Use of cotinine urinalysis to verify self-reported tobacco use among male psychiatric out-patients

CONTEXT: There is a complex and significant correlation between respiratory disorders and psychiatric conditions. Reliability of self-reported tobacco use has been questioned in recent times. AIMS: The current study aims at assessment of accuracy of self-reported tobacco use (both smoked and smokeless) among psychiatric out-patients. SETTINGS AND DESIGN: We recruited 131 consecutive subjects from the out-patient psychiatry department of a tertiary care hospital. MATERIALS AND METHODS: Male patients meeting the study criteria were approached for participation in the study. They were asked about their recent tobacco use history. Those reporting recent use were assessed for severity of dependence using Fagerstrom Test for Nicotine Dependence (FTND)-smoking and FTND-smokeless scales. Quantitative urine cotinine analysis was performed using the Enzyme Linked Immunesorbant Assay (ELISA) method. Based on this method, a (50 ng/ml) cut off score for urinary cotinine level for tobacco use was set. STATISTICAL ANALYSIS USED: Concordance between the self-report of tobacco use and urinary cotinine level was assessed using the Cohen's kappa. Additionally, Pearson's correlation coefficient was used to examine the correlation between the FTND-smoking and FTND-smokeless scales and the urinary cotinine levels. RESULTS: The values of Cohen's kappa suggest no significant concordance between the self-reported recent tobacco use and urinary cotinine levels for both smoking and smokeless tobacco forms. The discordance was present irrespective of a higher (550 ng/ml) or a lower (50 ng/ml) cut off score for a urinary cotinine level. Pearson's correlation coefficient failed to reveal any significant direct correlation between the FTND scores and urinary cotinine levels. CONCLUSIONS: It is recommended to use biological markers such as urinary cotinine levels to corroborates the information provided by the patients.