Non-standard anti-tuberculosis regimens at the initial prescription

A retrospective observational study sought to evaluate the real-world use and clinical implications of non-standard initial tuberculosis (TB) treatment among patients diagnosed with drug-susceptible pulmonary TB. Specifically, the researchers aimed to determine how often non-standard regimens were prescribed, identify the risk factors influencing this treatment decision, and examine the resulting impact on clinical outcomes. The study population included patients aged 20 years or older who received anti-TB medications between January 2010 and December 2020 at a single hospital. Patients were categorized into two groups: those who received the standard intensive-phase regimen and those who did not, with the latter group referred to as the NSTB (non-standard TB) group.

To create a reliable comparison, patients in the NSTB group were matched 1:1 with patients in the STB (standard TB) group based on age, sex, and treatment year. The researchers found that non-standard regimens were relatively uncommon, prescribed in only 3.7% of cases. However, the analysis revealed specific pre-existing health conditions that significantly increased the likelihood of receiving a non-standard regimen. Liver disease emerged as the strongest predictor, with an adjusted odds ratio (aOR) of 12.79. Eye disease and gout or hyperuricemia were also significant independent risk factors, with aORs of 8.87 and 4.01, respectively.

Patients receiving non-standard regimens experienced less favorable treatment outcomes. The NSTB group had a significantly longer average treatment duration (281 days compared to 223 days) and a higher rate of treatment interruption (26% versus 8%). Additionally, the rate of loss to follow-up was notably higher in this group. These clinical challenges may be attributed in part to the omission of key drugs in the initial treatment regimens. The most frequently excluded medications in the NSTB group were pyrazinamide (60%) and ethambutol (34%), both of which are cornerstone components of standard TB therapy.

The findings highlight an important clinical dilemma: while non-standard regimens are sometimes necessary due to comorbidities that increase the risk of adverse drug reactions, they are linked with poorer treatment adherence and extended therapy durations. This raises concerns about the long-term effectiveness and management of TB in patients with complex health profiles.

In conclusion, this study underscores the need for tailored TB treatment strategies for patients with contraindications to standard medications. Identifying individuals at risk for non-standard regimen use allows for proactive care planning. Moreover, developing and validating alternative treatment options may help minimize adverse outcomes and improve overall TB control in these vulnerable patient populations.

Source: Chen, R.T., Liu, C.Y., Lin, S.Y., Shu, C.C. and Sheng, W.H., 2024. The prevalence, clinical reasoning and impact of non-standard anti-tuberculosis regimens at the initial prescription. Scientific Reports, 14(1), p.5631.