Table 4.
Subgroup analysis performed according to study-level characteristics considered as potential sources of heterogeneity for the outcome LVEF
| Subdivision | N | SMD (95% CI) | SMD =0 Z |
P-value | I2a % |
|---|---|---|---|---|---|
| All studies | 18 | 0.47 (0.20, 0.74) | 3.46 | 0.001 | 80.8 |
| Concealment of randomization | |||||
| Yes | 13 | 0.46 (0.11, 0.81) | 2.59 | 0.010 | 85.1 |
| Inadequate/unclear | 5 | 0.49 (0.19, 0.80) | 3.18 | 0.001 | 36,1 |
| Outcome assessor blinded to treatment group | |||||
| Yes | 15 | 0.44 (0.13, 0.74) | 2.83 | 0.005 | 83.0 |
| Inadequate/unclear | 3 | 0.47 (0.20, 0.74) | 4.07 | 0.0001 | 00.0 |
| Intention-to-treat strategy | |||||
| Yes | 14 | 0.46 (0.14, 0.79) | 2.79 | 0.005 | 84.0 |
| No/unclear | 4 | 0.50 (0.10, 0.90) | 2.47 | 0.014 | 51.2 |
| A priori power estimation | |||||
| Yes | 7 | 0.15 (−0.06, 0.36) | 1.38 | 0.168 | 37.5 |
| No/unclear | 11 | 0.67 (0.24, 1.10) | 3.08 | 0.002 | 84.8 |
| Dropouts | |||||
| Yes | 8 | 0.03 (−0.57, 0.51) | 0.11 | 0.910 | 92.5 |
| No/unclear | 10 | −1.06 (−1.38, −0.73) | 6.31 | 0.0001 | 59.5 |
| Nonbiased and powered studies | |||||
| Yes | 8 | 0.17 (−0.02, 0.36) | 1.74 | 0.082 | 32.0 |
| No | 10 | 0.71 (0.23, 1.19) | 2.91 | 0.004 | 86.1 |
Note:
a
I2= the variation in SMD due to heterogeneity.
Abbreviations: LVEF, left ventricular ejection fraction; SMD, standardized mean difference; CI, confidence interval.