Characteristics of included studies [ordered by study ID]
| Dogar 2014 | ||
| Methods | Year(s) of study: 2010 – 2011 Study design: 3-arm cluster-randomized controlled non-inferiority trial Country: Pakistan Region: Jhang and Sarghoda districts Setting: 33 primary and secondary health centres Theoretical framework: based on the World Health Organization’s ‘5As Approach’ |
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| Participants | Adults aged over 18 years with suspected tuberculosis (cough ≥ 3 weeks, of unknown cause) Excluded: those requiring hospitalization or urgent medical attention Recruitment method: patients attending primary and secondary healthcare centres registered as diagnostic centres by a tuberculosis program in 2 Pakistani districts 33 clusters, 200 adults Mean age 51.5 (SD 13.8), median household income USD 81.4 (IQR 69.8), 21% women Definition of smoking status: ≥ 1 waterpipe/day |
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| Interventions | Focus of intervention: any smoking use Type of intervention: behavioural and pharmacological Description of the intervention: Control group: given a leaflet with standard health messages about the harms of tobacco Intervention group 1: 2 brief behavioural support cessations (1st visit 30 mins, 2nd on quit day 10 mins) Intervention group 2: 2 brief behavioural support cessations (as above) plus bupropion for 7 weeks (75 mg/day for 1st week, 150 mg/day for next 6 weeks) Intervention delivered by: tuberculosis DOTS (directly observed treatment, short course) paramedics |
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| Outcomes | Continuous waterpipe smoking abstinence Length of follow-up: six months Biochemical validation: CO verified (< 10 ppm) |
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| Notes | Differential effects post-intervention: none reported Adverse effects of intervention: none reported The study was funded by the International Development Research Centre, Canada |
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| Risk of bias | ||
| Bias | Authors’ judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Not mentioned in sufficient detail in this paper; full trial methodology found in Siddiqi 2013 Quote: “a researcher who was blinded to center identity used computer-generated random-number lists to generate allocation sequence” Comment: probably done |
| Allocation concealment (selection bias) | Low risk | Not mentioned in sufficient detail in this paper; full trial methodology found in Siddiqi 2013: Quote: “a researcher who was blinded to center identity used computer-generated random-number lists to generate allocation sequence” Commment: probably done |
| Blinding of participants and personnel (performance bias) All outcomes |
High risk | Not mentioned in this paper; full trial methodology found in Siddiqi 2013: Quote: “the lack of blinding also meant that a degree of observer bias was possible” Comment: probably not done |
| Blinding of outcome assessment (detection bias) All outcomes |
Low risk | Not mentioned in this paper; full trial methodology found in Siddiqi 2013: Quote: “the lack of blinding also meant that a degree of observer bias was possible” Comment: outcome measurement is biochemically verified, and is unlikely to be affected by blinding |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Primary outcome data missing for 7.0% of waterpipe-only smokers. Reasons for missing data unlikely to be related to true outcome. No exclusions reported |
| Selective reporting (reporting bias) | High risk | Outcomes not reported at 5 weeks |
| Other bias | Low risk | Biochemical verification of outcome |
| Lipkus 2011 | ||
| Methods | Year(s) of study: 2009 – 2010 Study design: randomized controlled web-based behavioural intervention Country: USA Region: North Carolina Setting: 6 college and university campuses Theoretical framework: none reported |
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| Participants | Adults enrolled in a 4-year college or university course Recruitment method: newspaper advertisements, flyers posted around campuses, Craig’s list, campus-wide Listserv 91 adults Mean age 20.4 (SD 2.0), 24.2% women, 76.7% white Definition of smoking status: past-month waterpipe smoking |
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| Interventions | Focus of intervention: waterpipe smoking Type of intervention: behavioural Description of the intervention: Control group: 8 MS PowerPoint slides on waterpipe mechanism of action, chemical composition, and epidemiology; average length of intervention 3.6 minutes Intervention group: 20 MS PowerPoint slides on waterpipe mechanisms of action, chemical composition, epidemiology, puff topography, toxicant exposure, and health outcomes; average length of intervention 7.5 minutes Intervention delivered by: online |
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| Outcomes | Ticking the survey item: “no longer smoking waterpipe” Length of follow-up: 6 months Biochemical validation: not present |
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| Notes | Differential effects post-intervention: none reported Adverse effects of intervention: none reported The study was funded by grants from the US National Cancer Institute and National Institute on Drug Abuse |
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| Risk of bias | ||
| Bias | Authors’ judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Quote: “those who logged on were randomized to either a control or an experimental group with equal probability by our program” Comment: probably done |
| Allocation concealment (selection bias) | Unclear risk | No information on allocation concealment Comment: insufficient confidence that allocation concealment was adequate |
| Blinding of participants and personnel (performance bias) All outcomes |
Unclear risk | No information on blinding Comment: insufficient confidence that blinding was adequate |
| Blinding of outcome assessment (detection bias) All outcomes |
High risk | No information on blinding Comment: outcome measurement not biochemically verified |
| Incomplete outcome data (attrition bias) All outcomes |
Low risk | 23.1% of participants did not conduct the 6-month follow-up. Unlikely to be related to outcome. No reasons given for loss to follow-up. 1 participant in the 6-month follow-up had missing data and was not analysed. No exclusions reported |
| Selective reporting (reporting bias) | High risk | Cessation data not appropriately presented as effect estimates |
| Other bias | High risk | No biochemical verification of outcome |
| Mohlman 2013 | ||
| Methods | Year(s) of study: 2004 – 2005 Study design: cluster-randomized controlled behavioural intervention Country: Egypt Region: Qalyubia governorate Setting: Villages Theoretical framework: None reported |
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| Participants | All household members aged over 12 years old, although results pertain only to adult men (n of women for self-reported smoking too small); Waterpipe smokers: Intervention villages 250, control villages: 290 Recruitment method: Systematic approach of households 6 clusters, 7657 residents Mean age 36.9, 41.8% illiterate, 87.3% employed, 55.3% women Definition of smoking status: Past-month waterpipe smoking |
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| Interventions | Focus of intervention: cigarettes and/or waterpipe smoking Type of intervention: behavioural Description of the intervention: educational approach for primary/preparatory/secondary school students, mosques and churches, and key female social change agents (raedat refeyat) Intervention delivered by: teachers, religious leaders, female social change agents Control group: no intervention |
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| Outcomes | Waterpipe smoking prevalence Length of follow-up: 12 months Biochemical validation: not present |
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| Notes | Differential effects post-intervention: none reported Adverse effects of intervention: none reported The study was funded by the Fogarty International Center of the US National Institutes of Health |
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| Risk of bias | ||
| Bias | Authors’ judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: “the remaining six villages were randomly allocated to either the control group or the intervention group” Comment: insufficient confidence that the allocation sequence was genuinely randomised |
| Allocation concealment (selection bias) | Unclear risk | No information on allocation sequence Comment: insufficient confidence that allocation concealment was adequate |
| Blinding of participants and personnel (performance bias) All outcomes |
Unclear risk | No information on blinding Comment: insufficient confidence that blinding was adequate |
| Blinding of outcome assessment (detection bias) All outcomes |
High risk | No information on blinding Comment: outcome measurement is not biochemically verified |
| Incomplete outcome data (attrition bias) All outcomes |
Low risk | 77.5% retention rate. Women excluded due to very low self-reporting of tobacco use. All completed pre-intervention survey but not all completed post-intervention survey. No reasons given for loss to follow-up |
| Selective reporting (reporting bias) | High risk | Cessation data not appropriately presented as effect estimates |
| Other bias | High risk | No biochemical verification of outcome |