Ikonomidis 2020a.

Study characteristics
Methods	RCT Recruitment: Smoking cessation clinic of second cardiology department of National and Kapodistrian University of Athens, Attikon General Hospital Setting: Hospital smoking‐cessation unit, Greece Study start date: NS
Participants	N = 40; Arm 1 E‐cigarette n = 20; Arm 2 conventional tobacco cigarette n = 20 80% female; mean age 44.8 (SD 11.3); mean cpd: 25.8 (C‐cig 25.5 SD 9.3. E‐cig: 26.2 SD 9.1) Inclusion criteria: smokers without cardiovascular disease, who used to smoke 25.8 ± 9.2 conventional cigarettes per day of their choice Exclusion criteria: abnormal renal function hepatic failure (bilirubin > 2 mg/dl) active malignancy people treated with drugs that affect platelet function history of coronary artery disease or peripheral artery disease history of cardiomyopathy age < 21 years old people with thrombocytopenia (PLTs < 100 × 109 /L) anemia (HCT < 28%) alcohol or drug abuse pregnancy risk factors for cardiovascular disease
Interventions	EC: Refillable E‐cig: second‐generation e‐cig device and popular in Greek Market e‐liquid (NOBACCO eGo Epsilon BDC 1100, eGo battery, 1100 mAh, operating at 3.9 V ‐ propylene glycol 74.3%, glycerin 20%, flavoring 4.5%, nicotine 1.2%/12 mg/ml)
Outcomes	Baseline, 4 months: Exhaled CO concentration; blood pressure Also, cpd; Ppatelet function by Platelet Function Analyzer PFA‐100 and Light Transmission Aggregometry; Pulse wave velocity; Plasma malondialdehyde levels as oxidative stress index
Study funding	"There was no funding for this study"
Author declarations	"The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper."
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Table of random numbers as reproduced from the online randomization software www.graphpad.com/quickcalcs/index
Allocation concealment (selection bias)	Unclear risk	Not specified
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not possible
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Only CO outcomes used here, which are objectively measured
Incomplete outcome data (attrition bias) All outcomes	Low risk	All followed up (confirmed via contact with authors)
Selective reporting (reporting bias)	Unclear risk	No protocol or clinical trial record available to confirm whether all prespecified criteria were reported