Table 1 Subgroup analysis
Classification criteria | Subgroups | No. of Studies | P value | OR (95% CI) | I-squared (%) | P value for within-group heterogeneity | P value for between-group heterogeneity |
|---|---|---|---|---|---|---|---|
Major bleeding | Â | Â | Â | Â | Â | Â | Â |
 Year of study | Before2010 | 8 | <0.001 | 4.63(2.48,8.64) | 38.9 | 0.120 | 0.136 |
| Â | After 2010 | 9 | 0.002 | 2.47(1.39,4.38) | 80.9 | <0.001 | |
 Type of disease | Atrial fibrillation(AF) | 6 | <0.001 | 2.66(1.73,4.08) | 47.9 | 0.087 | 0.244 |
| Â | Others | 11 | <0.001 | 4.50(2.12,9.51) | 75.4 | <0.001 | |
 Study area | America | 11 | <0.001 | 3.10(1.80,5.36) | 79.9 | <0.001 | 0.777 |
| Â | Europe | 5 | 0.014 | 3.69(1.30,10.48) | 56.1 | 0.059 | |
| Â | Korea | 1 | 0.007 | 3.34(1.38,8.08) | NA | NA | |
 Type of anticoagulant | Warfarin | 11 | <0.001 | 3.59(2.37,5.44) | 16.9 | 0.283 | 0.213 |
| Â | new oral anticoagulant(NOAC) | 1 | 0.013 | 5.63(1.44,21.94) | NA | NA | |
| Â | Mixed | 5 | 0.059 | 2.22(0.97,5.09) | 89.9 | <0.001 | |
 Design of the control | Interrupt OAC Interrupted | 10 | <0.001 | 2.52(1.54,4.13) | 76.8 | <0.001 | 0.068 |
| Â | Continue OAC Continued | 4 | 0.085 | 4.33(0.82,22.92) | 75.3 | 0.007 | |
| Â | Non-OAC | 1 | 0.007 | 7.84(1.74,35.35) | NA | NA | |
| Â | Mixed | 2 | <0.001 | 7.27(2.71,19.49) | 0.0 | 0.592 | |
 Patients’ number of subjects | Less than 2000 | 13 | <0.001 | 3.64(2.22,5.96) | 40.7 | 0.063 | 0.371 |
| Â | More than 2000 | 4 | 0.028 | 2.51(1.11,5.68) | 91.4 | <0.001 | |
 Study design | Randomized controlled trial(RCT) | 5 | 0.040 | 2.42(1.04,5.65) | 87.6 | <0.001 | 0.298 |
| Â | Non-RCT | 12 | <0.001 | 3.65(2.29,5.82) | 43.3 | 0.055 | |
 Type of heparin | Unfractionated heparin(UFH) | 1 | 0.007 | 3.34(1.38,8.08) | NA | NA | 0.856 |
| Â | Low molecular weight heparin(LMWH) | 5 | <0.001 | 2.68(1.61,4.46) | 0.0 | 0.655 | |
| Â | Both of LMWH and UFH | 11 | <0.001 | 3.50(1.89,6.49) | 82.6 | <0.001 | |
Thromboemlism | Â | Â | Â | Â | Â | Â | Â |
 Year of study | Before2010 | 9 | 0.038 | 0.55(0.31,0.97) | 2.7 | 0.412 | 0.198 |
| Â | After 2010 | 8 | 0.513 | 1.41(0.50,3.99) | 76.1 | <0.001 | |
 Type of disease | Atrial fibrillation(AF) | 7 | 0.817 | 1.17(0.30,4.53) | 86.8 | <0.001 | 0.606 |
| Â | Others | 10 | 0.659 | 0.89(0.52,1.52) | 0.0 | 0.876 | |
 Study area | America | 13 | 0.794 | 1.11(0.51,2.44) | 79.9 | <0.001 | 0.781 |
| Â | Europe | 3 | 0.090 | 0.32(0.09,1.19) | 56.1 | 0.059 | |
| Â | Korea | 1 | 0.322 | 4.06(0.25,64.99) | NA | NA | |
 Type of anticoagulant | Warfarin | 12 | 0.194 | 0.71(0.42,1.19) | 5.1 | 0.395 | 0.550 |
| Â | Mixed | 5 | 0.893 | 1.11(0.25,4.94) | 86.5 | <0.001 | |
 Design of the control | Interrupt OAC | 11 | 0.656 | 1.21(0.52,2.82) | 76.5 | <0.001 | 0.355 |
| Â | Continue OAC | 3 | 0.198 | 0.42(0.11,1.58) | 12.0 | 0.321 | |
| Â | Non-OAC | 2 | 0.963 | 0.93(0.04,22.99) | 55.8 | 0.132 | |
| Â | Mixed | 1 | 0.449 | 0.33(0.02,5.93) | NA | NA | |
 Patients’ number of subjects | Less than 2000 | 12 | 0.317 | 0.75(0.44,1.31) | 0.0 | 0.693 | 0.260 |
| Â | More than 2000 | 5 | 0.519 | 1.64(0.36,7.43) | 89.9 | <0.001 | |
 Study design | Randomized controlled trial(RCT) | 5 | 0.371 | 1.83(0.49,2.00) | 79.2 | 0.001 | 0.298 |
| Â | Non-RCT | 12 | 0.181 | 0.66(0.36,1.21) | 26.5 | 0.184 | |
 Type of heparin | Unfractionated heparin(UFH) | 1 | 0.322 | 4.06(0.25,64.99) | NA | NA | 0.856 |
| Â | Low molecular weight heparin(LMWH) | 5 | 0.159 | 0.60(0.29,1.22) | 28.5 | 0.232 | |
| Â | Both of LMWH and UFH | 11 | 0.807 | 1.13(0.43,2.94) | 70.6 | <0.001 |