Prognostic accuracy of time to sputum culture conversion in predicting cure in extensively drug-resistant tuberculosis patients: a multicentre retrospective observational study

Frequency, management and impact of adverse events on treatment outcomes in patients with multidrug resistant tuberculosis in Balochistan, Pakistan

Background

Early detection, monitoring, and managing adverse events (AEs) are crucial in optimising treatment for multidrug-resistant tuberculosis (MDR-TB) patients.

Objectives

To investigate the incidence, factors, management, and impact of AEs on treatment outcomes in MDR-TB patients.

Methods

This study reviewed the medical records of 275 MDR-TB patients at Fatimah Jinnah Institute of Chest Diseases in Quetta, Pakistan. Patient information was collected using a designed data collection form. Mann-Whitney U and Kruskal-Wallis tests examined the difference in AEs occurrences based on patients' characteristics. Multiple binary logistic regression identified factors associated with unsuccessful outcomes, with statistical significance set at a p-value < 0.05.

Results

Almost all patients (99.6%) experienced at-least one AE (median = 4/patient, interquartile range:3-6). The most common were GI disturbance (95.3%), arthralgia (80.4%), body pain and headache (61.8%), ototoxicity (61.4%), psychiatric disturbance (44%), hypokalaemia (40.4%), dermatological reactions (26.2%) and hypothyroidism (21.5%). AEs led to treatment modification in 7.3% patients. Educated patients, those with a history of TB treatment, previous use and resistance to any second-line drug had significantly higher number of AEs. A total of 64.0% were declared cured, 3.6% completed treatment, 19.6% died and 12.7.9% were lost to follow-up. Patients' age of 41-60(OR = 9.225) and >60 years(OR = 23.481), baseline body weight of 31-60 kg(OR = 0.180), urban residence(OR = 0.296), and experiencing ototoxicity (OR = 0.258) and hypothyroidism (OR = 0.136) were significantly associated with unsuccessful treatment outcomes.

Conclusion

AEs were highly prevalent but did not negatively impact treatment outcomes. Patients at higher risk of developing AEs and unsuccessful outcomes should receive special attention for its early management.

Effectiveness and safety of regimen containing bedaquiline and delamanid in patients with drug-resistant tuberculosis

Background

Bedaquiline and delamanid have been included in the individualized treatment regimen (ITR) to treat patients with drug-resistant tuberculosis (DR-TB).

Objective

The objective of this study is to compare the effectiveness of sputum culture conversion and the safety of ITR containing bedaquiline and delamanid.

Methods

Data were collected retrospectively from medical records of DR-TB patients who received ITR between January 2020 and December 2021. Patients were divided into bedaquiline and bedaquiline-delamanid groups. Sputum culture was evaluated until 6 months of treatment. Measurement of QTc interval, renal and liver function test, and serum potassium were evaluated to assess safety during the study period. We used Chi-square to analyze a difference in cumulative culture conversion; meanwhile, Wilcoxon and Mann-Whitney tests were used to analyze differences in laboratory data for each and between the two groups, respectively.

Results

Fifty-one eligible DR-TB patients met the inclusion criteria, 41 in the bedaquiline and 10 in bedaquiline-delamanid group. 43/51 patients had a positive culture at baseline. After 6 months of treatment, 42/43 DR-TB patients (97.6%) had sputum culture conversion and no difference between the two groups (P ≥ 0.05). QTc interval within normal limit and no patient had a QTc >500 ms during the study period. Creatinine levels significantly differed between the two groups 6 months after treatment (P < 0.05).

Conclusion

DR-TB patients who received all oral ITR containing bedaquiline and or delamanid demonstrated favorable sputum conversion with a tolerable safety profile.

Why do patients with DR-TB do not complete their treatment? Findings of a qualitative study from Pakistan

BACKGROUND

One of the major reasons for unsuccessful treatment outcomes among patients with drug-resistant tuberculosis (DR-TB) is the high rate of loss to follow-up (LTFU). However, in Pakistan, no qualitative study has been conducted to explore the perceptions of LTFU patients with regard to DR-TB treatment, the problems they face and the reasons for LTFU in detail.

METHODS

This was a qualitative study that involved semistructured, indepth, face-to-face interviews of 39 LTFU patients with DR-TB. All interviews were carried out in Pakistan's national language 'Urdu' using an interview guide in two phases: the first phase was from December 2020 to February 2021 among patients with extensively drug-resistant tuberculosis and the second phase from July 2021 to September 2021 among patients with multidrug-resistant tuberculosis.

