Nicotine dependence among critically ill COVID-19 patients: A population-based cohort study.

Nicotine dependence is associated with lower life expectancy and patients who use nicotine are at an increased risk of diseases of the respiratory system. Data on the prognostic impact of nicotine dependence in COVID-19 is inconclusive. We used publicly available, statewide, and deidentified records to study hospitalizations of patients aged ≥ 18 years with a principal diagnosis of COVID-19 admitted to the intensive care units of acute care hospitals in Texas from Q2 2020 through Q4 2024. We measured the effect of nicotine dependence on mortality in the overlap population using weighted multivariable logistic regression and g-computation. We identified 142,045 hospitalizations admitted to intensive care units with a principal diagnosis of COVID-19 of which 10,452 (7.3%) were classified as currently nicotine dependent, 23,671 (16.7%) as formerly nicotine dependent, and 107,922 (76.0%) as never nicotine dependent. Currently and formerly nicotine dependent individuals had significantly higher burden of comorbidities compared to never nicotine dependent individuals; mean [standard deviation] Deyo comorbidity index 1.8 [1.9] and 1.8 [1.9] vs 1.4 [1.8] but lower rates of in-hospital mortality 10.7% and 13.8% vs 16.1%. On adjusted analysis, current nicotine dependence and former nicotine dependence remained associated with reduced in-hospital and short-term mortality. Additional investigations exploring the mechanisms leading to these findings are necessary.