Table 3 GRADE evidence profiles for the meta-analysis of the effects of vitamin C and vitamin D on blood pressure in patients with type 2 diabetes.
Vitamin C | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Quality assessment | Summary of Findings | |||||||||
Participants (studies) Follow-up | Risk of bias | Inconsistency | Indirectness | Imprecision | Publication bias | Overall quality of evidence | Study event rates (%) | Relative effect (95% CI) | Anticipated absolute effects | |
Intervention | Control | |||||||||
Systolic Blood Pressure (IMPORTANT OUTCOME; Better indicated by lower values) | ||||||||||
65 (2 studies) 3.5 weeks | Serious 1 | Serious 2 | not serious | Serious 3 | undetected |
| 32 | 33 | — | The mean systolic blood pressure in the intervention group was 3.93 lower (14.78 lower to 6.92 higher) |
Diastolic Blood Pressure (IMPORTANT OUTCOME; Better indicated by lower values) | ||||||||||
65 (2 studies) 6.35 weeks | serious 1 | serious 2 | no serious indirectness | no serious imprecision | undetected |
| 32 | 33 | — | The mean diastolic blood pressure in the intervention group was 2.88 lower (2.88 to 0.46 lower) |
Vitamin D | ||||||||||
Systolic Blood Pressure (Better indicated by lower values) | ||||||||||
542 (7 studies) 3–52 weeks | no serious risk of bias | Serious 2 | no serious indirectness | no serious imprecision | undetected |
| 272 | 270 | — | The mean systolic blood pressure in the intervention group was 4.558 lower (7.65 to 1.465 lower) |
Diastolic Blood Pressure (IMPORTANT OUTCOME; Better indicated by lower values) | ||||||||||
542 (7 studies) 3–52 weeks | no serious risk of bias | no serious inconsistency | no serious indirectness | no serious imprecision | undetected |
| 272 | 270 | — | The mean diastolic blood pressure in the intervention group was 2.437 lower (3.487 to 1.387 lower) |
VERY LOW due to risk of bias, inconsistency, imprecision
LOW1 , 2 due to risk of bias, inconsistency
MODERATE due to inconsistency
HIGH