Table 4 Risk of bias and summary of risk of selected studies
Risk of bias | Krishnaveni et al. 2011 [37] | Veena et al. 2017 [38] | Nandal et al. 2016 [39] | Dasgupta et al. 2012 [42] | Sachan et al. 2005 [31] | Sahu et al. 2009 [33] | Farrant et al. 2009 [32] | Sharma et al. 2016Â [36] | Marwaha et al. 2011 [7] | Jani et al. 2014 [9] | Ajmani et al. 2016 [35] | Chary et al. 2015 [41] | Kumar et al. 2015 [40] | Singla et al. 2015 [34] | Sablok et al. 2015 [43] |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Representation of data | High risk | High risk | High risk | High risk | High risk | Low risk | High risk | High risk | High risk | High risk | High risk | High risk | High risk | High risk | High risk |
Sampling | High risk | High risk | High risk | High risk | High risk | low risk | High risk | high risk | High risk | High risk | High risk | High risk | High risk | High risk | High risk |
Random selection | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
Non-response bias | High risk | High risk | Low risk | Low risk | High risk | Low risk | High risk | High risk | Low risk | Low risk | Low risk | Low risk | High risk | High risk | Low risk |
Data collected directly from subject | Low risk | Low risk | Low risk | High risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
Case definition | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
Reliability and validity of method | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
Same mode of data collected | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
Length of the shortest period of the prevalence | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk | Low risk |
Numerator and denominator | High risk | High risk | High risk | High risk | High risk | Low risk | High risk | High risk | High risk | High risk | High risk | High risk | High risk | High risk | Low risk |
Summary* | High risk of bias | High risk of bias | High risk of bias | High risk of bias | High risk of bias | Low risk of bias | High risk of bias | High risk of bias | High risk of bias | High risk of bias | High risk of bias | High risk of bias | High risk of bias | High risk of bias | Moderate risk of bias |