Scale-Up of Rifapentine and Isoniazid for Tuberculosis Prevention Among Household Contacts in 2 Urban Centers: An Effectiveness Assessment

BACKGROUND

Scaling up a shorter preventive regimen such as weekly isoniazid and rifapentine (3HP) for 3 months is a priority for tuberculosis (TB) preventive treatment (TPT). However, there are limited data on 3HP acceptability and completion from high-burden-TB countries.

METHODS

We scaled up 3HP from 2018 to 2021 in 2 cities in Pakistan. Eligible participants were household contacts of persons diagnosed with TB disease. Participants were prescribed 3HP after ruling out TB disease. Treatment was self-administered. We analyzed the proportion who completed 3HP.

RESULTS

In Karachi, we verbally screened 22 054 household contacts of all ages. Of these, 83% were clinically evaluated and 3% were diagnosed with TB. Of household contacts without TB disease, 59% initiated the 3HP regimen, of which 69% completed treatment. In Peshawar, we verbally screened 6389 household contacts of all ages. We evaluated 95% of household contacts, of whom 2% were diagnosed with TB disease. Among those without TB disease, 65% initiated 3HP, of which 93% completed. Factors associated with higher 3HP completion included residence in Peshawar (risk ratio [RR], 1.35 [95% confidence interval {CI}: 1.32-1.37]), index patient being a male (RR, 1.03 [95% CI: 1.01-1.05]), and index patient with extrapulmonary TB compared to bacteriologically positive pulmonary TB (RR, 1.10 [95% CI: 1.06-1.14]). The age of the index patient was inversely associated with completion.

CONCLUSIONS

We observed a high level of acceptance and completion of 3HP in programs implemented in 2 cities in Pakistan, with differences observed across the cities. These findings suggest that 3HP can be effectively scaled up in urban settings to improve the reach and impact of TPT.

Two Clinical Prediction Tools to Inform Rapid Tuberculosis Treatment Decision-making in Children

Background

In the absence of bacteriologic confirmation to diagnose tuberculosis (TB) in children, it is suggested that treatment should be initiated when sufficient clinical evidence of disease is available. However, it is unclear what clinical evidence is sufficient to make this decision. To identify children who would benefit from rapid initiation of TB treatment, we developed 2 clinical prediction tools.

Methods

We conducted a secondary analysis of a prospective intensified TB patient-finding intervention conducted in Pakistan in 2014-2016. TB disease was determined through either bacteriologic confirmation or a clinical diagnosis. We derived 2 tools: 1 uses classification and regression tree (CART) analysis to develop decision trees, while the second uses multivariable logistic regression to calculate a risk score.

Results

Of the 5162 and 5074 children included in the CART and prediction score, respectively, 1417 (27.5%) and 1365 (26.9%) were eligible for TB treatment. CART identified abnormal chest radiographs and family history of TB as the most important predictors (area under the receiver operating characteristic curve [AUC], 0.949). The final prediction score model included age group (0-4, 5-9, 10-14), weight <5th percentile, cough, fever, weight loss, chest radiograph suggestive of TB disease, and family history of TB; the identified best cutoff score was 9 (AUC, 0.985%).

Conclusions

Use of clinical evidence was sufficient to accurately identify children who would benefit from treatment initiation. Our tools performed well compared with existing algorithms, though these results need to be externally validated before operationalization.

Age-specific Clinical Presentation and Risk Factors for Extrapulmonary Tuberculosis Disease in Children

BACKGROUND

Clinical presentation for extrapulmonary tuberculosis (EPTB) in children can be variable and nonspecific, leading to delayed diagnosis, disease and death. We describe the age-specific clinical presentation and identify risk factors for EPTB among children in Pakistan.

METHODS

In 2015-2016 in 4 facilities in Sindh, Pakistan, children were diagnosed with TB either through bacteriologic confirmation or clinical-radiologic criteria. EPTB comprised any form of TB disease that did not involve the lungs. Among children with TB disease, we report demographics, clinical characteristics and symptoms, family medical history and diagnostic test results for children with and without EPTB. We conduct age-specific regression analyses to identify factors associated with an EPTB diagnosis among children age 0-4, 5-9 and 10-14 years.

