Polosa 2011

Methods	Design: Prospective cohort Recruitment: Advertisments in local hospital in Catania, Italy Inclusion criteria: Healthy smokers 18 ‐ 60 years old, smoking ≥ 15 cpd for at least the past 10 years, and not wanting to quit smoking at any time in the next 30 days Exclusion criteria: History of alcohol and illicit drug use, psychiatric illness, recent myocardial infarction, angina pectoris, high blood pressure (BP > 140 mmHg systolic or 90 mmHg diastolic, or both), diabetes mellitus, severe allergies, poorly‐controlled asthma or other airways diseases
Participants	Total N: 40, hospital staff 35% women, mean age 42.9 (SD 8.8), median cpd 25 (IQR 20 ‐ 30), median FTND 6.0 (IQR 6 ‐ 8)
Interventions	Seen at baseline, given EC ('Categoria' brand) with an initial 4‐week supply of 7.4 mg nicotine cartridges. Instructed to use ad libitum up to 4 cartridges per day. EC cartridges supplied at months 1, 2, and 3 No instruction on cessation or reduction was provided
Outcomes	Follow‐up at 1, 2, 3, 6, 18 and 24 months where cigarette consumption, CO, and AEs were measured, incl. 30‐day PP CO‐validated abstinence at 6 months and CO‐validated abstinence at 18 & 24 months (not otherwise defined) Adverse events
Notes	Smoking cessation services provided to those who spontaneously asked for assistance with quitting. These participants were excluded from the study protocol
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Prospective cohort
Allocation concealment (selection bias)	High risk	Not randomized
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Biochemical validation
Incomplete outcome data (attrition bias) All outcomes	Low risk	13/40 were lost to follow‐up, but used ITT analysis
Selective reporting (reporting bias)	Unclear risk	Unable to determine prespecified outcomes