title: Safety of nicotine replacement therapy in critically ill smokers: a retrospective cohort study.
abstract: OBJECTIVE
  Nicotine replacement therapy (NRT) has been used to ameliorate nicotine withdrawal in the intensive care unit (ICU). Previous cohort studies have suggested an increased mortality with NRT use: methodological problems may call into question the validity of these findings. We undertook a retrospective cohort study to determine if NRT use was associated with adverse outcomes.
  
  
  METHODS
  This retrospective cohort study was conducted in a 30-bed, university affiliated, teaching hospital ICU.
  
  
  RESULTS
  We identified 423 smokers admitted over 2 years, of whom 73 received transdermal NRT. Cox proportional hazard regression models, with NRT modelled as a time-varying covariate, were used to test the hypothesis that NRT was associated with an altered ICU or hospital mortality. A second analysis utilized propensity scores. The unadjusted ICU and hospital mortalities were lower for the NRT group; although both differences were non-significant. The Cox models showed that, after adjustment for APACHE risk, age, sex and alcohol use, risk associated with NRT administration was not statistically different than non-administration for both ICU (hazard ratio 0.50, [95 % CI 0.20-1.24], p = 0.14) and hospital (hazard ratio 0.95, [95 % CI 0.52-1.75], p = 0.88) mortality. Similar findings occurred with the propensity matched analysis.
  
  
  CONCLUSIONS
  We were unable to demonstrate any harm associated with NRT, with the ICU model actually trending towards benefit. We conclude that a randomised, blinded, placebo controlled trial is required to assess adequately the safety and efficacy of NRT as a treatment in critically ill smokers.
authors.affiliation: Department of Critical Care, First Floor East Wing, Guy's and St Thomas' NHS Foundation Trust, Westminster Bridge Road, London SE1 9EH, UK. michael.gillies@nhs.net
authors.forename: Michael A
authors.initials: MA
authors.lastname: Gillies
authors.forename: C A
authors.initials: CA
authors.lastname: McKenzie
authors.forename: C
authors.initials: C
authors.lastname: Whiteley
authors.forename: R J
authors.initials: RJ
authors.lastname: Beale
authors.forename: S M
authors.initials: SM
authors.lastname: Tibby
mesh_terms: D018806:APACHE; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D016638:Critical Illness; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012907:Smoking / Q000628:therapy*; D016540:Smoking Cessation / Q000379:methods*; D013375:Substance Withdrawal Syndrome / Q000188:drug therapy*; D061485:Tobacco Use Cessation Devices / Q000009:adverse effects*; D055815:Young Adult