Measuring cigarette dependence: A comparison of two scales in two different groups of smokers

INTRODUCTION: The Fagerström Test for Cigarette Dependence (FTCD) and the Cigarette Dependence Scale (CDS) are usually used to assess cigarette dependence in clinical- and population-based studies. Our objective was to compare these two scales within groups of smokers from both contexts. METHODS: The study was observational with smokers from a representative sample of the adult general population (n=188) and smokers attending a smoking cessation clinic in Barcelona, Spain (n=759). The FTCD and the CDS-5 (short version of 5 items) were used to assess cigarette dependence. We compared the standardized median scores obtained with both scales within each group of smokers by selected variables. To this aim, we re-scaled the scores of both scales to allow their comparison and assess their correlation within both groups. RESULTS: The scores obtained with both scales were highly correlated within both groups of smokers (p<0.001), indicating good agreement in the assessment of cigarette dependence. Nevertheless, higher standardized CDS-5 scores were observed more frequently in the population group overall (3.9 vs FTCD score=3.7, p=0.001), among women (4.5 vs 4.2; p<0.001), in the youngest group of smokers (3.9 vs 3.2; p<0.007) and in light smokers (time to the first cigarette >60 min; 1.7 vs 1.1; p<0.001). CONCLUSIONS: While the CDS-5 scored higher more frequently in the population group, the FTCD scored higher more frequently in the clinical group. These differences should be considered when designing either clinical- or population-based studies.