Prevalence, Clinical Reasons and Associated Factors of Extended Treatment Duration for Drug Susceptible Tuberculosis – a Real-World Experience

Abstract Purpose The standard short-course treatment for drug-susceptible tuberculosis (TB) is 6 months, but in certain cases, treatment duration may need to be extended. However, limited research has been conducted on the prevalence and factors associated with extended TB treatment. Methods A retrospective study was conducted. Drug-susceptible patients with TB from the TB registry of a study hospital between January 2018 and December 2020 were enrolled. The prevalence, reasons, and associated factors for extended TB treatment (≥ 9 months) were analyzed and compared with those of the standard treatment course. Results A total of 221 patients with TB were analyzed, of whom 80 (28.7%) received extended TB treatment and 141 were in the control group. The extended treatment group had higher proportions of hepatitis B infection (12.5% vs. 5%, p = 0.043) and recent treatment for cancer (17.5% vs. 8.5%, p = 0.046). Adverse drug events were more prevalent in the extended treatment group (grade 3 or more symptoms: 26.3% vs. 11.3%, p = 0.008), and treatment interruption was more frequent (46.3% vs. 18.4%, p < 0.001). Logistic regression analysis revealed that hepatitis B infection (adjusted odds ratio [AOR] 3.10, p = 0.039), recent treatment for cancer (AOR 3.09, p = 0.013), and post-treatment abnormal aminotransferase (AOR 2.40, p = 0.014) were independent factors associated with extended treatment duration. Conclusions Extended anti-TB treatment is not uncommon, affecting 28.7% of the patients in this study. Factors such as host characteristics and adverse drug effects might contribute to extended TB treatment duration. Integration of these factors into treatment strategies is necessary to optimize patient care.