Characteristics and Determinants of Treatment Default Among Smokers With Tuberculosis in an Industrial State of Malaysia: A Registry-based Study of the Years 2013-2017

Abstract

Background: The increased risk of treatment default among smokers raises concern over the secondary spread within the community. This study aimed to determine the prevalence and factors associated with treatment default among TB patients who smoke.Methods: A retrospective cohort of all registered TB patients who smoke in the state of Selangor between 2013 and 2017 via the Malaysian National MyTB database was included for analysis. TB patients who smoke were considered those with an active smoking status during the notification, while treatment default was defined as a TB patient who had interrupted treatment for 2 months or longer. There were 4 main variable domains included for analysis: sociodemographic profiles, disease profiles, treatment profiles, and comorbidities. Logistic regression analysis was used to identify determinants of treatment default among TB patients who smoke.Results: A total of 27.6% (N=6278) of the TB patients registered in Selangor were active smokers, and 15.1% (N=813) of the TB patients who smoke experienced defaulted TB treatment. The determinants of treatment default among TB patients who smoke were patients staying in an urban area (AOR 1.47; 95% CI 1.11,1.96), median income level less than RM2160 (AOR 2.0; 95% CI 1.34,2.99), no formal education (AOR 2.12; 95% CI 1.31,3.44), previously treated cases (AOR 2.78; 95% CI 1.99,3.88), active TB case detection methods (AOR 2.05; 95% CI 1.21,3.47), treatment duration of less than 6 months (AOR 7.56; 95% CI 5.74,9.92), and patients not on DOTS during the continuation phase (AOR 27.96; 95% CI 21.1,37.1). All the significant factors gave rise to the final model of determinants, with a predictability of 92.9% (95% CI 92.0,93.7).Conclusions: Our findings highlighted the high prevalence of treatment default among TB patients who smoke compared to the general TB population. Early risk detection that examines the two main domains of risk factors (socioeconomic factors and treatment profiles) should be provided for those who smoke in the TB population. Interventions should aim to reduce the prevalence of smoking among TB patients, together with close supervision during DOTS.