Smartphone app and carbon monoxide self-monitoring support for smoking cessation: A randomised controlled trial nested into the Swiss HIV Cohort Study. Â JAIDS
Gryaznov et al. investigated whether exhaled carbon monoxide (CO) self-monitoring in conjunction with a smoking cessation app may improve smoking cessation in HIV-positive smokers.
They nested a randomized controlled into the Swiss HIV Cohort Study and randomly allocated during biannual cohort visits patients smoking ≥3 cigarettes a day via a trial website to counselling by SHCS center physicians (usual care) or to a combined intervention of CO self-monitoring with mobile phone-based feedback and app-based smoking cessation support.
At the start of the trial on June 1, 2017, 3’293 of 10’493 (34%) patients in the SHCS smoked ≥3 cigarettes and these 2’444 (74%) indicated at any cohort visit in the previous 48 months to have quit once and then resumed smoking. During a recruitment period of 1.5 years, 1’807 patients were screened for inclusion and a total of 81 patients were enrolled. Six of 42 (14%) participants in the intervention group and 5 of 39 (13%) in the standard of care group quit smoking at 6 months follow-up (adjusted odds ratio 1.06, 95% CI: 0.29 to +3.86) and 3 participant were lost to follow-up. Based on the 12-month cohort data, one individual had resumed smoking and 5 trial participants reported to have quit smoking. The adjusted mean difference in smoked cigarettes between the intervention and control groups at 6 months was −1.38 (95% CI: −4.45 to 1.69).
In conclusion, results from this pragmatic trial remained inconclusive and underpowered because of recruitment difficulties, although the nested trial design allowed for the potential to recruit from a large group of smokers with a self-reported history for quitting. Patients included in the trial reported more cessation attempts which was identified as the best predictor for successful quitting from observational data analysis of the SHCS. This information, however, did not translate into a high recruitment rate. Overall, 11% of the trial population – irrespective of the intervention – quit, which is considerably higher than the 1.6% smokers in the remaining cohort who had indicated to have quit.