Chen 2014.

Methods	Study design: Randomied controlled trial Setting: Hospital, China Recruitment: community volunteers and referrals from outpatient clinics
Participants	190 smokers, > 1 cpd, 97% men, av.age 50, av. cpd 20. All had lung function tests; 85 had COPD and 105 were asymptomatic
Interventions	Therapist: "Interventions provided by 2 doctors with experience of professional smoking cessation treatment." 1. Cognitive counselling, 20 mins at baseline and 9 calls > 10 mins at 1 ‐ 4 wks, 6 wks, 8 wks, 3 ‐ 5 m. S‐H materials 2. Brief advice
Outcomes	Abstinence at 6 m sustained from week 4 Validation: CO < 10 ppm
Notes	New for 2016 update
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"assigned to the intervention or control group according to the randomized digital table" stratified by motivation to quit
Allocation concealment (selection bias)	Unclear risk	No further details
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Biochemical validation of abstinence
Incomplete outcome data (attrition bias) All outcomes	Low risk	12 withdrawals included as smokers