Table 2.
Ítem | Daughton et al (1998) | Grandes et al (2000) | Torrecilla et al (2001) | Twardella et al (2007) | Secades-Villa et al (2009) |
---|---|---|---|---|---|
1. The study addresses an appropriate and clearly focused question? | Yes | Yes | Yes | Yes | Yes |
2. The assignment of participants to treatment groups is randomised? | Yes | No | Yes | Yes | Yes |
3. An adequate concealment method is used | Yes | Yes | Can't say | Can't say | Can't say |
4. Participants and investigators are kept ‘blind’ about treatment allocation | Yes | No | Can't say | No | Can't say |
5. The treatment and control groups are similar at the start of the trial | Yes | Yes | Yes | Yes | No |
6. The only difference between groups is the treatment under investigation | Yes | Yes | Yes | Yes | Yes |
7. All relevant outcomes are measured in a standard, valid and reliable way | Yes | Yes | Yes | Yes | Yes |
8. What percentage of the individuals or clusters recruited into each treatment arm of the study dropped out before the study was completed? | 1.1% at 3 months, 1.6 at 6 months and 2.2% at 1 year | Control group: 1.8% Intervention group: 4.6% |
CG: 6% Isolated advice :3% NRT: 7.7% |
CG:19% The interventions 14–17% |
1.2% |
9. All the participants are analysed in the groups to which they were randomly allocated (often referred to as intention-to-treat analysis) | Yes | Yes | Yes | Yes | Yes |
10. Where the study is carried out at more than one site, results are comparable for all sites | Yes | Yes | Does not apply | Yes | Does not apply |
11. How well was the study done to minimise bias? | Acceptable | Acceptable | Acceptable | Acceptable | Acceptable |
12. Taking into account clinical considerations, your evaluation of the methodology used, and the statistical power of the study, are you certain that the overall effect is due to the study intervention? | Yes | Yes | Yes | Yes | Yes |
Ítem | Ramos et al (2010) | Cabezas et al and Puente et al (2011) | Lou et al (2013) | Smit et al (2013) |
---|---|---|---|---|
1. The study addresses an appropriate and clearly focused question? | Yes | Yes | Yes | Yes |
2. The assignment of participants to treatment groups is randomised? | Yes | Yes | Yes | Not clear |
3. An adequate concealment method is used | Yes | Yes | No | Yes |
4. Participants and investigators are kept ‘blind’ about treatment allocation | Yes | No | No | No |
5. The treatment and control groups are similar at the start of the trial | Yes | Yes | Yes | Yes |
6. The only difference between groups is the treatment under investigation | Yes | Yes | Yes | Can't say |
7. All relevant outcomes are measured in a standard, valid and reliable way | Yes | Yes | Yes | Yes |
8. What percentage of the individuals or clusters recruited into each treatment arm of the study dropped out before the study was completed? | CG: 76% IG1: 69% IG2:72% | CG:44.8% IG: 43.3% | CG: 28.9% IG: 23.2% | 44.2% in general, no available information by group |
9. All the participants are analysed in the groups to which they were randomly allocated (often referred to as intention-to-treat analysis) | Yes | Yes | Yes, see ítem 12 | Yes |
10. Where the study is carried out at more than one site, results are comparable for all sites | Does not apply | Can't say | Yes | Can't say |
11. How well was the study done to minimise bias? | Acceptable | Acceptable | Acceptable | Acceptable |
12. Taking into account clinical considerations, your evaluation of the methodology used, and the statistical power of the study, are you certain that the overall effect is due to the study intervention? | Yes | Yes | Only on those individuals followed at least 1 month | Not clear, since a higher percentage of younger participants were lost |
CG, control group; IG, intervention group; NRT, nicotine replacement treatment; SIGN, Scottish Intercollegiate Guidelines Network.