Figure 1.
Flow diagram of the studies included in this meta-analysis.
Table 1.
Characteristics and changes in the SBP of patients with hypertension in garlic-treated cases and controls or placebo
| Author name and year (reference) | Population | Number of subjects in garlic-treated group/control or placebo group | Mean BMI kg/m2 (treated/control group) | Medication at baseline | Manufacturer, dose (mg/d)/duration of treatment (weeks) | Mean ± SD SBP pretreated garlic group (mmHg) | Mean ± SD SBP post-treated garlic group (mmHg) | Mean ± SD SBP pretreated placebo group (mmHg) | Mean ± SD SBP post-treated placebo group (mmHg) |
|---|---|---|---|---|---|---|---|---|---|
| Kandziora [32] | Poland | 20/20 | NA | Triamterene/hydrochlorothiazide | Kwai, 600/12 | 178 ± 8 | 162 ± 9 | 178 ± 8 | 173 ± 6 |
| Auer et al. [22] | Germany | 24/23 | NA | NA | Kwai, 600/12 | 171 ± 24.5 | 152 ± 24.5 | 161 ± 14.4 | 152 ± 19.2 |
| Vorberg and Schneider [28] | Germany | 20/20 | NA | NA | Kwai, 900/16 | 144 ± 10.6 | 138 ± 4 | 143.5 ± 10 | 146 ± 6.5 |
| De Santos and ruenwald [29] | Germany | 25/27 | NA | NA | Kwai, 900/24 | 143 ± 21 | 120 ± 13.1 | 144 ± 17 | 145 ± 11.7 |
| Sobenin et al. [26] | Russia | 23/19 | 26.6/27.0 | NA | Allicor, 600/12 | 143.4 ± 7.2 | 136.8 ± 5.8 | 140.3 ± 78 | 139.4 ± 6.5 |
| Sobenin et al. [27] | Russia | 64/20 | 25.4/26.0 | NA | Allicor, 2,400/8 | 154 ± 12.3 | 147 ± 12.8 | 149.8 ± 12.6 | 149.9 ± 11.7 |
| Ried et al. [25] | Australia | 8/12 | 31.0/29.1 | ACE inhibitors, A2 receptor antagonists, β-receptor blockers, Ca-antagonists, and diuretics | Kyolic High Potency, 960/12 | 151.2 ± 7.7 | 136 ± 8 | 152.8 ± 9.3 | 145.4 ± 3.5 |
| Ried et al. [24] | Australia | 39/19 | 29.1/29.9 | ACE inhibitors, A2 receptor ant-agonists, β-receptor blockers, Ca-antagonists, diuretics | Kyolic High Potency, 480/12 | 149.3 ± 13 | 130 ± 12.8 | 148.6 ± 13.1 | 135.9 ± 12.8 |
| Nakasone et al. [23] | Japan | 23/24 | 25.0/23.0 | None | Dentou ninniku ranwo, 188/12 | 141.8 ± 5.6 | 137 ± 7.8 | 141.8 ± 5.6 | 140.4 ± 7.6 |
| Ried et al. [9] | Australia | 50/38 | 27.3/28.3 | ACE inhibitors, A2 receptor antagonists, β-receptor blockers, Ca-antagonists, and diuretics | Kyolic Reserve, 1,200/12 | 148.7 ± 15.3 | 141.7 ± 15.3 | 142 ± 9.4 | 140.3 ± 18.2 |
| Ried et al. [30] | Australia | 23/26 | 28.6/29.7 | ACE inhibitors, A2 receptor antagonists, β-receptor blockers, Ca-antagonists, and diuretics | Kyolic Reserve, 1,200/12 | 153.3 ± 16.4 | 139 ± 15.1 | 144.3 ± 14.2 | 140 ± 16.3 |
| Serrano et al. [31] | Spain | 39/38 | NA | Thiazide, beta blockers, angiotensin II receptor blocker, and calcium channel blockers | Pharmactive Biotech Spain, 300/12 | 146 ± 21 | 143 ± 18 | 144 ± 13 | 138 ± 14 |
Table 2.
Changes in the DBP of patients with hypertension in garlic-treated cases and controls or placebo
| Author name and year | Mean ± SD DBP pretreated garlic group (mmHg) | Mean ± SD DBP post-treated garlic group (mmHg) | Mean ± SD DBP pretreated placebo group (mmHg) | Mean ± SD DBP post-treated placebo group (mmHg) |
|---|---|---|---|---|
| Kandziora [32] | 100 ± 4 | 85 ± 4 | 100 ± 3 | 91 ± 6 |
| Auer et al. [22] | 101 ± 14.7 | 89 ± 4.6 | 97 ± 9.6 | 94 ± 9.6 |
| Vorberg and Schneider [28] | 91 ± 4 | 87 ± 4 | 87.5 ± 6 | 90 ± 4 |
| De Santos and Gruenwald [29] | 89 ± 11 | 80 ± 4.6 | 89 ± 11 | 90 ± 8.3 |
| Sobenin et al. [26] | 88.8 ± 4.3 | 83.8 ± 3.4 | 87.9 ± 4.8 | 85.9 ± 4.4 |
| Sobenin et al. [27] | 95.7 ± 3.8 | 92.9 ± 4.4 | 94.4 ± 6.1 | 93 ± 6.1 |
| Ried et al. [25] | 87.3 ± 7.8 | 91.9 ± 8.3 | 88.6 ± 8 | 84 ± 8.3 |
| Ried et al. [24] | 75.7 ± 12.4 | 68.6 ± 11.6 | 76 ± 12.2 | 70.2 ± 12 |
| Nakasone et al. [23] | 90.9 ± 6.9 | 87 ± 7.1 | 91.6 ± 5.8 | 90.7 ± 6.5 |
| Ried et al. [9] | 89.9 ± 11.7 | 86.1 ± 11.3 | 87.8 ± 9.1 | 86 ± 9 |
| Ried et al. [30] | 93 ± 10.9 | 83.1 ± 10.4 | 90 ± 12.3 | 85.5 ± 13 |
| Serrano et al. [31] | 85 ± 10 | 83 ± 9 | 85 ± 7 | 83 ± 10 |
Figure 2.
Effect of garlic on diminishing SBP in hypertensive patients. Publication bias in the included reports was explored using funnel plots (A). The forest plot revealed a significant decrease in SBP with the treatment of hypertensive patients with garlic compared with those treated with placebo (B). The sensitivity analysis supported the robustness of the meta-analysis (C). All meta-analysis statistics were performed using CMA v4. CI, confidence interval; CMA, Comprehensive Meta-Analysis; SBP, systolic blood pressure.
Figure 3.
Effect of garlic on diminishing DBP in hypertensive patients. Publication bias in the included reports was explored using funnel plots (A). The forest plot revealed a significant decrease in DBP with the treatment of hypertensive patients with garlic compared with those treated with placebo (B). The sensitivity analysis supported the robustness of the meta-analysis (C). All meta-analysis statistics were performed using CMA v4. CI, confidence interval; CMA, Comprehensive Meta-Analysis; DBP, diastolic blood pressure.
Figure 4.
TSA of the reports was performed to investigate the role of garlic extracts in the treatment of hypertension. Reports are considered to investigate the role of garlic in lowering (A) SBP and (B) DBP; however, further studies are not required. In both TSA plots, the z-curve crosses the alpha spending boundary and reaches the required information size line. DBP, diastolic blood pressure; SBP, systolic blood pressure; TSA, trial sequential analysis.