RESULTS

The inductive thematic analysis of audio-recorded interviews generated the following four key themes, which were the major reasons reported by the participants of the current study to have led to LTFU: (1) patient-related factors, such as lack of awareness about the total duration of DR-TB treatment, fatigue from previous multiple failed episodes, lack of belief in treatment efficacy and perception of DR-TB as a non-curable disease; (2) medication-related factors, such as use of injectables, high pill burden, longer duration and adverse events; (3) socioeconomic factors, such as gender discrimination, poor socioeconomic conditions, non-supportive family members, social isolation and unemployment; and (4) service provider-related factors, such as distant treatment centres, non-availability of a qualified person, lack of adequate counselling and poor attitude of healthcare professionals.

CONCLUSION

In the current study, patients' perceptions about DR-TB treatment, socioeconomic condition, medication and service provider-related factors emerged as barriers to the successful completion of DR-TB treatment. Increasing patients' awareness about the duration of DR-TB treatment, interacting sessions with successfully treated patients, availability of rapid drug susceptibility testing facilities at treatment centres, decentralising treatment and using the recently recommended all-oral regimen may further decrease the rate of LTFU.

The efficacy and safety of high-dose isoniazid-containing therapy for multidrug-resistant tuberculosis: a systematic review and meta-analysis

Objectives: Accumulating evidence are available on the efficacy of high-dose isoniazid (INH) for multidrug-resistant tuberculosis (MDR-TB) treatment. We aimed to perform a systematic review and meta-analysis to compare clinical efficacy and safety outcomes of high-dose INH- containing therapy against other regimes. Methods: We searched the following databases PubMed, Embase, Scopus, Web of Science, CINAHL, the Cochrane Library, and ClinicalTrials.gov. We considered and included any studies comparing treatment success, treatment unsuccess, or adverse events in patients with MDR-TB treated with high-dose INH (>300 mg/day or >5 mg/kg/day). Results: Of a total of 3,749 citations screened, 19 studies were included, accounting for 5,103 subjects, the risk of bias was low in all studies. The pooled treatment success, death, and adverse events of high-dose INH-containing therapy was 76.5% (95% CI: 70.9%-81.8%; I2: 92.03%), 7.1% (95% CI: 5.3%-9.1%; I2: 73.75%), and 61.1% (95% CI: 43.0%-77.8%; I2: 98.23%), respectively. The high-dose INH administration is associated with significantly higher treatment success (RR: 1.13, 95% CI: 1.04-1.22; p < 0.01) and a lower risk of death (RR: 0.45, 95% CI: 0.32-0.63; p < 0.01). However, in terms of other outcomes (such as adverse events, and culture conversion rate), no difference was observed between high-dose INH and other treatment options (all p > 0.05). In addition, no publication bias was observed. Conclusion: In MDR-TB patients, high-dose INH administration is associated with a favorable outcome and acceptable adverse-event profile. Systematic review registration: identifier CRD42023438080.

Comparative effectiveness of individualized longer and standardized shorter regimens in the treatment of multidrug resistant tuberculosis in a high burden country

Objective: To compare the effectiveness of second line injectables containing shorter (duration 9–12 months) and longer treatment regimens (LTR, duration ≥ 20 months) among multidrug-resistant tuberculosis (MDR-TB) patients with no documented resistance and history of treatment with any second-line anti-TB drug (SLD) for ≥ 1 month.

Methods: This was an observational cohort study of MDR-TB patients treated at eight PMDT units in Pakistan. Patients’ data from baseline until treatment outcomes were collected from Electronic Nominal Recording and Reporting System. The treatment outcomes of “cured” and “treatment completed” were grouped together as successful, whereas “death,” “treatment failure,” and “lost to follow-up” were collectively grouped as unsuccessful outcomes. Time to sputum culture conversion (SCC) was analyzed using the Kaplan–Meier method and the differences between groups were compared through the log-rank test. Multivariate Cox proportional hazards and binary logistic regression analyses were used to find predictors of time to SCC and unsuccessful treatment outcomes. A p-value < 0.05 was considered statistically significant.

