) | 10 (48%) |
| Unknown | 4 (2%) | 2 (10%) |
| Intervention descriptions | ||
| Good | 112 (63%) | 14 (67%) |
| Poor | 64 (35%) | 6 (29%) |
| Unknown | 3 (2%) | 1 (5%) |
| Description of main outcomes | ||
| Good quality | 157 (88%) | 16 (76%) |
| Poor quality | 18 (10%) | 3 (14%) |
| Unknown | 4 (2%) | 2 (10%) |
| Provision of estimates of variability | ||
| Yes | 44 (25%) | 7 (33%) |
| No | 133 (74%) | 13 (62%) |
| Unknown | 2 (1%) | 1 (5%) |
| Representative study population | ||
| Yes | 37 (21%) | 3 (14%) |
| No | 82 (47%) | 7 (33%) |
| Unknown | 58 (32%) | 11 (52%) |
| Recruitment of intervention and control group populations | ||
| Same source | 78 (44%) | 7 (33%) |
| Alternate sources | 46 (26%) | 7 (33%) |
| Unknown | 53 (30%) | 7 (33%) |
| Recruitment window of intervention and control group populations | ||
| Same time period | 137 (77%) | 7 (44%) |
| Different time periods | 10 (5%) | 4 (25%) |
| Unknown | 32 (18%) | 5 (31%) |
| Adjustment for confounders | ||
| Adequate adjustment | 27 (14%) | 4 (19%) |
| Inadequate adjustment | 69 (70%) | 11 (52%) |
| Unknown | 28 (16%) | 6 (29%) |