Client-centred, caseworker-delivered smoking cessation intervention for a socially disadvantaged population.

Current primary outcome measures as of 03/09/2013:
There will be two primary outcome measures obtained at 1 month follow-up:
1. Self-reported quit attempts
2. continuous abstinence
There will be two primary outcome measures obtained at 6 month follow-up:
1. Continuous abstinence
2. 24-hour carbon monoxide (CO) validated self-reported smoking cessation

These follow-up time periods and measures of smoking cessation have been recommended by the Society for Research on Nicotine and Tobacco (SRNT) workgroup for measuring smoking cessation. Continuous abstinence will be defined as abstinent since the 2 week grace period following baseline assessment. Continuous abstinence will allow greater power to detect differences.

Biochemical verification of self-report: General population reports and some clinical trial based studies show that misreporting tends to be low, around 5%. Little is known regarding the misreporting rate of smoking status in this population. Thus, this study will use biochemical validation methods to ensure self-report estimates are validated. Verification will be conducted using measures of CO in expired air as recommended by the SRNT Biochemical Verification workgroup.


Previous primary outcome measures:
There will be two primary outcome measures obtained at 1, 6 and 12 month follow-up:

1. 24-hour carbon monoxide (CO) validated self-reported smoking cessation
2. 7-day self-reported smoking cessation

These follow-up time periods and measures of smoking cessation have been recommended by the Society for Research on Nicotine and Tobacco (SRNT) workgroup for measuring smoking cessation. 7-day smoking cessation will be defined as abstinent for the past 7 days at 1, 6 and 12 months respectively. 7-day point prevalence abstinence is a common and recommended cessation outcome and has the highest concurrent validity of a range of cessation measures including prolonged and continuous abstinence. Also, prolonged abstinence is not an appropriate measure for this sample given the likelihood of delayed intervention effects, high relapse rates and a focus on encouraging repeated quit attempts which should be captured through the use of longer term follow-up (12 months).

Biochemical verification of self-report: General population reports and some clinical trial based studies show that misreporting tends to be low, around 5%. Little is known regarding the misreporting rate of smoking status in this population. Thus, this study will use biochemical validation methods to ensure self-report estimates are validated. Verification will be conducted using measures of CO in expired air as recommended by the SRNT Biochemical Verification workgroup.

1. Sociodemographic characteristics will include:
1.1. Age
1.2. Gender
1.3. Marital status
1.4. Housing status
1.5. Income
1.6. Education
1.7. Postcode.
2. Nicotine dependence will be measured by
2.1. Heaviness of Smoking Index (HSI). HSI scores range from 0-6 and are calculated by summing the points for 1) time to first cigarette smoked after waking (in minutes) and 2) number of cigarettes smoked per day. Higher HSI scores indicate more dependence on nicotine.
2.2. 2-item short form of the Fagerstrom Tolerance Questionnaire
3. Quit attempts. A commonly used item which asks 'How many serious attempts to stop smoking have you made in the last 12 months? By serious attempt I mean you decided that you would try to make sure you never smoked again. Please include any attempt that you are currently making and please include any successful attempt made within the last year'.
4. Use of cessation aids. Clients who have made a serious quit attempt will be asked about treatments they had used in their most recent quit attempt. A single item developed by Shiffman et al will list various pharmacological, behavioural and alternative smoking cessation aids.
5. Partner smoking behaviour. One item will assess partner smoking behaviour: 'Does your partner smoke?' (response options: yes, yes but stopping with me, no ex-smoker, no never smoked, N/A).
6. Depression. A recent meta-analysis indicates that the Patient Health Questionnaire (PHQ) has sensitivity of 80% and specificity of 92% in diagnosing major depression. The two-item PHQ2 is recommended by the US Preventive Services Taskforce for depression screening and will ask 'Over the last 2 weeks have you felt down, depressed or hopeless?' and '...have you felt little interest or pleasure in doing things?'.
7. Financial stress will be measured using a scale developed by Assistant Investigator Prof Mohammad Siahpush et al and previously used as a predictor of smoking behaviour. It includes items asking 'In the last 6 months, did any of the following happen to you because of a shortage of money?' followed by 6 options.