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During the congress, E-Posters will be accessible to all participants on the congress website 24/7, as well as in the E-poster stations in the congress center.
Preparing your E-Poster
Please review the E-Poster format requirements carefully when preparing your E-Poster. Should your E-Poster not meet the mentioned requirements, it may not be displayed as described above.
E-Poster Submission Deadline
Please prepare and upload your E-Poster no later than March 14, 2026 11.59PM CET. After this date, you will no longer be able to prepare and upload your E-poster and it will not be displayed and accessible on the congress website.
Please follow the instructions below to input your abstract title.
Abstract titles should be brief and reflect the content of the abstract.
Smoking is a significant risk factor for increased mortality in kidney transplant recipients (KTR). While KDIGO guidelines recommend annual tobacco use screening for KTR, self-reported smoking status is often unreliable, and urinary cotinine testing, considered the gold standard, is costly. Carboxyhemoglobin (COHb) has emerged as a reliable and cost-effective biomarker for identifying active smokers in KTR, with a cutoff value of 1.5% to classify active smoking. This study aims to explore the association between COHb levels, smoking exposure, and mortality in this population.
Plasma COHb was obtained from venous blood samples and measured using hemoxymetry as part of blood gas analysis. Smoking status was assessed through a questionnaire. Cox regression analyses were conducted to evaluate the association between COHb levels and mortality.
Among 1328 KTR (mean age 57 ± 14 years, 49% female, median time post-transplant 12 [IQR 12-85] months), the median COHb level was 0.93% [IQR 0.83-1.23%]. The prevalence of active smokers and history of delayed graft function occurring directly after transplantation were higher following the increasing COHb level (p < 0.001 and p=0.025, respectively). Triglyceride, C-reactive protein, and urinary albumin excretion were significantly higher according to increasing COHb level (p < 0.001, p < 0.001, and p = 0.026, respectively). Estimated glomerular filtration rate was not associated with COHb levels. During a median follow-up of 4 years, 189 (14.2%) patients died. Higher COHb levels were independently associated with higher mortality risk (hazard ratio [95% Confidence Interval (CI)] per standard deviation increase = 1.23 [1.11-1.37], p < 0.001). This association remained independent of adjustment for potential confounders, even including smoking status assessed by questionnaire (HR= 1.34 [95% CI 1.19-1.51], p < 0.001, model 4, Table 1). Kaplan-Meier curve analysis showed that patients survival probability was significantly lower among individuals with higher COHb levels (Figure 1).
COHb, which previously recognized as a reliable biomarker for detecting active smokers and more accessible than urinary cotinine, was found to be independently associated with an increased risk of mortality in KTR. Regular evaluation of COHb levels in clinical practice can improve physicians' awareness of patients' smoking status, enabling timely interventions to reduce mortality risk. This abstract was previously submitted and published in the 62nd European Renal Association (ERA) Congress abstract book (doi.org/10.1093/ndt/gfaf116.0859).
