Sundblad 2008.

Methods	Design Randomised controlled trial Setting Outpatients
Participants	Inclusion criteria COPD (according to ERS guidelines), smoked more than 8 cigarettes/day, aged 40 to 60 years, lived in or in the vicinity of 9 Swedish towns and cities. Exclusion criteria Linguistic difficulties, severe comorbidities, or inability to stay away from home or work (either through reluctance or practical considerations). Number randomised Total 478, smoking cessation group (SC) 247, control group 231 Number followed up Total 391 Age mean (range): SC 53 (41 to 62), control 52 (41 to 61) Sex n (%) male: SC 111 (45), control 109 (47) Cigarettes/day mean (SD): not reported FTND mean (SD): SC 4.7 (2.0), control 4.8 (2.0) Severity COPD (FEV1/FVC not reported) FEV1% predicted, mean (SD): SC 74 (16), control 77 (14)
Interventions	Behavioural treatment A. Smoking cessation Preparation time at home (2 weeks); registration of craving of cigarettes and number of smoked cigarettes; try reducing smoking by 25% Hospitalisation: 11 days in groups of 4 to 10 members (third day, cessation day); use of NRT was recommended; physical exercise; 1‐hour daily meeting with trained cessation nurse (individual counselling); structured educational program (topics: nicotine, health effects, dietary, training, lung function testing by doctor, physiotherapist, dietitian, technician, psychologist, occupational therapist, nurse) (group counselling); registration of craving, coping strategies, number of cigarettes At home: 2 to 3 months; registration with feedback: craving, coping strategies, number of cigarettes (telephone counselling, 1 weekly 5 to 30 min per call) Hospitalisation: 2 to 4 days; spouses invited; group discussions with the spouses: how to sustain smoking abstinence and avoid relapse At home: 10 months; registration with feedback of craving, coping strategies, number of cigarettes (telephone/email counselling) B. Control Participants in the usual‐care group were referred to primary healthcare centres and were informed about the COPD diagnosis and that smoking cessation had been recommended. Pharmacological treatment A. Smoking cessation Use of NRT was recommended B. Control Not specifically recommended
Outcomes	Abstinence Point prevalence abstinence at 1 and 3 years from start of the intervention Validation Exhaled CO < 8 ppm, tested at 3 years' follow‐up, in a random sample of quitters
Notes	Funding The study was supported by the research department of AFA Insurance Company, Stockholm, Sweden Conflicts of interest Not reported Correspondence Additional information received after correspondence
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"According to a prearranged schedule, subjects were assigned into two groups by a person outside the study either to participate in the smoking cessation program or to be in a control group receiving usual care." A computer‐generated randomisation list was used. (Additional information from author)
Allocation concealment (selection bias)	Low risk	The allocation of participants to active treatment or control was totally concealed; when a participant was to be randomised, a phone call was made to an external person in a different location who picked the next number from his pre‐generated randomisation table. (Additional information from author)
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not possible to blind for behavioural treatment
Blinding of outcome assessment (detection bias) All outcomes	High risk	The assessment of smoking abstinence was open and based on self reporting. However, in a random sample of approximately 50% of those who stated they were abstinent, an open (both study participant and personnel) carbon monoxide measurement was performed. (Additional information from author)
Incomplete outcome data (attrition bias) All outcomes	High risk	Differential attrition
Selective reporting (reporting bias)	Low risk	All prespecified outcomes were reported
Other bias	High risk	A. Participants' and personnel's adherence to the intervention protocol was not clearly described. It is only reported that "the one year long intervention followed a detailed protocol and the care providers did not change during the study." (Additional information from author) B. Exhaled CO was tested at 3 years' follow‐up in a random sample of quitters