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Table 1 Study population selection process

From: General practitioner prescribing of single and combination nicotine replacement therapy in the UK: a retrospective database study

Selection process n %
Inclusion: people with an NRT product during the study period 128,115 100.00
Exclusion: people with NRT non-patch products only during the study period 31,129 24.30
NRT non-patch products (N = 31,129):   
 NRT gum only 5,228 16.79
 NRT tablet only 1,187 3.81
 NRT inhalator only 15,750 50.60
 NRT lozenge only 3,631 11.66
 NRT oral spray only 589 1.89
 NRT nasal spray only 527 1.69
 More than one type of NRT non-patch 4,217 13.55
People with NRT patch product during the study period 96,986 75.70
Exclusions (N = 96,986) a   
 Under 18 years old 3,197 3.30
 Less than six months of baseline data 15,316 15.79
 Less than fourteen days of follow-up data 193 0.20
 History of NRT products (patch or non-patch)b 39,068 40.28
 History of bupropion or varenicline 13,789 14.22
Study population 38,954 30.41
  1. aBased on date of first NRT patch during the study period. Patients were not excluded in a cascade manner, therefore some patients met more than one of the exclusion criteria. A total of 58,032 patients with an NRT patch product were excluded.
  2. bHistory of NRT patch product any time prior to index date (date of first patch during study period) or history of NRT non-patch product any time before two weeks prior to index date.