Safety of nicotine replacement therapy in critically ill smokers: a retrospective cohort study
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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.
This retrospective cohort study was conducted in a 30-bed, university affiliated, teaching hospital ICU.
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.
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.