An earlier trial conducted in 2005 in New Zealand with 1705 participants and a similar design to the UK study demonstrated the effectiveness of text support.
The main outcome was the prevalence of current non-smoking (not smoking in the past week) six weeks after randomization.
The biochemically verified quit rate for the intervention group receiving text support was 13.9%, whereas it was only 6.2% in the control group (P < 0.0001). That represented approximately one extra quitter for every 13 participants using text support.
While the difference in the 26 week quit rate for the two groups was not statistically significant, the study identified a difference in quit confidence at 26 week follow-up, with 33% of quitters using text support feeling extremely confident they could stay quit compared to only 20% in the control group.
A separate analysis of the same data found that text support was just as effective in the indigenous Maori population as it was in other New Zealanders.
Rodgers A, Corbett T, Bramley D, Riddell T, Wills M, Lin R-B, et al. Do u smoke after txt? Results of a randomised trial of smoking cessation using mobile phone text messaging. Tobacco Control 2005;14:255–261. [: doi: 10.1136/tc.2005.011577]