Stein 2016.

Study characteristics
Methods	Design: Non‐controlled open‐label experimental study Recruitment: A flyer posted at a large methadone maintenance treatment programme Setting: Methadone maintenance treatment programme, USA Study start date: April 2015; Study end date: Not specified
Participants	Total N: 12 Inclusion criteria: current moderate or heavy cigarette use (10+ cpd for at least 12 months prior to enrolment) current MMT for at least 3 months ready to make a smoking quit attempt in the next 14 days plan to remain on MMT for at least 12 weeks Exclusion criteria: used e‐cigarettes on more than 2 of the past 30 days currently used medications that may reduce smoking (bupropion, varenicline, NRT) had unstable medical or psychiatric conditions (past‐month suicidal ideation or past‐year suicide attempt, hospitalization for myocardial infarction or stroke in the prior 3 months) had regular use of marijuana (self‐report or positive urine drug test) Inclusion based on specific population characteristic: People receiving MMT for opoid use disorder 50% women; mean age 45.9; mean cpd 17.8; mean FTND: Not reported Motivated to quit: yes E‐cigarette use at baseline: Had not used e‐cigarettes for more than 2 of the past 30 days
Interventions	EC: Cig‐a‐like 2 week supply of NJOY e‐cigarettes at week 1 (quit day), consisting of 5 packs of NJOY e‐cigarettes (15 in total). Participants could request an additional 5 pack (20 in total) for the following 2‐week study period, if they ran out before a study visit. Participants instructed to use EC exclusively for a total of 6 weeks (end of treatment). They were referred to the state telephone QuitLine for supportive counselling at the quit‐day visit (week 1)
Outcomes	Participants quit and received e‐cigs at week 1. Assessments were carried out at week 3, 5, 7 and 9 Adverse events and biomarkers: “Side effects” of e‐cigarettes were recorded. Side effects were rated none, slight, mild, moderate and severe at every assessment visit. An adverse effect possibly related to e‐cigarette use was defined as positive if the value at baseline was either none or slight AND the value at any of 3, 5, or 7 weeks was mild or more severe Other outcomes measured: Reduction in the average cpd E‐cig adherence Nicotine withdrawal
Study funding	“MDS is a recipient of National Institute on Drug Abuse Award K24 DA000512. This award funded the project described here.”
Author declarations	“None declared.”
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	No randomization
Allocation concealment (selection bias)	High risk	No randomization
Incomplete outcome data (attrition bias) All outcomes	Low risk	Quote: “One individual dropped out after week 3 and did not return; another completed all follow‐up assessments except week 7.”
Selective reporting (reporting bias)	Low risk	All expected outcomes reported