Table 3.
Risk of bias according to CSI score of studies included in the systematic review (CSI – Confounding-Selection-Information bias score; (q)PCR – (quantitative real-time)polymerase chain reaction; QC – quality control)
| Author, year | CSI score | Explanation |
||
|---|---|---|---|---|
| C (confounding bias) | S (selection bias) | I (information bias) | ||
| Jablonska et al, 2014 (18) |
ACB |
A-no apparent confounding |
C-no information about controls recruitment |
I1:A-cases confirmed by antibody assay and PCR
I2:B-antibody negative controls
I3:A-genotyping QC reported |
| Taniguchi et al, 2013 (19) |
CBC |
C-no information whether controls were matched to cases |
B-controls drawn from database (to represent general population) |
I1:B-majority of cases confirmed by clinical status and urine-filter based screening, only few confirmed by PCR
I2:C-no description of disease status in controls
I3:A-genotyping QC reported |
| Wujcicka et al, 2015 (20) |
ABC |
A-no apparent confounding |
B-hospital based |
I1:A-cases confirmed by serological tests and qPCR
I2:C-not reported clearly how controls were confirmed as uninfected
I3:A-genotyping QC reported |
| Hu et al, 2010 (21) |
ACC |
A-no apparent confounding |
C-no information about controls recruitment |
I1:A-cases confirmed by qPCR and antibody assay
I2:B-antibody negative controls
I3:C-no genotyping QC reported |
| Szala et al, 2011 (22) | ABC | A-no apparent confounding | B-hospital based | I1:B-cases confirmed by qPCR and/or antibody assay I2:C-not reported clearly how controls were confirmed as uninfected I3:C-no genotyping QC reported |