Fifteen studies (1,7091 participants) were included. The overall quality of included evidence was rated as low.
Pooled rates of enrolment grouped (according to strategy) were: other (patient letters) 73% (95% CI 39% to 92%; Ι²=90.95, two studies), combined systematic and liaison strategies 66% (95% CI 54% to 77%; Ι²=98.1, four studies), systematic strategies alone 45% (95% 33% to 57%; Ι²=97.78, six trials), liaison strategies alone 44% (95% CI 35% to 53%, Ι²=93.28, six studies) and usual 24% (95% CI 18% to 31%; five studies).