Poor treatment outcome and associated risk factors among patients with isoniazid mono-resistant tuberculosis: A systematic review and meta-analysis

Treatment outcomes and key factors contributing to unfavourable outcomes among isoniazid-resistant pulmonary tuberculosis patients in Shanghai, China

OBJECTIVE

Given that more than 1 million people annually develop isoniazid-resistant tuberculosis (Hr-TB), the issue of Hr-TB may go unnoticed. However, limited studies have focused on the clinical treatment of Hr-TB in China, particularly regarding treatment outcomes and influencing factors. This study aimed to evaluate the treatment outcomes of Hr-TB patients in Shanghai from 2018 to 2021 and analyse the influencing factors, including demographic characteristics, clinical features, and treatment-related factors.

METHODS

This study retrospectively reviewed the medical records of Hr-TB patients registered in the TB management information system from 2018 to 2021. Differences in demographic characteristics, clinical information, and treatment outcomes were evaluated. Multivariable logistic regression was used to identify risk factors associated with unfavourable outcomes.

RESULTS

A total of 664 patients with Hr-TB were included in the analysis. A total of 84 cases (12.7%) had unfavourable outcomes. Only 318 (47.9%) Hr-TB patients used regimens containing fluoroquinolones. Adverse events occurred in 127 cases (19.1%), of which 12 cases (1.81%) discontinued treatment due to adverse events. There was statistically significant difference in the occurrence of adverse events between the different treatment regimens (P < 0.001). Multivariable logistic regression showed that older age (adjusted odds ratio = 6.13, 95% confidence intervals [CI] = 1.24-30.24, P = 0.026), use of injectable agents (adjusted odds ratio = 3.75, 95% CI = 1.29-10.94, P = 0.016), and treatment duration (95% CI = 21.85-1487.61, P < 0.001) were risk factors for unfavourable treatment outcomes.

CONCLUSIONS

Unfavourable outcomes were more frequent among older patients and those receiving injectable agents among Hr-TB patients in Shanghai, a low-endemic region for TB. This emphasizes the need for timely diagnosis and optimized treatment strategies for isoniazid-resistant tuberculosis.

Impact of rpoB gene mutations and Rifampicin-resistance levels on treatment outcomes in Rifampicin-resistant tuberculosis

BACKGROUND

Although many studies have examined the connection between mutations in the rpoB gene and drug resistance, the impact of common mutations on treatment outcomes for RR-TB is not yet fully understood.

OBJECTIVES

This study explores the relationship between rpoB gene mutations and drug-resistant phenotypes, assesses their role in predicting RR-TB prognosis, and investigates the impact of disputed rpoB mutations in M. tuberculosis on treatment outcomes.

METHODS

192 rifampicin-resistant isolates were retested for drug susceptibility and gene sequencing. Minimum inhibitory concentrations (MICs) were determined for 98 isolates with disputed rpoB gene mutations. These mutations can cause low-level resistance to rifampicin, leading to inconsistencies in drug susceptibility testing and impacting medication therapy decisions.

RESULTS

Of 192 cases, 116 (60.4%) achieved successful outcomes, while 76 (39.6%) were unsuccessful. Among the 98 isolates tested for phenotypic drug susceptibility testing (DST) based on minimum inhibitory concentration (MIC), 67 (68.4%) showed high-level resistance with a MIC of ≥ 1 µg/mL. In contrast, 31 (31.6%) drug-susceptible tuberculosis isolates exhibited low-level resistance with a MIC of < 1.0 µg/mL. Of the 31 isolates with low-level resistance, 14 (45.2%) had successful treatment outcomes, while 17 (54.8%) did not. Among the 67 isolates with high-level resistance, 41 (61.2%) achieved successful outcomes, whereas 26 (38.8%) did not. In analysing the 14 codons of the Rifampicin Resistance Determining Region (RRDR) of the rpoB gene, the Leu430Pro codon showed the highest odds ratio (OR) of 2.98 (95% CI: 0.96-9.27) with a p-value of 0.0591, indicating statistically not significant. However, this suggests a potential association with rifampicin resistance that requires further investigation, particularly in areas with high drug-resistant tuberculosis prevalence. Other reported variants had lower odds ratios: Asp435Val with 1.23 (95% CI: 0.32-4.75), Asp435Tyr with 1.86 (95% CI: 0.60-5.76), His445Tyr with 1.16 (95% CI: 0.47-2.91), and Ser450Leu with 1.44 (95% CI: 0.81-2.58).

