Table 2.
Methodologic assessment of study design quality using an adaptation of the quality index [16]. Numbering refers to the quality index item
| ITEM | STUDY | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Almarwani et al. (2016a) [39] | Almarwani et al. (2016b) [40] | Decker et al. (2016) [41] | Ihlen et al. (2012) [42] | Kang et al. (2008) [43] | Lovden et al. (2008) [38] | Marigold et al. (2008) [44] | Owings et al. (2004a) [45] | Paterson et al. (2009) [46] | Thies et al. (2005) [47] | Woledge et al. (2005) [48] | |
| 1. Is the hypothesis/aim/objective of the study clearly described? | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| 2. Are the main outcomes to be measured clearly described in the Introduction or Methods section? | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| 3. Are the characteristics of the participants included in the study clearly described? | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 1 |
| 5. Are the distributions of the principal confounders in each group of subjects to be compared clearly described? | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 |
| 6. Are the main findings of the study clearly described? | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| 7. Does the study provide estimates of the random variability in the data for the main outcomes? | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| 10. Have actual probability values been reported (e.g. 0.035 rather than < 0.05) for the main outcomes except where the probability value is less than 0.001? | 1 | 1 | 1 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 1 |
| 11. Were the subjects asked to participate in the study representative of the entire population from which they were recruited? | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 1 |
| 12. Were those subjects who were prepared to participate representative of the entire population from which they were recruited? | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 13. Were the staff, place and facilities where the study was set representative of a laboratory environment? | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| 16. If any of the results of the study were based on “data dredging”, was this made clear? | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| 20. Were the main outcome measures used accurate (valid and reliable)? | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| 21. Were the subjects recruited from the same population? | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 0 | 0 | 1 | 0 |
| 22. Were study subjects recruited over a defined period of time? | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 25. Was there adequate adjustment for confounding in the analysis from which the main findings were drawn? | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| 27. Did the study have a power analysis? | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| TOTAL | 14 | 14 | 12 | 10 | 13 | 13 | 14 | 11 | 11 | 14 | 13 |