RESULTS

A total of 1163 children were diagnosed with TB disease, of which 157 (13.5%) had EPTB. Of those, 46 (29.3%) were 0-4, 53 (33.8%) were 5-9 and 58 (36.9%) were 10-14 years old. Of children with EPTB, the most frequently reported sites were lymph node (113, 72.4%) and abdominal (31, 19.9%). Weight loss was associated with an increased risk of EPTB in the 0-4-year-old (adjusted odds ratio: 2.80, 95% confidence interval: 1.05-7.47) and 10-14-year-old (adjusted odds ratio: 2.79, 95% confidence interval: 1.28-6.07) groups, and the presence of cough was associated with a decreased risk of EPTB.

CONCLUSIONS

This study provides new knowledge about age-specific clinical presentation and risk factors of EPTB in children in Pakistan. Our results can help to optimize clinical algorithms designed to achieve a timely diagnosis in children with EPTB along with improved treatment outcomes.

Implementing 3HP vs. IPT as TB preventive treatment in Pakistan

BACKGROUND: We assessed treatment uptake and completion for 6 months of isoniazid (6H) and 3 months of isoniazid plus rifapentine weekly (3HP) in a programmatic setting in Pakistan.METHODS: All household contacts were clinically evaluated to rule out TB disease. 6H was used for TB preventive treatment (TPT) from October 2016 to April 2017; from May to September 2017, 3HP was used for contacts aged ≥2 years. We compared clinical evaluation, TPT uptake and completion rates between contacts aged ≥2 years in the 6H period and in the 3HP period.RESULTS: We identified 3,442 contacts for the 6H regimen. After clinical evaluation, 744/1,036 (72%) started treatment, while 46% completed treatment. In contrast, 3,722 contacts were identified for 3HP. After clinical evaluation, 990/1,366 (72%) started treatment, while 67% completed treatment. Uptake of TPT did not differ significantly between the 6H and 3HP groups (OR 1.03, 95%CI 0.86-1.24). However, people who initiated 3HP had 2.3 times greater odds (95% CI 1.9-2.8) of completing treatment than those who initiated 6H after adjusting for age and sex.CONCLUSION: In programmatic settings in a high-burden country, household contacts of all ages were more likely to complete TPT with shorter weekly regimens, although treatment uptake rate for the two regimens was similar.

Cost of Delivering 12-Dose Isoniazid and Rifapentine Versus 6 Months of Isoniazid for Tuberculosis Infection in a High-Burden Setting

BACKGROUND

Successful delivery and completion of tuberculosis preventive treatment are necessary for tuberculosis elimination. Shorter preventive treatment regimens currently have higher medication costs, but patients spend less time in care and are more likely to complete treatment. It is unknown how economic costs of successful delivery differ between longer and shorter regimens in high-tuberculosis-burden settings.

METHODS

We developed survey instruments to collect costs from program and patient sources, considering costs incurred from when household contacts first entered the health system. We compared the cost per completed course of preventive treatment with either 6 months of daily isoniazid (6H) or 3 months of weekly isoniazid and rifapentine (3HP), delivered by the Indus Health Network tuberculosis program in Karachi, Pakistan, between October 2016 and February 2018.

RESULTS

During this period, 459 individuals initiated 6H and 643 initiated 3HP; 39% and 61% completed treatment, respectively. Considering costs to both the program and care recipients, the cost per completed course was 394 US dollars (USD) for 6H and 333 USD for 3HP. Using a new 2020 price for rifapentine reduced the cost per completed course of 3HP to 290 USD. Under varying assumptions about drug prices and costs incurred by care recipients, the cost per completed course was lower for 3HP in all scenarios, and the largest cost drivers were the salaries of clinical staff.