Results: A total 701 eligible MDR-TB patients [313 treated with shorter treatment regimen (STR) and 388 treated with LTR at eight centres in Pakistan were evaluated]. Time to achieve SCC was significantly shorter in STR group [mean: 2.03 months, 95% confidence interval (CI):1.79–2.26] than in LTR group (mean: 2.69 months, 95% CI: 2.35–3.03) (p-value<0.001, Log-rank test). Treatment success was higher in STR (83.7%) than in LTR (73.2%) group (p-value <0.001) due to high cure (79.9% vs. 70.9%, p-value = 0.006) and low death (9.9% vs. 18.3%, p-value = 0.002) rates with STR. Treatment with STR emerged the only predictor of early SCC [adjusted Hazards ratio (aHR) = 0.815, p-value = 0.014], whereas, patient’s age of 41–60 (OR = 2.62, p-value<0.001) and >60 years (OR = 5.84, p-value<0.001), baseline body weight of 31–60 (OR = 0.36, p-value = 0.001) and >60 kg (OR = 0.23, p-value <0.001), and treatment with LTR (OR = 1.88, p-value = 0.001) had statistically significant association with unsuccessful treatment outcomes.

Conclusion: STR exhibited superior anti-microbial activity against MDR-TB. When compared LTR, treatment with STR resulted in significantly early SCC, high cure, and lower death rates among MDR-TB patients who had no documented resistance and history of treatment with any SLD ≥ 1 month.

Reduction of blood C-reactive protein concentration complements the resolution of sputum bacillary load in patients on anti-tuberculosis therapy

Background

Tuberculosis (TB) is a difficult-to-treat disease requiring the combination of four antibiotics for a minimum of 6 months. Rapid and quantitative biomarkers to monitor treatment response are urgently needed for individual patient management and clinical trials. C-reactive protein (CRP) is often used clinically as a rapid marker of inflammation caused by infection. We assessed the relationship of TB bacillary load and CRP as biomarkers of treatment response.

Methods

Xpert MTB/RIF-confirmed pulmonary TB cases were enrolled for treatment response assessment in Mozambique. Treatment response was measured using the Tuberculosis Molecular Bacterial Load Assay (TB-MBLA) in comparison with standard-of-care Mycobacterium Growth Indicator Tube (MGIT) culture at baseline and at weeks 1, 2, 4, 8, 12, 17, and 26 of treatment. Blood CRP concentration was measured at baseline, week 8, and week 26. Treatment response was defined as increase in MGIT culture time to positivity (TTP), and reduction in TB-MBLA-measured bacillary load and blood CRP concentration.

Results

Out of the 81 screened presumptive TB cases, 69 were enrolled for 6-month treatment follow-up resulting in 94% treatment completion rate. Four participants did not complete TB treatment and 22 participants had missing CRP or TB-MBLA results and were excluded from TB-MBLA-CRP analysis. The remaining 43 participants-median age, 31 years old [interquartile range (IQR): 18-56]; 70% (30/43) male; and 70% (30/43) infected with HIV-were considered for analysis. Culture TTP and bacillary load were inversely correlated, Spearman's r = -0.67, p < 0.0001. Resolution of sputum bacillary load concurred with reduction of blood CRP, r = 0.70, p < 0.0001. At baseline, bacillary load had a median (IQR) of 6.4 (5.5-7.2), which reduced to 2.4 (0.0-2.9) and 0.0 (0.0-0.0) log₁₀ CFU/ml at months 2 and 6 of treatment, respectively. Correspondingly, blood CRP reduced from 1.9 (1.6-2.1) at baseline to 1.3 (0.9-1.7) and 0.4 (0.1-0.8) log₁₀ mg/dl at months 2 and 6 of treatment, respectively. CRP reduction trialed bacteriological resolution at a rate of -0.06 log₁₀ mg/dl compared to a bacillary load of 0.23 log₁₀ CFU/ml per week. Consequently, 14 (33%) and 37 (88%) patients had reduced CRP to normal concentration and bacillary load to zero by the end of treatment, respectively. Pre-treatment CRP concentration and bacillary load, and resolution during treatment were slightly lower in HIV co-infected patients but not significantly different from HIV-uninfected TB patients.

Conclusion

TB-MBLA-measured bacillary load and blood CRP complement each other in response to anti-TB therapy. Slow CRP reduction probably reflects residual TB bacilli in the lung not expectorated in sputum. Combining both measures can improve the accuracy of these biomarkers for monitoring TB treatment response and shorten turnaround time since the results of both assays could be available in 24 h.