Table 2.
Evaluation of the quality using Newcastle-Ottawa scale.
| Authors | HBV infection cases(n) | HCV infection cases(n) | CCA cases(n) | ICC cases(n) | ECC cases(n) | Exposure Ascertainment | Comparability of Simultaneous Group and Reference | Possible Factors Assessment in Selection Bias | |
|---|---|---|---|---|---|---|---|---|---|
| Lian-Yuan Tao et al. (2016) | 151 | 9 | 312 | 312 | NA | Hospital records | No restriction or matching | Record linkage | Unmentioned |
| Yan-Ming Zhou et al. (2015) | 88 | 1 | 126 | NA | NA | Hospital tests | 4:1 matched healthy controls for age and sex | Record linkage | Hospital-based study |
| Ban Seok Lee et al. (2015) | 28 | 11 | 276 | 83 | 193 | Hospital tests | 2:1 matched controls for age, sex, and date of diagnosis | Record linkage | Hospital-based study and diagnosis bias |
| Kazuya Matsumoto et al. (2014) | 7 | NA | 103 | 50 | 53 | Hospital tests and reviews | No restriction or matching | Record linkage | Possible bias in allocation to simultaneous group |
| Yu Zhou et al. (2013) | 27 | NA | 222 | NA | 222 | Pathological diagnosis | Controls matched for sex and age | Record linkage | Hospital-based study |
| Jeffrey S. Chang et al. (2013) | 376 | 250 | 5157 | 2978 | 2179 | The datasets of the NHIRD | 4:1 matched cancer-free controls for sex, age (birthday), and the time of case diagnosis (reference date for the controls) | Record linkage | Selection and recall biases |
| Qiao Wu et al. (2012) | 34 | NA | 188 | 102 | 86 | PUMCH Patient Information Database | 3:1 matched controls for gender and age | Record linkage | Differential referral patterns |
| Zhenliang QU et al. (2012) | 19 | 46 | 212 | NA | 212 | Hospital tests | Participants with benign biliary disease with cholelithiasis or acute cholangitis undergoing surgical intervention | Record linkage | Hospital-based study |
| Ning-fu Peng et al. (2011) | 31 | NA | 98 | 98 | NA | Medical records | 3:1 matched cancer-free controls for sex, age (birthday) | Record linkage | Mechanism confusion |
| Wen-Ke Cai et al. (2011) | 23 | NA | 313 | NA | NA | Hospital records | 2:1 matched controls for age and sex | Record linkage | Geographic regions limitation |
| Petcharin Srivatanakul et al. (2010) | 11 | NA | 106 | NA | NA | Hospital records | 1:1 matched controls for sex, age (± years) and by residence | Record linkage | Unmentioned |
| Rui-qing Liu et al. (2013) | 37(total number for study of CA19-9) | NA | NA | NA | NA | Hospital records | Non-HBV group | Record linkage | Small population |
| Chul-Soo Ahn et al. (2016) | 37(total number for study of lymphnode involvement) | NA | 292 | 292 | NA | Hospital records | Non-HBV group | Record linkage | Single-center study and limited sample size |
| Summation | 869 | 317 | 7405 | 3915 | 2945 | ||||
NA: not available; CCA: cholangiocarcinoma; ICC: intrahepatic cholangiocarcinoma; ECC: extrahepatic cholangiocarcinoma