Agreement between the Fagerström test for nicotine dependence (FTND) and the heaviness of smoking index (HSI) for assessing the intensity of nicotine dependence among daily smokers.

Introduction: Measuring the level of nicotine addiction among smokers is an integral part of enhancing smoking cessation as nicotine dependence is one of the barriers to smoking cessation. In this study, we compared the level of agreement between FTND and HSI in detecting high nicotine dependence among daily smokers.

Methods: We collected data from participants of a public smoking cessation clinic in Selangor. A trained pharmacist conducted face-to-face interviews with 152 daily smokers using a structured validated questionnaire. Respondents were classified as having high nicotine dependence using both the HSI (score ≥4) and the FTND (score ≥6), and concordance between the two measures, kappa statistics and sensitivity, specificity of the HSI were then determined with the FTND classification as the reference standard.

Results: The HSI had a substantial agreement with the FTND (Cohen's kappa=0.72) in measuring high levels of nicotine addiction, with good sensitivity (83.3%) and specificity (89.4%).

Conclusions: The findings suggest that the HSI can be used instead of the FTND in clinical-based investigations to screen for high nicotine dependence among daily smokers in the clinical setting.