4. Enhanced patient referral versus simple patient referral, re‐infection in the index patient, effect size.

Comparison	N (studies)	n (participants)	Study ID	RR (95% CI)	Test for heterogeneity I2; Chi2, P value
Home sampling kit vs. simple patient referral	1	220	Cameron 2009	2.14 (0.91 to 5.05)	n/a
Information booklet vs. simple patient referral	2	942	Kissinger 2005; Kissinger 2006	0.55 (0.22 to 1.33)	76%; 4.19, P value = 0.04
Patient referral (DIS/health adviser) vs. patient referral (nurse)	1	140	Low 2005	0.35 (0.01 to 8.51)	n/a
Disease‐specific website vs. simple patient referral	1	105	Tomnay 2006	3.12 (0.17 to 58.73)	n/a
Additional counselling vs. simple patient referral	1	600	Wilson 2009	0.49 (0.27 to 0.89)	n/a

Enhanced patient referral is taken as the experimental group. Risk ratio (RR) < 1 indicates a lower re‐infection risk after enhanced patient referral than simple patient referral. If RR = 1, the risk of re‐infection is the same in both groups. If RR > 1, there is a higher risk of re‐infection in the enhanced patient referral group. In the trial by Low et al., the outcome was assessed in a minority of index patients.

CI: confidence interval; DIS: disease intervention specialist; n/a: not applicable; RR: risk ratio.