Table 2. Results of subgroup analysis.

Outcome or Subgroup	Studies	Participants	Statistical Method	Effect Estimate
2.1 Study type	3		Risk Ratio (M-H, Random, 95% CI)
2.1.1 RCT	2	326	Risk Ratio (M-H, Random, 95% CI)	1.00 [0.98, 1.02]
2.1.2 quasi-RCT	1	26	Risk Ratio (M-H, Random, 95% CI)	1.50 [0.95, 2.37]
2.2 Follow-up duration	3		Risk Ratio (M-H, Random, 95% CI)
2.2.1 1 year	2	74	Risk Ratio (M-H, Random, 95% CI)	1.16 [0.68, 1.98]
2.2.2 2 years	1	278	Risk Ratio (M-H, Random, 95% CI)	1.00 [0.99, 1.01]

RCTs: randomized controlled trials.