Comparison 2. Heroin Provision (various modality and route of administration) vs any other treatment.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Retention in treatment	6	1535	Risk Ratio (IV, Random, 95% CI)	1.44 [1.16, 1.79]
2 Mortality	5	1573	Risk Ratio (IV, Random, 95% CI)	0.78 [0.32, 1.89]