Methods | 3-armed randomised controlled trial of interactive computer program and telephone counselling to support women to stop smoking in pregnancy Study conducted in a large group model managed care organisation in Los Angeles, California (USA) with recruitment from November 1996 to June 1997 |
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Participants |
Inclusion criteria: Smokers were identified at first visit as women who self-report “smoking now”, “smoke but have cut down since pregnancy”, or “smoke from time to time” Exclusion criteria: < 18 years of age, > 26 weeks’ gestation, do not speak English, or smoked less than 7 cigarettes pre-pregnancy Recruitment: Researchers attempted to phone 931 women. 150 could not be contacted, 90 refused to be interviewed, 158 were not eligible and 34 were excluded as they experienced miscarriage (n = 34). 390/458 women (82%) agreed to participate (C = 131, I1 = 133, I2 = 126). Baseline characteristics: Pre-pregnancy mean cigs per day: C = 17.1 (9.7), I1 = 17.6 (9.8), I2 = 16.3 (7.6). Mean cigs per day at intake: C = 6.6(7.3), I1 = 6.7(6.5), I2 = 6.3 (6.5). 60% white, approximately 50% college educated, with a mean age of 29.4. Mean cigarette/day at first visit = 6.6 Progress+ coding: None. |
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Interventions | 3 interventions, based on stages of change model. Control: Received a 32-page self-help booklet “living smoke-free”. Intervention 1 (interactive computer program-IVR): received the same self-help booklet and had access to a computerised interactive telephone support system, which provided customised messages from a voice model. Participants responded to questions using a touch-tone keypad. Intervention 2 (motivational interviewing): received the same self-help booklet and 4-6 × 10-15 minute telephone counselling sessions by nurse educators trained in motivational interviewing. A personalised postcard sent to reinforce verbal communication Main intervention strategy: Counselling (single intervention) compared to a less intensive intervention (self-help booklet). Arms 1 and 3 only are compared in this review Intensity: Frequency (C = 2, I = 6), Duration (C = 1, I = 3). Intervention provided by study staff: efficacy study. |
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Outcomes | Biochemically validated smoking cessation at 34 weeks’ gestation (late pregnancy*). Mean cigarettes per day* Baseline mental health index and Cohen’s perceived stress scale. Number of quit attempts and movement in stages of change. |
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Notes | ||
Risk of bias | ||
Bias | Authors’ judgement | Support for judgement |
Random sequence generation (selection bias) | Unclear risk | Described as “random assignment” |
Allocation concealment (selection bias) | Unclear risk | No information. |
Incomplete outcome data (attrition bias) All outcomes |
Unclear risk | Attrition 58/390 (14.87) due to abortion (n = 31), disenrolment from health plan (n = 22) and preterm birth less than 32 weeks (n = 5). Lost to follow-up not included as continuing smokers in analysis as attrition due to medical reasons and moving not reincluded in this review, and attrition from each study group not reported separately |
Selective reporting (reporting bias) | Unclear risk | Results were difficult to interpret. |
Other bias | Low risk | No other bias detected. |
Biochemical validation of smoking abstinence (detection bias) | Low risk | Biochemical validation by urinary cotinine levels (< 80 ng/mL) |
Blinding of participants and personnel (performance bias) All outcomes |
Unclear risk | Authors state that care providers were blind to group allocation. Educational intervention so blinding women not feasible |
Blinding of outcome assessment (detection bias) All outcomes |
Unclear risk | Not reported |
Incomplete implementation | Low risk | Good process evaluation of each of the methods. 79.2% received at least 1 call. Mean 4 calls lasting 12 mins each |
Equal baseline characteristics in study arms | Low risk | No significant differences reported. |
Contamination of control group | High risk | 11% control group received individual smoking cessation counselling as they were classified as high risk patients |