The Effect of Re-randomization in a Smoking Cessation Trial

The purpose of this sub-study was to determine whether operating engineers (heavy equipment operators) who failed to quit smoking in a randomized controlled trial would benefit from re-exposure to the interventions one year later.

Operating Engineers attending workplace safety training groups during the winters of 2010 to 2012 were randomized by training group to either to the Tobacco Tactics Web-based intervention or the 1-800-QUIT-NOW telephone line. Of the 145 original participants, 41 reappeared in training groups one year later and were re-randomized with their group. Seven-day point prevalence quit rates at 30-days and 6-months post-intervention were analyzed using the chi-square test and Fisher's exact test.

At 30-day follow-up, an additional 9.8% (4/41) of repeaters had quit smoking. At 6-month follow-up, 12.2% (5/41) of repeaters had quit smoking. At 30-day follow-up, increased quitting was more common among those re-randomized to the intervention group than among those who received the control treatment, although this was not statistically significant and was no longer true at 6-month follow-up.

Because many smokers make multiple attempts to quit smoking, re-enrollment of participants in smoking cessation trials may produce additional quitters.