CONCLUSIONS

In a high-burden setting, the cost of successful delivery of 3HP was lower than that of 6H, driven by higher completion.

Risk Factors for Adverse Events in Household Contacts Prescribed Preventive Treatment for Drug-resistant Tuberculosis Exposure

BACKGROUND

Completion of tuberculosis (TB) preventive treatment is important to optimize efficacy; treatment-related adverse events (AEs) sometimes result in discontinuation. This study describes the occurrence of AEs and their risk factors during a 6-month, 2-drug, fluoroquinolone-based preventive treatment for household contacts of patients with drug-resistant TB in Karachi, Pakistan.

METHODS

The primary outcome was development of any clinical AE during preventive treatment. Adverse events were categorized using the AE grading tables of the National Institutes of Health. Time-to-event analysis with Kaplan-Meier curves and Cox proportional hazards models accounting for recurrence were used to analyze associated risk factors.

RESULTS

Of the 172 household contacts on preventive treatment, 36 (21%) developed 64 AEs during 813 months of treatment. The incidence of AEs over 6 months of treatment was 7.9 per 100 person-months; 16 per 100 person-months with a fluoroquinolone and ethionamide, and 4.4 per 100 person-months with a fluoroquinolone and ethambutol. There were 53 (83%) grade 1 and 11 grade 2 AEs, with no grade 3 or 4 AEs. In multivariable analysis, the risk of AEs was higher in contacts prescribed ethionamide as compared to ethambutol adjusting for age, sex, and body mass index (adjusted hazard ratio, 2.1 [95% confidence interval {CI}, 1.2-3.6]). Overall, there was no notable difference in treatment completion among the contacts who experienced an AE and those who did not (crude odds ratio, 1.1 [95% CI, .52-2.5]).

CONCLUSIONS

A fluoroquinolone-based preventive treatment regimen for drug-resistant TB exposure is well tolerated. Regimens with ethionamide are more likely to result in AEs.

Safety and feasibility of 1 month of daily rifapentine plus isoniazid to prevent tuberculosis in children and adolescents: a prospective cohort study

BACKGROUND

Shorter regimens for tuberculosis prevention can improve completion rates and protection against developing active tuberculosis disease after tuberculosis exposure. We aimed to assess the safety and feasibility of 1 month of daily isoniazid and rifapentine (1HP) in children and adolescents in a low-resource setting in south Asia with low prevalence of HIV.

METHODS

This prospective cohort study was done in eight tuberculosis facilities in Karachi, Pakistan. Eligible participants were aged 2-19 years and were household contacts of patients with drug-susceptible tuberculosis infection. After clinical, radiological, and laboratory evaluation to rule out tuberculosis disease, participants were prescribed 1HP as a preventive regimen. Isoniazid was administered as 100 mg or 300 mg oral tablets and rifapentine was administered as 150 mg oral tablets. Dosing was according to participant bodyweight. The primary endpoints were the cumulative probability of a household contact completing all stages of the preventive care cascade, assessed in all eligible participants, and the proportion of household contacts completing 1HP, assessed among all those who initiated the regimen. Safety was assessed in all household contacts who initiated the 1HP regimen.

FINDINGS

Between Dec 21, 2019, and March 20, 2020, 1395 household contacts of 253 patients with tuberculosis were identified, including 678 household contacts who were eligible to participate. 628 (93%) completed evaluation, of whom ten (2%) had active tuberculosis disease. Of the 618 individuals eligible for tuberculosis prevention, 408 (66%) initiated 1HP, 385 (94%) of whom completed the regimen. The median duration of 1HP was 31 days (IQR 30-32) in those who completed the regimen. The cumulative probability of completing all steps of the tuberculosis prevention cascade was 58%. A girl aged 11 years developed tuberculosis disease within 6 months of completing 1HP. A boy aged 14 years developed a burning sensation during 1HP therapy and discontinued the regimen. No other adverse events were observed.

INTERPRETATION

1HP can be safely and feasibly implemented as tuberculosis prevention in children and adolescents in programmatic settings.

