Evaluating the effectiveness of nicotine replacement therapy in critically ill smokers: A meta-analysis of randomized controlled trials

Introduction The effectiveness of nicotine replacement therapy (NRT) in critically ill patients remains uncertain, as conflicting research results have been reported. Despite potential side effects and inconsistent data on safety and efficacy, NRT is still prescribed in intensive care units (ICUs) to prevent withdrawal symptoms and manage agitation in patients who are smokers. This meta-analysis aimed to assess the effectiveness of nicotine replacement therapy in critically ill smoking patients. Methods A systematic review and meta-analysis of randomized controlled trials investigated the outcomes of smokers admitted to ICUs and were randomized either to receive or not receive nicotine replacement therapy (NRT) during their ICU stay. The MEDLINE and Embase databases were searched from inception through 13 February 2023 using OVID. The primary outcome was ICU length of stay (LOS) for this systematic review and meta-analysis. Meta-analysis was conducted using both random-effects and fixed-effect models; the latter is recommended when meta-analysis is restricted to just a few studies. The study was registered in the Prospective International Register of Systematic Reviews (PROSPERO) under reference number CRD42023407804. Results Of 28 studies initially identified, three, with 67 patients on NRT and 72 controls, were deemed eligible for pooled analysis. Patients who received NRT experienced a shorter LOS (mean difference, MD= -3.06; 95% CI: -5.88 – -0.25, p=0.0, I 2 =0%). The mechanical ventilation (MV) duration was also shorter in the NRT group, but this difference was not statistically significant (MD= -1.24; 95% CI: -3.21–0.72, p=0.22, I 2 =12.69%). Delirium duration was reported by two studies, from which pooled analysis revealed an MD of -0.50 (95% CI: -1.63–0.62, I 2 =0%). The vasopressor duration was assessed in two studies, and the overall MD for vasopressor duration was not statistically different between NRT patients and controls in the fixed-effects model (MD=0.11; 95% CI: -0.75–0.96, I 2 =0%). Conclusions Critically ill smoker patients who received NRT experienced a significantly shorter ICU LOS but no significant differences in the durations of MV, vasopressor use, or delirium.