Stratification, Randomization, and Blinding
After enrollment, participants were stratified by medication choice. Using FDA information, participants were asked to choose between using nicotine patches or varenicline. After stratification, participants in the varenicline and nicotine patch groups were randomized 1:1 to adaptive treatment or standard treatment groups. Randomization used a predetermined computer-generated random sequence within each stratified group to ensure an equal number of adaptive and standard participants among those who chose varenicline and those who chose nicotine patches. Participants and staff were blinded to group allocation. During study operations, only the research pharmacy staff was aware of group allocation, and they dispensed placebos with visually identical packaging for both medications.