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. 2024 Jan 3:67:102401.
doi: 10.1016/j.eclinm.2023.102401. eCollection 2024 Jan.

Carbon monoxide and prognosis in smokers hospitalised with acute cardiac events: a multicentre, prospective cohort study

Jean-Guillaume Dillinger  1 , Théo Pezel  1 , Clément Delmas  2 , Guillaume Schurtz  3 , Antonin Trimaille  4 , Nicolas Piliero  5 , Claire Bouleti  6 , Benoit Lattuca  7 , Stéphane Andrieu  8 , Julien Fabre  9 , Reza Rossanaly Vasram  10 , Jean-Claude Dib  11 , Victor Aboyans  12 , Charles Fauvel  13 , Francois Roubille  14 , Edouard Gerbaud  15   16 , Albert Boccara  17 , Etienne Puymirat  18 , Solenn Toupin  1 , Eric Vicaut  19 , Patrick Henry  1 ; ADDICT-ICCU trial
Collaborators, Affiliations

Carbon monoxide and prognosis in smokers hospitalised with acute cardiac events: a multicentre, prospective cohort study

Jean-Guillaume Dillinger et al. EClinicalMedicine. .

Abstract

Background: Smoking cigarettes produces carbon monoxide (CO), which can reduce the oxygen-carrying capacity of the blood. We aimed to determine whether elevated expiratory CO levels would be associated with a worse prognosis in smokers presenting with acute cardiac events.

Methods: From 7 to 22 April 2021, expiratory CO levels were measured in a prospective registry including all consecutive patients admitted for acute cardiac event in 39 centres throughout France. The primary outcome was 1-year all-cause death. Initial in-hospital major adverse cardiac events (MAE; death, resuscitated cardiac arrest and cardiogenic shock) were also analysed. The study was registered at ClinicalTrials.gov (NCT05063097).

Findings: Among 1379 patients (63 ± 15 years, 70% men), 368 (27%) were active smokers. Expiratory CO levels were significantly raised in active smokers compared to non-smokers. A CO level >11 parts per million (ppm) found in 94 (25.5%) smokers was associated with a significant increase in death (14.9% for CO > 11 ppm vs. 2.9% for CO ≤ 11 ppm; p < 0.001). Similar results were found after adjustment for comorbidities (hazard ratio [HR] [95% confidence interval (CI)]): 5.92 [2.43-14.38]) or parameters of in-hospital severity (HR 6.09, 95% CI [2.51-14.80]) and propensity score matching (HR 7.46, 95% CI [1.70-32.8]). CO > 11 ppm was associated with a significant increase in MAE in smokers during initial hospitalisation after adjustment for comorbidities (odds ratio [OR] 15.75, 95% CI [5.56-44.60]) or parameters of in-hospital severity (OR 10.67, 95% CI [4.06-28.04]). In the overall population, CO > 11 ppm but not smoking was associated with an increased rate of all-cause death (HR 4.03, 95% CI [2.33-6.98] and 1.66 [0.96-2.85] respectively).

Interpretation: Elevated CO level is independently associated with a 6-fold increase in 1-year death and 10-fold in-hospital MAE in smokers hospitalized for acute cardiac events.

Funding: Grant from Fondation Coeur & Recherche.

Keywords: Acute cardiac events; Carbon monoxide; Cardiovascular events; Death; Smoking; Tobacco.

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Conflict of interest statement

Jean-Guillaume Dillinger, Théo Pezel, Clément Delmas, Guillaume Schurtz, Antonin Trimaille, Nicolas Piliero, Claire Bouleti, Benoit Lattuca, Stéphane Andrieu, Julien Fabre, Reza Rossanaly Vasram, Jean-Claude Dib, Charles Fauvel, Albert Boccara, Etienne Puymirat, Solenn Toupin, Eric Vicaut and Patrick Henry report no conflict of interests. Victor Aboyans reports consulting fees from Astra-Zeneca, honoria for lectures or presentations from Boehringer, Bayer and Novonordisk, participation on a DSMB for Bayer, member of a committee of the European Society of Cardiology and of the French Society of Cardiology. Francois Roubille reports honoria for lectures or presentations from Astra Zeneca, Boehringer, Astra Zeneca, Vifor, Bayer, Pfizer, Novartis, Servier, Novo-Nordisk, Air liquid, Abbott, QuidelOrtho, GSK. Edouard Gerbaud reports consulting fees from Terumo Corporation, Abbott vascular and honoria for lectures from Servier. Authors had full access to all the data in the study and, accept responsibility to submit for publication.

Figures

Fig. 1
Fig. 1
Distribution of CO levels by smoking status. Concentration of expiratory CO levels in the population according to smoking status. Data are presented as box and, whisker plot. Abbreviations: CO: carbon monoxide; ppm: parts per million.
Fig. 2
Fig. 2
Kaplan Meier curves of all-cause death in active smokers according to CO level cut off. Data are presented according to CO levels: CO level >11 ppm (red line) vs. CO level ≤11 ppm (blue line). Abbreviations: CO: carbon monoxide; ppm: parts per million; HR: Hazard ratio; CI: confidence interval.
Fig. 3
Fig. 3
Rate of in-hospital MAE in active smokers according to CO level. First bar is smokers with CO level ≤11 ppm (threshold found–n = 260). The other bars are quartiles of the population of smokers with CO > 11 ppm: 12–13 ppm; 14–16 ppm; 17–19 ppm; 20–50 ppm. Abbreviations: CO: Carbon monoxide; MAE: in-hospital major adverse event.
Fig. 4
Fig. 4
Kaplan Meier curve of all-cause death in the overall population according to CO level cut off and, smoking status. Panel A: CO level >11 ppm vs. CO level ≤11 ppm. Panel B: Active smokers vs. non or former smokers. Abbreviations: CO: carbon monoxide; ppm: parts per million; HR: Hazard ratio; CI: confidence interval.
See this image and copyright information in PMC

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