Tobacco use disorder: Prevalence, associated factors and its influence on quality of life among patients on methadone assisted treatment.

Background and Objectives: Smoking is the primary cause of preventable death and is highly prevalent among patients on methadone assisted treatment (MAT). This study aims to assess the prevalence of tobacco use disorder (TUD) among patients on MAT, the factors associated with TUD, and to examine the association between TUD and quality of life.Methods: A total of 171 male patients receiving MAT in two Malaysian government hospitals were assessed for TUD, levels of nicotine dependence, relevant associated factors and quality of life using DSM-5 criteria, Fagerström Test for Nicotine Dependence (FTND), Opiate Treatment Index (OTI), Mini-International Neuropsychiatric Interview (M.I.N.I.) and World Health Organization Quality of Life (WHOQOL)-BREF.Results: The prevalence of TUD was 81.3%. Being employed was significantly associated with having a TUD. Among the patients with TUD, the mean FTND score was 3.8 (SD ± 2.0). Being younger, having poorer social function, and presence of current opioid dependence were significantly correlated with higher FTND scores. There was no significant difference in the quality of life between patients with and without TUD. Following multiple linear regression analysis, being unmarried and poor health status were the two factors that significantly predicted a lower quality of life in all four domains of WHOQOL-BREF.Conclusions: Given the high prevalence of TUD among methadone-assisted patients, smoking cessation treatment should be integrated into the MAT program in Malaysia. Also, addressing patients' marital and health issues during MAT can be instrumental in improving their quality of life.