Table 4.
Risk of bias for included studies.
|
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | Scores | Summary risk of bias |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Hospital–wide studies | ||||||||||||
| Xiu et al. (17) | N | N | N | N | Y | N | Y | Y | Y | Y | 5 | High |
| Zhou et al. (20) | N | N | N | Y | Y | Y | Y | Y | Y | Y | 7 | Moderate |
| Jiang et al. (21) | N | N | N | Y | Y | N | Y | Y | Y | Y | 6 | Moderate |
| Tian et al. (25) | N | N | N | Y | N | Y | Y | Y | Y | Y | 6 | Moderate |
| ICU–based studies | ||||||||||||
| Cheng et al. (18) | Y | N | N | Y | Y | Y | Y | Y | Y | Y | 8 | Moderate |
| Zhou et al. (19) | Y | N | N | Y | Y | Y | Y | Y | N | Y | 7 | Moderate |
| Wang et al. (22) | Y | N | N | Y | Y | Y | Y | Y | Y | Y | 8 | Moderate |
| Xie et al. (23) | Y | N | Y | Y | Y | Y | Y | Y | Y | Y | 9 | Low |
| Cao et al. (24) | N | N | N | Y | Y | Y | Y | Y | Y | Y | 7 | Moderate |
Was the study's target population a close representation of the national population in relation to relevant variables?
Was the sampling frame a true or close representation of the target population?
Was some form of random selection used to select the sample, or was a census undertaken?
Was the likelihood of non-response bias minimal?
Were data collected directly from the subjects (as opposed to a proxy)?
Was an acceptable case definition used in the study?
Was the study instrument that measured the parameter of interest shown to have validity and reliability?
Was the same mode of data collection used for all subjects?
Was the length of the shortest prevalence period for the parameter of interest appropriate?
Were the numerator(s) and denominator(s) for the parameter of interest appropriate?
The summary risk of bias of studies was graded as “high risk” if the risk of bias of two or more items was judged as “high.” The summary risk of bias was graded as “moderate risk” if the risk of bias of one item was judged as “high” and a maximum of one other item was judged as “moderate.” In addition, the overall risk of bias was graded as “moderate” if two or a maximum of three items were judged as “moderate” risk of bias. The summary risk of bias of studies was judged as “low” if the risk of bias of a maximum of one item was judged as “moderate”.