Schillinger 2003.

Methods	Setting: FPCs (Southern California (SC), Seattle (S) and New Orleans (NO)), adolescent clinics (Birmingham (B), Indianapolis (I), Northern California (NC) and S), primary care clinics (I) and STD clinics (B, I, NO, SC, NC, S) or emergency and other hospital departments (B), US Enrolment: participants enrolled between September 1996 and June 2000 Follow‐up: index patients returned for a follow‐up at 1 and 3 months after enrolment for an interview and urine test
Participants	1889 index patients with laboratory confirmed Chlamydia trachomatis were randomised Inclusion criteria Women Aged 14‐34 years Laboratory‐confirmed uncomplicated urogenital chlamydial infection Exclusion criteria Already been treated No intercourse in 60 days before enrolment Male partners already been treated for chlamydia Pregnant HIV infected Co‐infected with Neisseria gonorrhoeae, Treponema pallidum or Trichomonas vaginalis History of adverse reaction to macrolide antibiotics
Interventions	At enrolment all women were treated for chlamydia infection and were advised to abstain from intercourse until 7 days after partner's treatment Simple patient referral (n = 943) Index patients were instructed to tell their partners that they had been exposed to chlamydial infection and to recommend that they seek treatment. They were given an information sheet for each partner and list of clinics where the partner could obtain free care EPT (n = 946) Index patients were provided with up to 4 doses of medication for their partners, instructed to tell their partners of their exposure, and to give a package with the medication, instructions, warnings, fact sheet on chlamydia and telephone number to contact if partners had any questions. Index patients were advised to abstain from intercourse until 7 days after each partner's treatment
Outcomes	Re‐infection with C. trachomatis in index patient measured by DNA in urine collected 21 days or more after treatment for initial infection (laboratory results)
Notes	Ethical approval by investigational review boards at each of participating institutions and the CDC Limited power as only 1454 participants completed study to 1 follow‐up. With 0.05 significance, this study only had 62% power to detect a 30% reduction in infection. For a 20% difference in infection rate (as was observed in this study), there was only 37% power to detect a significant difference between 2 interventions. In order to have 80% power, need 2035 women in each arm
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Study allocations were made with use of "randomly sized blocks"
Allocation concealment (selection bias)	Low risk	Study arm assignments were printed on cards and placed in sequentially numbered, opaque envelopes and sealed at the study co‐ordination centre
Incomplete outcome data (attrition bias) All outcomes	Low risk	1454/1787 (81%) participants came for at least 1 follow‐up visit and gave a urine sample for the outcome measure. There was a similar proportion in each study arm. ITT was not followed because index patients who did not return for follow‐up or for whom no urine test result existed were excluded
Selective reporting (reporting bias)	Low risk	Outcomes reported in methods section were reported in results section. Protocol not available from 3 trial registries
Other bias	Low risk	No other bias identified
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding was not possible
Blinding of outcome assessment (detection bias) All outcomes	Low risk	1 month after treatment, women were interviewed again and urine tested with LCx/PCR. Assessor knew assignment but outcome measure was objective