CONCLUSIONS

This study indicates that low-level rifampicin mono-resistance in tuberculosis (TB) patients is associated with poor clinical outcomes. A mutation at the Leu430Pro codon showed the highest odds ratio of 2.98 (p-value 0.0591), suggesting a potential association with rifampicin resistance that warrants further research, especially in areas with high drug-resistant TB. It highlights the need for more aggressive treatment strategies for patients with low-level rifampicin resistance, even if they seem solely mono-resistant.

Treatment outcomes among patients with isoniazid mono-resistant tuberculosis in Mumbai, India: A retrospective cohort study

Background

Tuberculosis (TB) remains a significant cause of mortality globally, with India accounting for 27% of the estimated number of people with TB. Multidrug-resistant TB (MDR-TB) and isoniazid (INH) resistance pose additional challenges to effective treatment. We aimed to describe treatment outcomes of INH mono-resistant TB patients under programmatic conditions in Mumbai, India.

Methods

This retrospective cohort study was conducted at Shatabdi Hospital in Mumbai between 2019-2021.We described the clinical and demographic characteristics, treatment outcomes, and risk factors for unfavourable outcomes among patients with INH mono-resistant TB treated with rifampicin, ethambutol, pyrazinamide, and levofloxacin (LfxREZ) for a duration of 6 months.

Results

Among 3105 patients with drug-resistant TB initiated on treatment, 217 (7 %) had INH mono-resistant TB. Of these, 54 % (117/217) were female, with a median age of 26 years (interquartile range: 20-40). The majority (88 %; 191/217) presented with pulmonary TB, and most (87 %; 188/217) had favourable treatment outcomes, including treatment completion (52 %; 112/217) and cure (35 %; 76/217). Unfavourable outcomes, including treatment failure (2.3 %; 5/217), loss to follow-up (9.2 %; 20/217), or death (1.8 %; 4/217), were observed in 13 % (29/217) of patients. A total of ten (5 %) patients experienced at least one non-severe adverse drug reaction. Factors associated with unfavourable outcomes included severe thinness (p = 0.019) and male gender (p = 0.012).

Conclusion

Treating INH mono-resistant patients with LfxREZ resulted in satisfactory outcomes and low toxicity. It is important to rule out drug resistance to INH while determining the treatment regimen.

Comparison of Nucleotide MALDI-TOF MS with Xpert MTB/RIF for Rifampicin Susceptibility Identification and Associated Risk Factors of Rifampicin Resistance Among Drug Resistant Mycobacterium tuberculosis

Purpose

Nucleotide-based matrix-assisted laser desorption ionization time-of-flight mass spectrometry (nucleotide MALDI-TOF MS) is an emerging molecular technology used for the diagnosis of tuberculosis (TB) caused by Mycobacterium tuberculosis (MTB)and its drug resistance. This study aimed to compare the ability of nucleotide MALDI-TOF MS to detect rifampicin (RIF) resistance in drug-resistant TB (DR-TB) patients with Xpert MTB/RIF and to analyze the disparate results individually. Additionally, potential factors associated with rifampicin resistance among DR-TB patients in Qingdao were investigated.

Patients and Methods

A retrospective study was conducted at Qingdao Chest Hospital, and patients with DR-TB were enrolled. Corresponding frozen isolates were recovered and subjected to nucleotide MALDI-TOF MS, Xpert MTB/RIF, and phenotypic drug susceptibility testing (pDST). Sanger sequencing was performed for the discordant results of nucleotide MALDI-TOF MS and Xpert MTB/RIF. Univariate and multivariate logistic regression analyses were used to identify potential factors associated with rifampicin resistance among patients with DR-TB.

Results

A total of 125 patients with DR-TB (18.8%, 125/668) were enrolled in this study from May 1 to July 31, 2023. Rifampicin-resistant (DR-TB/RR, 29) and rifampicin-sensitive (DR-TB/RS, 96) groups were divided according to the pDST results. Nucleotide MALDI-TOF MS performed better than Xpert MTB/RIF in terms of sensitivity, specificity, accuracy, and agreement with pDST. Only six cases had inconsistent results, and the sequencing results of five cases were identical to nucleotide MALDI-TOF MS. Furthermore, chest pain (aOR=12.84, 95% CI, 2.29-91.97, p=0.005), isoniazid sensitivity (aOR=0.14, 0.02-0.59, p=0.013), and ethambutol sensitivity (aOR=0.02, 0.00-0.10, p=0.000) were potential factors associated with rifampicin resistance among DR-TB patients in Qingdao.

