Condition category
Nutritional, Metabolic, Endocrine
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status
Results overdue

Plain English Summary

Background and study aims
Growing evidence suggests that smoking has a substantial impact on patients with diabetes, but smoking cessation (quitting smoking) is largely ignored in routine diabetic care. The aim of this study is to test the effectiveness of a tailored smoking cessation intervention to improve the quit rate and the control of blood sugar levels of smoking type 2 diabetic patients.

Who can participate?
Smoking type 2 diabetic patients aged 18 or over.

What does the study involve?
Participants complete a lifestyle questionnaire and their exhaled carbon monoxide level is measured (this indicates how much they smoke). They are then randomly allocated to either the intervention group or the control group. The intervention group receive education materials about smoking cessation and a 30-minute face-to-face counselling session. The control group receive leaflets about diabetes management and a self-help smoking cessation guide. Counselors contact both groups 1 week and 1 month later. Participants are also contacted regularly after 3, 6 and 12 months. At the 12-month follow-up, saliva samples and exhaled carbon monoxide are collected from participants who successfully quit smoking or reduce their cigarette consumption by at least 50%.

What are the possible benefits and risks of participating?
This study is completely safe and will not cause any discomfort. All information gathered is confidential. Individuals’ names will not be used during data analysis nor identified when the results are reported.

Where is the study run from?
This study is conducted by the School of Nursing and Department of Community Medicine, School of Public Health, of the University of Hong Kong with the Hospital Authority of the Hong Kong government. About 10 diabetes specialty outpatient clinics under the Hong Kong Hospital Authority will be participating in this study. Six confirmed clinics are listed below:
Caritas Medical Centre, Diabetes Care Centre
Tung Wah Eastern Hospital, DM Centre
Queen Mary Hospital, DM Centre
Pok Oi Hospital, DM Centre
United Christian Hospital, Diabetes Ambulatory Care Centre
Ruttonjee Hospital, Diabetes Centre

When is the study starting and how long is it expected to run for?
January 2011 to June 2013.

Who is funding the study?
Hong Kong Health and Health Services Research Fund

Who is the main contact?
Prof. Sophia Chan

Trial website

Contact information



Primary contact

Prof Sophia SC Chan


Contact details

The Univeristy of Hong Kong
Li Ka Shing Faculty of Medicine
4/F William MW William Block
21 Sassoon Road
Hong Kong

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

A randomized controlled trial of a tailored intervention compared to usual care on smoking type 2 diabetic patients to promote smoking cessation and improved glycaemic control


Study hypothesis

To test the effectiveness of a tailored smoking cessation intervention targeting type 2 diabetic patients who smoke in achieving:
1. Smoking cessation and/or improvement in smoking behaviours
2. A better control of HbA1c level
3. Predictive factors for the success of the two primary outcomes and
4. Cost-effectiveness of the intervention compared to the control

Ethics approval

Institutional Review Board of the University of Hong Kong/ Hospital Authority Hong Kong West Cluster, 22/4/2008, ref: UW 08-142

Study design

Multicentre single-blinded randomized controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting

GP practices

Trial type

Quality of life

Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Type II diabetes


The intervention group will receive education materials about smoking cessation, and a 30-minute face-to-face smoking cessation counselling conducted by a trained nurse smoking cessation counsellor at baseline. A 20-minute follow up phone counselling will be provided at 1-week and 1-month after recruitment.

The control group will receive leaflets on diabetes management and self-help smoking cessation guide.

Intervention type



Not Applicable

Drug names

Primary outcome measure

Self-reported 7-day tobacco abstinence rate at 12 months

Secondary outcome measures

1. The change in glycated haemoglobin (HbA1c) levels
2. Biochemical validated quitting and changes in smoking behaviors (reduction in cigarette consumption and progression to a higher stage of readiness to quit)
3. Clinical outcomes [body mass index (BMI), sodium, potassium chloride, blood glucose, blood pressure and renal function] and
4. Lifestyle risk factors (drinking, fruit and vegetable intake)

Measured at 12 months

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Smokes at least 2 cigarettes daily in the past 30 days
2. Diagnosed with type 2 diabetes for at least 6 months such that their diabetic conditions and treatments should be stable
3. Age 18 or above
4. Can communicate in Cantonese

Participant type


Age group




Target number of participants

379 patients will be required in each group to achieve a significant outcome. Hence the total sample size of the study will be 758 (DM and Control groups).

Participant exclusion criteria

1. Too sick to receive intervention
2. Poor cognitive state
3. Mental illness
4. Undergoing other smoking cessation program
5. With unstable diabetic or other medical conditions deemed to be not suitable by the doctor in charge

Recruitment start date


Recruitment end date



Countries of recruitment

Hong Kong

Trial participating centre

The Univeristy of Hong Kong
Hong Kong

Sponsor information


Hong Kong Health and Health Services Research Fund (Hong Kong)

Sponsor details

Research Fund Secretariat
Research Office
Food and Health Bureau
Murray Building
Garden Road
Hong Kong

Sponsor type




Funder type


Funder name

Hong Kong Health and Health Services Research Fund (Hong Kong) (Ref: 08091061)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes