Does smoking affect treatment outcomes of newly-diagnosed pulmonary tuberculosis patients?

Introduction: Despite the decreasing prevalence of tuberculosis (TB) in some developed countries, this disease is still considered as a worldwide public health issue. Along with smoking as one of its important risk factors, these two epidemics impose a great burden particularly in developing countries. Tobacco use have been reported to be correlated with different aspects of TB disease but its cessation effects on sputum smear conversion is still a matter of discussion.Method: All the smear posetive newly-diagnosed TB patients referring to health centers and Masih Daneshvari hospital in Tehran during December ۲۰۱۲ to February ۲۰۱۴ were assessed and the eligible subjects were included in this clinical trial. Smokers patients participated in smoking cessation programs. Sputum smear test was performed at the end of ۲.۵ and ۶ month of treatment and smoking status of the subjects was evaluated at the end of the six months. Regarding their smoking status, subjects were categorized into three groups of nonsmokers, smokers and quitters and the differences in smear conversion rates were evaluated between the three groups.Results: A total of ۱۸۳ smoker subjects and ۱۵۱ nonsmokers were included and followed through ۶ months of treatment. Cure rate at the end of six months was found to be significantly higher among nonsmoker patients compared to quitters and smokers (۸۳.۴%, ۸۰.۸% and ۶۷.۶%, respectively) (P-Value<۰.۰۰۱). Smear conversion rates were found to be highest among nonsmokers, and higher among quitters compared to smokers. GEE modeling showed that smoking increased the chance of remaining positive sputum smear (P-Value<۰.۰۰۱, OR=۳.۵۱, ۹۵%CI=۱.۹۵-۶.۳۰). No significant difference was found between smoker patients and those who managed to quit. Increasing age (P-Value<۰.۰۰۱, OR=۱.۰۳, ۹۵%CI=۱.۰۲-۱.۰۵) and living in urban areas (P-Value<۰.۰۰۱, OR=۱.۶۲, ۹۵%CI=۱.۰۱-۲.۶۲) were also found to increase the chance of a positive smear test.Conclusions: Smoking cessation was found to increase smear conversion rates and decrease treatment failure rates and is recommended to be included as an important part of TB control plans.

Keywords:

Tuberculosis , Smoking , Cessation , Sputum smear , Conversion