Conclusion

The overall concordance between nucleotide MALDI-TOF MS and Xpert MTB/RIF was 95.2%, with the former performing better in determining rifampicin susceptibility among DR-TB cases in Qingdao. Chest pain, isoniazid, and ethambutol resistance might be factors associated with RIF resistance among patients with DR-TB in Qingdao.

Precision Medicine Strategies to Improve Isoniazid Therapy in Patients with Tuberculosis

Due to interindividual variability in drug metabolism and pharmacokinetics, traditional isoniazid fixed-dose regimens may lead to suboptimal or toxic isoniazid concentrations in the plasma of patients with tuberculosis, contributing to adverse drug reactions, therapeutic failure, or the development of drug resistance. Achieving precision therapy for isoniazid requires a multifaceted approach that could integrate various clinical and genomic factors to tailor the isoniazid dose to individual patient characteristics. This includes leveraging molecular diagnostics to perform the comprehensive profiling of host pharmacogenomics to determine how it affects isoniazid metabolism, such as its metabolism by N-acetyltransferase 2 (NAT2), and studying drug-resistant mutations in the Mycobacterium tuberculosis genome for enabling targeted therapy selection. Several other molecular signatures identified from the host pharmacogenomics as well as other omics-based approaches such as gut microbiome, epigenomic, proteomic, metabolomic, and lipidomic approaches have provided mechanistic explanations for isoniazid pharmacokinetic variability and/or adverse drug reactions and thereby may facilitate precision therapy of isoniazid, though further validations in larger and diverse populations with tuberculosis are required for clinical applications. Therapeutic drug monitoring and population pharmacokinetic approaches allow for the adjustment of isoniazid dosages based on patient-specific pharmacokinetic profiles, optimizing drug exposure while minimizing toxicity and the risk of resistance. Current evidence has shown that with the integration of the host pharmacogenomics-particularly NAT2 and Mycobacterium tuberculosis genomics data along with isoniazid pharmacokinetic concentrations in the blood and patient factors such as anthropometric measurements, comorbidities, and type and timing of food administered-precision therapy approaches in isoniazid therapy can be tailored to the specific characteristics of both the host and the pathogen for improving tuberculosis treatment outcomes.

Incidence, Outcomes, and Risk Factors for Isoniazid-Resistant Tuberculosis from 2012 to 2022 in Eastern China

BACKGROUND

Isoniazid-resistant, rifampicin-susceptible tuberculosis (Hr-TB) is the most frequent drug-resistant tuberculosis (DR-TB) in the world, and unfavorable outcomes of Hr-TB are more common compared to drug-susceptible TB. Considering there is no optimal regimen accepted worldwide, we undertook a retrospective cohort study in eastern China to estimate incidence trends and risk factors associated with unfavorable outcomes of Hr-TB.

METHODS

Between January 2012 and December 2022, all Hr-TB patients' information was extracted from the Tuberculosis Information Management System (TIMS), which is a national electronic information platform, to record TB patients' clinical information in this study. The incidence of Hr-TB was determined by the mid-year population according to census data published by the government. We categorized treatment regimens depending on fluoroquinolone (FQ) use, and potential risk factors were analyzed using multivariable logistic regression.

RESULTS

A total of 3116 Hr-TB patients fulfilled the inclusion criteria and were enrolled in this study. The average annual rate of Hr-TB in the 11 years under investigation was 0.34 per 100,000 and increased to 0.53 per 100,000 until 2019. In total, six different treatment regimens were utilized in the study sites, and less than 1% of regimens adopted FQ. There was no difference in the unfavorable outcomes between the FQ-included and FQ-excluded groups (p = 0.22). The average treatment duration was 7.06 months, and the longest treatment was 26 months. Approximately 20% (637/3116) of Hr-TB patients had unfavorable outcomes, and 60.13% (383/637) of them proceeded to multidrug-resistant tuberculosis (MDR-TB). Treatment duration and a positive smear at the end of the 5th month were significantly associated with unfavorable outcomes (p < 0.001).

CONCLUSION

The unfavorable treatment outcomes of Hr-TB are still high in eastern China, and the efficacy of FQ-containing regimens needs to be validated for Hr-TB treatment.

