Low 2006b.

Methods	Setting: 27 general practices in Bristol and Birmingham, UK Enrolment: participants enrolled from March 2001 to October 2002 Follow‐up: 6 weeks after randomisation there was telephone follow‐up of index patient
Participants	140 index patients (92 woman and 48 men) with Chlamydia trachomatis were randomised Inclusion criteria Positive chlamydia test result received at their general practise Exclusion criteria No criteria specified
Interventions	All participants received antibiotic treatment before randomisation Simple patient referral with counselling from practice nurse (n = 72) Nurses received 1 day of training about sexual history taking, management of chlamydia and PN. The index patient had a PN interview with the trained nurse. This interview involved taking of sexual history of the previous 6 months, patient referral using contact slips, abstinence and information about being screened for other STIs. Contact slips included details of the study GUM clinics and requested the treatment centre to return the slip to the study centre. Practise nurses did not follow‐up the index patient Referral to GUM clinic for partner referral from specialist health advisor (n = 68) At randomisation, index patients were referred to GUM clinic. If clinic had not been contacted by telephone within 1 week by index patient, the health adviser made 2 attempts to contact them. PN was performed according to standardised protocols and contact slips were issued. The index patient was also offered a consultation for screening for other STIs. Follow‐up was by telephone
Outcomes	Primary outcome Proportion of index patient with at least 1 sexual partner treated (self report during telephone interview with index patient, or a contact slip returned to the study centre or the partners was confirmed to have attended a local GUM clinic after the index patient received intervention) Number of partners treated per index patient 6 weeks after randomisation (clinic records) Secondary outcomes Number of partners elicited (self report by index patient in sexual history) Proportion of index patients with a positive chlamydia test result 6 weeks after randomisation (urine or vulval swab specimen available) Proportion of index patients with all sexual partners treated (clinic records)
Notes	Ethical approval South West multicentre research ethics committee Only 72 in nurse arm and 47 in clinic arm Study author was contacted to clarify clustering and replied. The author replied that the trial was individually randomised. However, there was often more than 1 participant from a single general practice (i.e. clustering), and it means that there are likely to be similarities between patients within the same practice
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated random numbers, permuted blocks, stratified by practice
Allocation concealment (selection bias)	Low risk	Central computerised telephone system
Incomplete outcome data (attrition bias) All outcomes	Low risk	The PR (nurse) group had PN interview on same day. In PR (GUM) 21/68 (31%) did not attend PN interview. Authors used ITT analysis and assumed those lost to follow‐up were not treated
Selective reporting (reporting bias)	Unclear risk	Protocol available from trial registries. In protocol, adherence to advice to abstain from sexual intercourse until both partners completed treatment was stated as a secondary outcome but not reported in trial. Outcome "Cases with all partners treated" was not prespecified in study protocol but reported
Other bias	Low risk	No other bias identified
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participant and personnel not blinded
Blinding of outcome assessment (detection bias) All outcomes	Low risk	A researcher not involved in the participant's PN did the follow‐up