Caponnetto 2013a.

Study characteristics
Methods	Design: 3‐arm double‐blind randomized controlled trial: EC with 7.2 mg nicotine for 12 weeks; same for 6 weeks followed by 5.2 mg for 6 weeks: EC with no nicotine for 12 weeks Recruitment: Newspaper advertisements Setting: Outpatient clinic, Italy Study start date: April 2010; Study end date:April 2012
Participants	Total N: 300 Inclusion criteria: Smoked at least 10 cpd for past 5 years; Age 18 ‐ 70 In good health Not currently or intending to quit smoking in the next 30 days Exclusion criteria: Symptomatic cardiovascular or respiratory disease Regular psychotropic medicine use Current or past history of alcohol abuse Use of smokeless tobacco or NRT Pregnant or breastfeeding 36% women, mean age 44 (SD 12.5), mean cpd 20 (IQR: 15 ‐ 25) Not currently or intending to quit smoking in the next 30 days E cigarette use at baseline: Not specified
Interventions	EC: Cig‐a‐like EC presented as a healthier alternative to tobacco smoke and could be freely used, ad libitum (up to 4 cartridges a day) for 12 weeks, as a tobacco substitute EC used: 'Categoria' (model 401) with disposable cartridges Grp A: 12 weeks of 7.2 mg capsules ('Original') Grp B: 6 weeks 7.2 mg ('Original'), then 6 weeks 5.4 mg ('Categoria') Grp C: 12 weeks of 0 mg ('Original') Baseline visit and up to 7 follow‐up visits to receive more cartridges, hand‐in diaries, measure CO and vital signs
Outcomes	Abstinence at 12 months (complete self‐reported abstinence from tobacco smoking since previous visit at 6 months, confirmed with CO < 7 ppm at 12 months) ≥ 50% reduction in baseline cigarettes at 12 months Recorded AEs thought to be related to tobacco smoking and EC at baseline and at each study visit (7 follow‐up visits over 12 weeks, plus at 24 and 52 weeks)
Study funding	"This research was supported by a grant‐in‐aid from Lega Italiana AntiFumo. The study sponsor had no involvement in the study design, collection, analysis, and interpretation of data, the writing of the manuscript or the decision to submit the manuscript for publication. RP and PC are currently funded by the University of Catania, Italy. The e‐cigarette supplier had no involvement in the study design, collection, analysis, and interpretation of data, the writing of the manuscript or the decision to submit the manuscript for publication."
Author declarations	"RP has received lecture fees and research funding from Pfizer and GlaxoSmithKline, manufacturers of stop smoking medications. He has served as a consultant for Pfizer and Arbi Group Srl, the distributor of the CategoriaTM e‐Cigarette. The other authors have no relevant conflict of interest to declare in relation to this work."
Notes	Additional data provided from authors
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated, block size 15 (5:5:5 ratio)
Allocation concealment (selection bias)	Low risk	Randomization carried out by pharmacy, who did not have direct contact with the participants
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind. Quote: “Blinding was ensured by the identical external appearance of the cartridges. The hospital pharmacy was in charge of randomization and packaging of the cigarettes”
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Biochemical validation used
Incomplete outcome data (attrition bias) All outcomes	Low risk	211 (70.3%) and 183 (61%) attended 6‐ and 12‐month follow‐up (at 12 m, 35% lost in 7.2 group; 37% lost in 5.4 group; 45% lost in no‐nicotine group)
Selective reporting (reporting bias)	Unclear risk	Unclear if original intention was to combine groups A+B or not. In sample size calculation they compared A+B with C, but results are not always reported in this way