Table 3 Subgroup analyses of GLS between DMD and control groups
| Â | Number of studies | Test of difference | Test of Heterogeneity | ||
|---|---|---|---|---|---|
WMD (95% CI) | P value | I2 (%) | P value | ||
Country | |||||
 USA/Europe/Egypt | 4 | 5.01 (3.73–6.29) | < 0.001 | 40.5 | 0.169 |
 China/Korea | 4 | 3.28 (1.63–4.93) | < 0.001 | 62.4 | 0.047 |
Quality of study | |||||
 Medium quality | 5 | 4.89 (3.78–6.00) | < 0.001 | 28.3 | 0.233 |
 High quality | 3 | 3.04 (1.04–5.05) | 0.003 | 71.5 | 0.030 |
Method | |||||
 Two-dimensional STE | 4 | 4.90 (3.62–6.19) | < 0.001 | 40.1 | 0.171 |
 Three-dimensional STE | 4 | 3.41 (1.64–5.17) | < 0.001 | 67.8 | 0.025 |
Machine/software | |||||
 GE Vivid E9 with EchoPAC | 7 | 4.07 (2.83–5.31) | < 0.001 | 66.1 | 0.007 |
 Philips iE33 with Qlab | 1 | 5.20 (2.51–7.89) | < 0.001 | – | – |