Table 4.
Subgroup analyses by study design and type of control
| Subgroups | SBP | DBP | |||||
|---|---|---|---|---|---|---|---|
| Mean difference in mmHg (95% CI) | P | I2 | Mean difference in mmHg (95% CI) | P | I2 | ||
| Study design | Crossover [10,12,13,18,20,21,23] | -4.91 (-7.94, -1.88) | 0.002 | 80% | -3.24 (-5.36, -1.12) | 0.003 | 67% |
| Parallel [11,15-17,21-23] | -2.01 (-3.42, -0.60) | 0.005 | 9% | -1.20 (-2.29, -0.11) | 0.03 | 12% | |
| Parallela [11,15,17,21-23] | -0.43 (-2.80, 1.94) | 0.72 | 0% | -0.25 (-1.83, 1.33) | 0.75 | 0% | |
| Type of control | Flavanol-free: white chocolate, milk, pills [11,15,17,20,21] | -4.21 (-6.65, -1.77) | 0.0007 | 82% | -2.81 (-4.52, -1.10) | 0.001 | 70% |
| Low-flavanol: drink, bar, tablet [10,13,16,18,22-24] | 0.74 (-2.92, 4.40) | 0.69 | 53% | -0.38 (-2.00, 1.24) | 0.65 | 0% | |
SBP, systolic blood pressure; DBP, diastolic blood pressure; mmHg, millimetre mercury; CI, confidence interval; P, probability value (P < 0.05 statistically significant); I2, heterogeneity test.
aSensitivity analysis excluding trial [16], as this trial used a notably lower dose and longer duration than the other trials included in the meta-analysis.