FUNDING

The Global Fund to Fight AIDS, Tuberculosis and Malaria.

Predictors of unsuccessful tuberculosis treatment outcomes in children from a prospective cohort study in Pakistan

Background

Every year, about 239 000 children die from tuberculosis (TB), despite availability of highly effective regimens. Few studies have evaluated predictors for poor treatment outcomes in children treated for TB.

Methods

We assessed predictors of unsuccessful TB treatment outcomes in a prospective cohort of children diagnosed by an intensified TB patient-finding intervention at four facilities in Pakistan between 2014 and 2016. A case of TB disease was determined through either bacteriologic confirmation of disease or a clinical diagnosis. To estimate characteristics predictive of experiencing an unsuccessful treatment outcome, we used a multi-level model with a modified Poisson approach, accounting for clustering at the facility level. We report estimated relative risks (RR) and 95% confidence intervals (CI).

Results

During the study period, 1404 children less than 15 years old were initiated on treatment for drug-susceptible TB. In total, 709 (50.5%) were 0-4, 406 (28.9%) were 5-9 years, and 289 (20.6%) were 10-14 years old; 614 (43.7%) were female; and of the 1377 children assessed for malnourishment, 1161 (84.3%) were malnourished. A total of 1322 (94.2%) children experienced a successful treatment outcome, 14 (1.0%) children transferred out to a different facility, and 68 (4.8%) children experienced an unsuccessful treatment outcome: 14 (1.0%) died, 20 (1.4%) failed treatment, and 34 (2.4%) were lost to follow-up. After adjustment for age group, sex, and malnutrition status, we identified increased risk of unsuccessful treatment outcome in children presenting with fever (RR = 2.56, 95% CI = 1.02-6.44; P = 0.05) or an abdominal examination suggestive of TB disease (RR = 2.34, 95% CI = 1.20-4.58; P = 0.01), and a decreased risk in children who initiated treatment at a rural facility (RR = 0.05, 95% CI = 0.00-0.74; P = 0.03).

Conclusions

More than 94% of children experienced successful treatment outcomes. We identified individual-, facility-, and clinical-factors predictive of experiencing unsuccessful treatment outcomes. Children with fevers and abdominal findings suggestive of TB disease should be tested for TB and followed closely throughout treatment to ensure necessary support for successful completion of treatment.

Tuberculosis Preventive Therapy for Individuals Exposed to Drug-resistant Tuberculosis: Feasibility and Safety of a Community-based Delivery of Fluoroquinolone-containing Preventive Regimen

BACKGROUND

Observational studies have demonstrated the effectiveness of a fluoroquinolone-based regimen to treat individuals presumed to be infected with drug-resistant tuberculosis (DR-TB). We sought to assess the feasibility of this approach in an urban setting in South Asia.

METHODS

From February 2016 until March 2017, all household contacts of DR-TB patients enrolled at the Indus Hospital were screened for TB symptoms at home. Children aged 0-17 years, symptomatic adults, and those with an immunocompromising condition (human immunodeficiency virus, diabetes, or malnutrition) were evaluated for TB disease. Contacts diagnosed with TB disease were started on treatment. Contacts without TB disease aged <5 years, contacts aged between 5 and 17 years with either a positive tuberculin skin test or an immunocompromising condition, or contacts aged ≥18 years with an immunocompromising condition were offered 6 months of treatment with a fluoroquinolone.

RESULTS

One hundred households with 800 contacts were enrolled: 353 (44.1%) individuals aged ≤17 years with a median age of 19 years (interquartile range, 10-32); 423 (52.9%) were males. In total, 737 (92.1%) individuals were screened, of which 8 were already on treatment for TB (1.1%); another 3 (0.4%) contacts were diagnosed with TB disease and started on treatment. Of 215 eligible for infection treatment, 172 (80.0%) contacts initiated and 121 (70.3%) completed treatment. No TB disease or significant adverse events were observed during 12 months of follow-up.

