Switching to E-Cigarettes After Type 2 Diabetes Diagnosis and Health Outcomes (E-cig-DM)

Clinical Outcomes Associated With Switching From Combustible Cigarettes to Electronic Cigarettes Among Adults With Newly Diagnosed Type 2 Diabetes: A Nationwide Retrospective Cohort Study

Individuals with T2DM who smoke have higher risks of cardiovascular disease and other complications. Many people consider e-cigarette as a "harm-reduction" alternatives to combustible cigarettes, but it is not clear whether switching to e-cigarettes improves health outcomes in patients with diabetes.

Study Overview

• Status: Completed
• Conditions: Clinical Outcomes; E Cigarette Use; Diabete Type 2
• Intervention / Treatment: Behavioral: Switching to E-cigarette

Detailed Description

Use of electronic cigarettes has increased, partly driven by the perception that they may serve as a "harm-reduction" alternative to combustible cigarettes. Evidence cited in prior work includes higher cessation rates versus nicotine replacement therapy in a randomized trial and reductions in biomarkers of potential harm after switching from combustible cigarettes to e-cigarettes; observational data in high-risk PCI populations have also suggested lower MACCE risk after switching. However, constituents such as nicotine and heavy metals may adversely affect diabetes management, and most prior studies have emphasized potential harms of e-cigarette use itself. As a result, whether switching from combustible cigarettes to e-cigarettes confers a harm-reduction benefit in patients with diabetes remains uncertain. In this regards, the current study evaluated clinical outcomes associated with switching from combustible cigarettes to e-cigarettes in patients with diabetes and to assess whether the degree of switching (partial vs full transition) modifies the risk of adverse clinical events.

• Study Type: Observational
• Enrollment (Actual): 133320

Contacts and Locations

Study Locations

• South Korea
  • Gannam-gu
    • Seoul, Gannam-gu, South Korea, 06351
      • Samsung Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients diagnosed with diabetes from 2018 onward who reported being a "current smoker" at a health examination within the 4 years prior to the diabetes diagnosis, and who could be classified after diagnosis as either continued combustible cigarette smoking ("Current") or e-cigarette use (partial or full transition).

Description

Inclusion Criteria:

• Patients diagnosed with diabetes who reported being a "current smoker" at a health examination within the 4 years prior to the diabetes diagnosis.

Exclusion Criteria:

• age <40 years or ≥75 years
• Pre-existing AMI before diabetes diagnosis
• Pre-existing Revascularization before diabetes diagnosis
• Pre-existing diabetes complications before diabetes diagnosis
• Pre-existing cancer before diabetes diagnosis
• Death within 6 months of the first health examination after diabetes diagnosis
• Cancer within 6 months of the first health examination after diabetes diagnosis

Study Plan

How is the study designed?

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Continued combustible cigarette use; Continued combustible cigarette users after diagnosed DM
Partial Switching to E-cigarette; partial switching to E-cigarette users after diagnosed DM	Behavioral: Switching to E-cigarette; Switching to E-cigarette
Full switching to E-cigarette; fully switching to E-cigarette users after diagnosed DM	Behavioral: Switching to E-cigarette; Switching to E-cigarette

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Rates of MACE	MACE was defined as the composite of all-cause death, MI, and repeat revascularization. The diagnosis of MI was made if patients were hospitalized with primary diagnostic codes related to MI (ICD-10 I21, I22) during follow-up period. In a previous validation study, the accuracy of diagnosis of MI in NHIS data was 93%.16 Unplanned revascularization was defined as presence of procedure codes for percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) after index date.	Up to 5 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Rates of Diabetic complications	Diabetic complications were defined as presence of diabetic neuropathy (ICD-10: E10.4, E11.4, E12.4, E13.4, E14.4, G59.0, G63.2, and G99.0), diabetic foot without amputation (ICD-10: E10.5, E10.7, E11.5, E11.7, E12.5, E12.7, E13.5, E13.7, E14.5, and E14.7), diabetic foot with amputation (ICD-10: E10.5, E10.7, E11.5, E11.7, E12.5, E12.7, E13.5, E13.7, E14.5, and E14.7; procedure codes: N0572-0575), and diabetic retinopathy, including non-proliferative (ICD-10: H360) and proliferative (ICD-10: H360; procedure codes: S5160 and S516) forms.	Up to 5 years
Rates of All-cause death	the individual components of MACE	Up to 5 years
Rates of Myocardial infarction	the individual components of MACE. The diagnosis of MI was made if patients were hospitalized with primary diagnostic codes related to MI (ICD-10 I21, I22) during follow-up period.	Up to 5 years
Rates of Unplanned Revascularization	Unplanned revascularization was defined as presence of procedure codes for percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) after index date.	Up to 5 years
Rates of Ischemic stroke	Stroke was defined based on ICD codes for ischemic stroke (ICD-10 I63, I64) or intracranial hemorrhage (ICD-10 I60-62), combined with the codes for hospitalization.	Up to 5 years
Rates of Hemorrhage stroke	Hemorrhage stroke was defined based on ICD codes for intracranial hemorrhage (ICD-10 I60-62), combined with the codes for hospitalization.	Up to 5 years
Rates of Mild pulmonary disease	Mild pulmonary disease were identified using validated ICD-10 codes.	Up to 5 years
Rates of Severe exacerbation of Pulmonary disease	Hospitalization for exacerbation in patients with a documented pulmonary disease code.	Up to 5 years
Rates of Cancer	Cancer was defined as the presence of cancer-specific insurance claim code (V193 code) with a C code which was an ICD-10 code for cancer.	Up to 5 years

Collaborators and Investigators

• Sponsor: Samsung Medical Center
• Investigators: Principal Investigator: Ki Hong Choi, MD, PhD, Samsung Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2018
• Primary Completion (Actual): December 31, 2023
• Study Completion (Actual): December 31, 2023

Study Registration Dates

• First Submitted: January 22, 2026
• First Submitted That Met QC Criteria: February 10, 2026
• First Posted (Actual): February 17, 2026

Study Record Updates

• Last Update Posted (Actual): February 17, 2026
• Last Update Submitted That Met QC Criteria: February 10, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Smoking; Diabetes mellitus; E-cigarette
• Additional Relevant MeSH Terms: Endocrine System Diseases; Metabolic Diseases; Glucose Metabolism Disorders; Behavior; Nutritional and Metabolic Diseases; Diabetes Mellitus, Type 2; Diabetes Mellitus; Smoking; Vaping
• Other Study ID Numbers: DM_E-cigarette

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No