Rifampin urinary excretion to predict serum targets in children with tuberculosis: a prospective diagnostic accuracy study

OBJECTIVE

Pharmacokinetic variability drives tuberculosis (TB) treatment outcomes but measurement of serum drug concentrations for personalised dosing is inaccessible for children in TB-endemic settings. We compared rifampin urine excretion for prediction of a serum target associated with treatment outcome.

DESIGN

Prospective diagnostic accuracy study.

SETTING

Inpatient wards and outpatient clinics, northern Tanzania.

PATIENTS

Children aged 4-17 years were consecutively recruited on initiation of WHO-approved treatment regimens.

INTERVENTIONS

Samples were collected after directly observed therapy at least 2 weeks after initiation in the intensive phase: serum at pre-dose and 1, 2 and 6 hours post-dose, later analysed by liquid chromatography-tandem mass spectrometry for calculation of rifampin total exposure or area under the concentration time curve (AUC0-24); urine at post-dose intervals of 0-4, 4-8 and 8-24 hours, with rifampin excretion amount measured onsite by spectrophotometry.

MAIN OUTCOME MEASURES

Receiver operating characteristic (ROC) curve for percentage of rifampin dose excreted in urine measured by spectrophotometry to predict serum rifampin AUC0-24 target of 31.7 mg*hour/L.

RESULTS

89 children, 52 (58%) female, with median age of 9.1 years, had both serum and urine collection. Only 59 (66%) reached the serum AUC0-24 target, reflected by a range of urine excretion patterns. Area under the ROC curve for percentage of rifampin dose excreted in urine over 24 hours predicting serum AUC0-24 target was 69.3% (95% CI 56.7% to 81.8%), p=0.007.

CONCLUSIONS

Urine spectrophotometry correlated with a clinically relevant serum target for rifampin, representing a step toward personalised dosing for children in TB-endemic settings.

Duration of Symptoms Prior to Pediatric and Adolescent Tuberculosis Diagnosis and Its Impact on Schooling in Tanzania: A Mixed Methods Study

At least a third of tuberculosis (TB) cases remain undiagnosed, disproportionately so in children and adolescents, which is hampering global elimination goals. Prolonged symptom duration presents a high-risk scenario for childhood TB in endemic areas, but the prolonged period of symptoms and its impact on educational attainment are rarely documented. Using a mixed method approach, we aimed to quantify the duration of respiratory symptoms and describe their impact on education among children from a rural area of Tanzania. We used data from a prospectively enrolled cohort of children and adolescents aged 4-17 years in rural Tanzania at the start of active TB treatment. We report on the cohort's baseline characteristics and explore the correlation between duration of symptoms and other variables. In-depth qualitative interviews were designed on the basis of a grounded theory approach to explore the impact of TB on educational attainment among school-aged children. In this cohort, children and adolescents diagnosed with TB experienced symptoms for a median of 85 days (interquartile range: 30, 231 days) prior to treatment initiation. In addition, 56 participants (65%) had a TB exposure in the household. Of the 16 families with school-aged children who were interviewed, 15 (94%) reported a significant negative impact of TB on the schooling of their children. Children in this cohort experienced a long duration of TB symptoms; the extent of illness impacted absenteeism at school. Screening initiatives for households affected by TB may lead to a shortened duration of symptoms and may minimize the impact on school attendance.

Roadblocks and resilience: A qualitative study of the impact of pediatric tuberculosis on Tanzanian households and solutions from caregivers

Distinct from quantifying the economic sequelae of tuberculosis (TB) in adults, data are scarce regarding lived experiences of youth and their caregivers seeking and sustaining TB treatment in low income communities. Children ages 4-17 diagnosed with TB and their caregivers were recruited from rural and semi-urban northern Tanzania. Using a grounded theory approach, a qualitative interview guide was developed, informed by exploratory research. Twenty-four interviews were conducted in Kiswahili, audio-recorded and analyzed for emerging and consistent themes. Dominant themes found were socioemotional impacts of TB on households, including adverse effects on work productivity, and facilitators and obstacles to TB care, including general financial hardship and transportation challenges. The median percentage of household monthly income spent to attend a TB clinic visit was 34% (minimum: 1%, maximum: 220%). The most common solutions identified by caregivers to mitigate adverse impacts were transportation assistance and nutrition supplementation. To end TB, healthcare systems must acknowledge the total financial burden shouldered by low wealth families seeking pediatric TB care, provide consultations and medications locally, and increase access to TB-specific communal funds to mitigate burdens such as inadequate nutrition.Trial registration: planned sub-study of the registered prospective study, NCT05283967.Trial registration: ClinicalTrials.gov identifier: NCT05283967.

Pharmacokinetics of First-Line Drugs Among Children With Tuberculosis in Rural Tanzania

BACKGROUND

Dosing recommendations for treating childhood tuberculosis (TB) were revised by the World Health Organization, yet so far, pharmacokinetic studies that have evaluated these changes are relatively limited. We evaluated plasma drug concentrations of rifampicin (RIF), isoniazid (INH), pyrazinamide (PZA), and ethambutol (EMB) among children undergoing TB treatment in Tanzania when these dosing recommendations were being implemented.

METHODS

At the end of intensive-phase TB therapy, blood was obtained 2 hours after witnessed medication administration to estimate the peak drug concentration (C2h), measured using high-performance liquid chromatography or liquid chromatography-tandem mass spectrometry methods. Differences in median drug concentrations were compared on the basis of the weight-based dosing strategy using the Mann-Whitney U test. Risk factors for low drug concentrations were analyzed using multivariate regression analysis.

RESULTS

We enrolled 51 human immunodeficiency virus-negative children (median age, 5.3 years [range, 0.75-14 years]). The median C2hs were below the target range for each TB drug studied. Compared with children who received the "old" dosages, those who received the "revised" WHO dosages had a higher median C2h for RIF (P = .049) and PZA (P = .015) but not for INH (P = .624) or EMB (P = .143); however, these revised dosages did not result in the target range for RIF, INH, and EMB being achieved. A low starting dose was associated with a low C2h for RIF (P = .005) and PZA (P = .005). Malnutrition was associated with a low C2h for RIF (P = .001) and INH (P = .001).

CONCLUSIONS

Among this cohort of human immunodeficiency virus-negative Tanzanian children, use of the revised dosing strategy for treating childhood TB did not result in the target drug concentration for RIF, INH, or EMB being reached.