Table 1

 Nicotine replacement therapy (NRT) trials with final end points more than one year after treatment

StudyTime of final follow-upNRT product*DoseControl condition†Maximum period of NRT useAbstinence criterion‡Biochemical verification§
*Gum, nicotine chewing gum; NNS, nicotine nasal spray; Patch, nicotine transdermal patch.
†In addition to placebo, control group received the same counselling and support as NRT group. This varied in type and intensity across studies.
‡Continuous  =  no smoking after start of outcome observation period. Sustained  =  continuous abstinence but allowing some very limited smoking lapses throughout the follow-up period. PP (point prevalence)  =  abstinence from smoking in the week before follow up.
§CO, expired-air carbon monoxide; Cot, saliva cotinine.
¶CO verification not conducted in all clinical centres in study.
Blondal 19892 yearsGum4 mgPlacebo12 weeksContinuousNone
Blondal 19972 yearsNNS0.5 mgPlacebo52 weeksContinuousCO <10 ppm
Blondal 19996 yearsNNS0.5 mgPlacebo52 weeksSustainedCO <10 ppm
Clavel 19974 yearsGum2 mgPlacebo26 weeksSustainedCO <10 ppm
Daughton 19994.6 yearsPatch21 mg/24 hPlacebo12 weeksSustainedCO <10 ppm¶
Glavas 20035 yearsPatch21 mg/24 hPlacebo3 weeksPPCO <10 ppm
Herrera 19952 yearsGum2 mgPlacebo12 weeksSustainedCO <10 ppm
Mikkelsen 19943 yearsPatch15 mg/16 hPlacebo16 weeksSustainedCO <10 ppm
Richmond 19973 yearsPatch21 mg/24 hPlacebo10 weeksContinuousCO <10 ppm
Stapleton 19983.3 yearsNNS0.5 mgPlacebo52 weeksSustainedCO <10 ppm
Tonnesen 19882 yearsGum2 mgPlacebo16 weeksContinuousCO<10ppm
Yudkin 20038 yearsPatch21 mg/24 hPlacebo12 weeksContinuousCot <15 ng/ml