Spatial pattern of isoniazid-resistant tuberculosis and its associated factors among a population with migrants in China: a retrospective population-based study

Background

Isoniazid-resistant, rifampicin-susceptible tuberculosis (Hr-TB) globally exhibits a high prevalence and serves as a potential precursor to multidrug-resistant tuberculosis (MDR-TB). Recognizing the spatial distribution of Hr-TB and identifying associated factors can provide strategic entry points for interventions aimed at early detection of Hr-TB and prevention of its progression to MDR-TB. This study aims to analyze spatial patterns and identify socioeconomic, demographic, and healthcare factors associated with Hr-TB in Shanghai at the county level.

Method

We conducted a retrospective study utilizing data from TB patients with available Drug Susceptible Test (DST) results in Shanghai from 2010 to 2016. Spatial autocorrelation was explored using Global Moran's I and Getis-Ord G i ∗ statistics. A Bayesian hierarchical model with spatial effects was developed using the INLA package in R software to identify potential factors associated with Hr-TB at the county level.

Results

A total of 8,865 TB patients with DST were included in this analysis. Among 758 Hr-TB patients, 622 (82.06%) were new cases without any previous treatment history. The drug-resistant rate of Hr-TB among new TB cases in Shanghai stood at 7.20% (622/8014), while for previously treated cases, the rate was 15.98% (136/851). Hotspot areas of Hr-TB were predominantly situated in southwestern Shanghai. Factors positively associated with Hr-TB included the percentage of older adult individuals (RR = 3.93, 95% Crl:1.93-8.03), the percentage of internal migrants (RR = 1.35, 95% Crl:1.15-1.35), and the number of healthcare institutions per 100 population (RR = 1.17, 95% Crl:1.02-1.34).

Conclusion

We observed a spatial heterogeneity of Hr-TB in Shanghai, with hotspots in the Songjiang and Minhang districts. Based on the results of the models, the internal migrant population and older adult individuals in Shanghai may be contributing factors to the emergence of areas with high Hr-TB notification rates. Given these insights, we advocate for targeted interventions, especially in identified high-risk hotspots and high-risk areas.

The positivity rates and drug resistance patterns of Mycobacterium tuberculosis using nucleotide MALDI-TOF MS assay among suspected tuberculosis patients in Shandong, China: a multi-center prospective study

Objective

To investigate the positivity rates and drug resistance characteristics of Mycobacterium tuberculosis (MTB) among suspected tuberculosis (TB) patients in Shandong Province, the second-largest population province in China.

Methods

A prospective, multi-center study was conducted from April 2022 to June 2023. Pathogen and drug resistance were identified using nucleotide matrix-assisted laser desorption ionization time-of-flight mass spectrometry (nucleotide MALDI-TOF MS).

Results

Of 940 suspected TB patients included in this study, 552 cases were found to be infected with MTB giving an overall positivity rate of 58.72%. Total of 346 cases were resistant to arbitrary anti-TB drug (62.68%), with Zibo (76.47%), Liaocheng and Weihai (both 69.23%) ranking top three and TB treatment history might be a related factor. Monoresistance was the most common pattern (33.53%), with isoniazid the highest at 12.43%, followed by rifampicin at 9.54%. Further analysis of gene mutations conferring resistance revealed diverse types with high heteroresistance rate found in multiple anti-TB drugs.

Conclusion

A relatively high rate of MTB positivity and drug resistance was found in Shandong Province during and after the COVID-19 pandemic, indicating the need for strengthening rapid identification of species and drug resistance among suspected TB patients to guide better medication and minimize the occurrence of drug resistance.

How We Treat Drug-Susceptible Pulmonary Tuberculosis: A Practical Guide for Clinicians

Tuberculosis (TB) remains one of the leading causes of morbidity and mortality worldwide and pulmonary TB (PTB) is the main variant responsible for fueling transmission of the infection. Effective treatment of drug-susceptible (DS) TB is crucial to avoid the emergence of Mycobacterium tuberculosis-resistant strains. In this narrative review, through a fictional suggestive case of DS PTB, we guide the reader in a step-by-step commentary to provide an updated review of current evidence in the management of TB, from diagnosis to post-treatment follow-up. World Health Organization and Centre for Diseases Control (CDC) guidelines for TB, as well as the updated literature, were used to support this manuscript.