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	Serious1	Serious2	not serious	Serious3	undetected	VERY LOW due to risk of bias, inconsistency, imprecision	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	serious1	serious2	no serious indirectness	no serious imprecision	undetected	LOW1,2 due to risk of bias, inconsistency	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	Serious2	no serious indirectness	no serious imprecision	undetected	MODERATE due to inconsistency	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	HIGH	272	270	—	The mean diastolic blood pressure in the intervention group was 2.437 lower (3.487 to 1.387 lower)

¹Most of the information concerning randomization and blinding was unclear in the analyses of the individual trials.

²High heterogeneity.

³Few patients analysed.