Assessment of serum cotinine in patients with chronic heart failure: self-reported versus objective smoking behaviour.

BACKGROUND: Smoking is a major risk factor in the development of coronary artery disease and thus chronic heart failure (HF). The value of self-reported smoking behaviour has not been validated in patients with HF. We sought to assess serum cotinine levels, a marker of recent tobacco exposure, in a cohort of clinically stable patients with chronic HF.

METHODS AND RESULTS: We analysed serum cotinine values in 75 patients with chronic HF [mean age ± SD 64 ± 16 years, 85 % male, left ventricular ejection fraction 30 ± 1 %, New York Heart Association class (I/II vs. III/IV) 73 %/27 %, haemoglobin (Hb) 13.4 ± 1.5 g/dL, serum creatinine 1.21 ± 0.51 mg/dL] and 30 control subjects of similar age (63 ± 11 years, 43 % male, Hb 14.1 ± 1.5 g/dL, creatinine 1.12 ± 0.92 mg/dL) using a chemiluminescence immunoassay. Patients were interviewed about their smoking habits, and routine laboratory parameters were analysed. In patients with HF, cotinine values ranged from undetectable to 829 μg/L (mean 110 ± 208 μg/L). Similar findings were evident in healthy subjects with cotinine ranging from undetectable to 860 μg/L (mean 105 ± 208 μg/L). Serum cotinine levels correlated with leukocyte count and haemoglobin concentration (both p < 0.05). Self-reported smoking behaviour did not correspond to serum cotinine level in serum in 16.9 % of the patients with chronic HF. No such finding was evident in control subjects.

CONCLUSIONS: Serum cotinine measurement provides an easily applicable means to analyse smoking behaviour in patients with chronic HF. Its assessment may permit analysis of smoking deception in daily clinical routine.