CONCLUSIONS

Fluoroquinolone-based treatment for contacts with presumed DR-TB infection is feasible and well tolerated in a high TB burden setting.

Improving childhood tuberculosis detection and treatment through facility-based screening in rural Pakistan

SETTING

Many children with tuberculosis (TB) remain undiagnosed due to the absence of services, lack of child-friendly diagnostics and underappreciation of TB as a common cause of childhood illness.

OBJECTIVE

To show the impact of systematic verbal screening and contact tracing with appropriate management services on TB case finding in pediatric populations.

DESIGN

Between October 2014 and March 2016, children were verbally screened at the pediatric out-patient departments of four public hospitals in Jamshoro District, Pakistan. Children with symptoms or risk of TB were referred for clinical evaluation and free chest X-ray and bacteriological tests. Children with TB were started on treatment and their care givers asked to bring household members to the hospital for screening.

RESULTS

Over 105 000 children were verbally screened and 5880 presumptive childhood TB patients were identified; 1417 children (prevalence 1.3%) were diagnosed with TB; 43% were female. The median age was 5 years; 82% had pulmonary TB. An additional 390 children with TB were diagnosed through contact tracing. These activities resulted in a three-fold increase in pediatric TB case notifications.

CONCLUSION

Systematic verbal screening with clinical evaluation and free diagnostics can identify children with TB who may otherwise be missed in rural health settings.

Factors associated with month 2 smear non-conversion among Category 1 tuberculosis patients in Karachi, Pakistan

Predictors of smear non-conversion at baseline can help identify cases at risk for failure of tuberculosis treatment. Retrospective data for smear-positive Category 1 patients in Karachi, Pakistan, was analyzed. Predictors of sputum conversion were determined using multiple logistic regression with sputum conversion as outcome variable and patient demographics, baseline weight, baseline sputum smear grade, case-finding approach as explanatory variables. Age ≥35 years, baseline sputum grade of 3+ were significantly associated with predicting sputum smear positivity at month 2 of treatment. Monitoring compliance to TB treatment should be considered amongst older patients and those with a high sputum grade at baseline.

Determinants of Default from Tuberculosis Treatment among Patients with Drug-Susceptible Tuberculosis in Karachi, Pakistan: A Mixed Methods Study

Purpose

Non-adherence to tuberculosis therapy can lead to drug resistance, prolonged infectiousness, and death; therefore, understanding what causes treatment default is important. Pakistan has one of the highest burdens of tuberculosis in the world, yet there have been no qualitative studies in Pakistan that have specifically examined why default occurs. We conducted a mixed methods study at a tuberculosis clinic in Karachi to understand why patients with drug-susceptible tuberculosis default from treatment, and to identify factors associated with default. Patients attending this clinic pick up medications weekly and undergo family-supported directly observed therapy.

Methods

In-depth interviews were administered to 21 patients who had defaulted. We also compared patients who defaulted with those who were cured, had completed, or had failed treatment in 2013.

Results

Qualitative analyses showed the most common reasons for default were the financial burden of treatment, and medication side effects and beliefs. The influence of finances on other causes of default was also prominent, as was concern about the effect of treatment on family members. In quantitative analysis, of 2120 patients, 301 (14.2%) defaulted. Univariate analysis found that male gender (OR: 1.34, 95% CI: 1.04–1.71), being 35–59 years of age (OR: 1.54, 95% CI: 1.14–2.08), or being 60 years of age or older (OR: 1.84, 95% CI: 1.17–2.88) were associated with default. After adjusting for gender, disease site, and patient category, being 35–59 years of age (aOR: 1.49, 95% CI: 1.10–2.03) or 60 years of age or older (aOR: 1.76, 95% CI: 1.12–2.77) were associated with default.

Conclusions

In multivariate analysis age was the only variable associated with default. This lack of identifiable risk factors and our qualitative findings imply that default is complex and often due to extrinsic and medication-related factors. More tolerable medications, improved side effect management, and innovative cost-reduction measures are needed to reduce default from tuberculosis treatment.