Quality items

No. of studies

Randomization sequence generation

-Adequate

15

-Inadequate (quasi-RCT)

5

-Unclear

2

-Cluster design

1

Allocation concealment

-Unclear

23

Sample representativeness

-Very likely

13

-Somewhat likely

6

-Unlikely or cannot tell

4

Sample size calculated

-Yes

15

-Unclear or no

8

Comparability between groups

-No significant differences

13

-Some difference or could not tell

10

Loss to follow up

-Reported

18

-No reported

5

Outcomes reported

-Blood pressure

13

-Adequate hypertension control

11