Table 1.
Subgroup analysis according to region, study design and NOS score
| Heterogeneity | ||||
|---|---|---|---|---|
| Confounding factors | NO. studies | Odds ratio (95 % CI) | I 2 | p |
| Region | ||||
| Eastern | ||||
| BDST | 4 | 12.34 (4.54–33.57) | 59.1 % | 0.062 |
| GBST | 4 | 1.77 (0.88–3.58) | 85.7 % | 0.000 |
| Western | ||||
| BDST | 2 | 23.35 (17.63–30.92) | 0.0 % | 0.974 |
| GBST | 2 | 2.81 (1.03–7.72) | 36.3 % | 0.210 |
| Study design | ||||
| Nationwide | ||||
| BDST | 3 | 21.07 (16.85–26.36) | 0.0 % | 0.494 |
| GBST | 2 | 2.78 (2.37–3.26) | 0.0 % | 0.328 |
| Hospital-based | ||||
| BDST | 3 | 9.75 (1.73–54.84) | 62.5 % | 0.056 |
| GBST | 4 | 1.42 (0.63–3.19) | 70 % | 0.019 |
| NOS score | ||||
| High | ||||
| BDST | 3 | 18.49 (12.90–26.50) | 0.0 % | 0.463 |
| GBST | 3 | 2.58 (1.59–4.21) | 53.2 % | 0.118 |
| Moderate | ||||
| BDST | 3 | 9.53 (2.55–35.59) | 75.2 % | 0.018 |
| GBST | 3 | 1.57 (0.54–4.61) | 79.4 % | 0.008 |
CI confidence interval, EHST extrahepatic bile duct stone or choledocholithiasis, GBST gallbladder stone or cholecystolithiasis