Bastian 2013.

Methods	Study design: RCT Location: USA Setting: telephone support Recruitment: lung cancer patients identified relatives and friends who smoked through four clinical sites. A letter was written to the friend/relative explaining the study and asking them to call a toll‐free number if they wanted to decline participation. Those who did not decline were called by the study team seven days later to assess eligibility.
Participants	Defining eligibility criteria?: in social network/family of someone diagnosed with lung cancer Participant characteristics: 496 adult smokers, randomised to intervention (245) control (251). 58% female. Mean age 47, mean cpd 19.5. Motivation to quit?: not selected on motivation
Interventions	Control: self‐directed materials: letter from an oncologist encouraging participants to give up smoking, quit kit (including an ALA cessation guide, straws, candy, cards, and a notepad), and an individually‐tailored information booklet. Mailing of 2‐week nicotine patch starter kit and advised to call for a further 2‐week supply as needed Intervention: As control, plus 6 weekly telephone calls over the 12‐week intervention period ‐ standard smoking cessation counselling using MI techniques and adaptive coping skills training Provider: counsellors Intensity: 1 x 30‐minute session a week for 6 weeks Was MI fidelity monitored?: not reported
Outcomes	Definition of cessation used: 7‐day PPA Length of longest follow‐up: 12 months Validation: none Was mental health and/or well‐being measured at follow‐up?: no Was quality of life measured at follow‐up?:no
Funding source	Supported by the National Cancer Institute grant 5U01‐CA‐92622, also in part by the Intramural Program of the National Human Genome Research Institute, National Institutes of Health
Author conflicts of interest	Not reported
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Randomization was blocked by patient, with entire social network units stratified by site and size of social network enrolled (one vs. two or more) assigned to the same condition." No further information given
Allocation concealment (selection bias)	Unclear risk	Quote: "Randomization was blocked by patient, with entire social network units stratified by site and size of social network enrolled (one vs. two or more) assigned to the same condition." No further information given
Blinding of outcome assessment (detection bias) All outcomes	High risk	Quote: "We attempted to verify self‐report cessation at 2 weeks, 6 months and 12 months postintervention with saliva cotinine analysis, but were unable to do so because return rates (via mail) for saliva samples were low". Therefore, quit rates were not validated and the amount of support differed between arms.
Incomplete outcome data (attrition bias) All outcomes	High risk	136/245 lost to follow‐up in intervention arm; 132/251 lost to follow‐up in control arm. Therefore, loss to follow‐up was high (more than 50%).