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.

Enteropathogen spectrum and effect on antimycobacterial pharmacokinetics among children with tuberculosis in rural Tanzania: a prospective cohort study.

BACKGROUND: Enteropathy is prevalent in tuberculosis-endemic areas, and it has been shown to impair intestinal absorptive function; therefore, enteropathogen burden might negatively affect antimycobacterial pharmacokinetics, particularly among malnourished children. We sought to quantify enteropathogen burden among children initiating tuberculosis treatment in rural Tanzania and determine the effect of enteropathogen burden on serum antimycobacterial pharmacokinetics. METHODS: We performed a prospective cohort study at one site in rural Tanzania as an exploratory substudy of a large multicountry cohort study. We included children younger than 15 years of age with confirmed or probable tuberculosis undergoing treatment with first-line tuberculosis therapy; children were excluded from the study if they were unable to undergo sample collection. Participants were consecutively recruited from the inpatient paediatric wards or the outpatient tuberculosis clinic at Haydom Lutheran Hospital, Tanzania. The main outcome was to quantify symptomatic enteropathogen burden and the effect on serum antimycobacterial pharmacokinetics. We quantified enteropathogen burden (defined as the sum of distinct enteropathogens detected in stool) using a multipathogen PCR capable of simultaneous detection of 37 bacterial, viral, and parasitic species or species groups from stool collected within 72 h of treatment initiation. Comprehensive clinical assessment, including presence of gastrointestinal symptoms, was performed at baseline, and serum was collected approximately 2 weeks after treatment initiation at steady state and throughout the dosing interval with concentrations of isoniazid, rifampicin, pyrazinamide, and ethambutol measured by liquid chromatography with a tandem mass spectrometry assay to quantify peak (Cmax) and total area under the concentration curve (AUC0-24), as determined by non-compartmental analysis. Enteropathogen burden was compared with pharmacokinetic measurements using bivariable and multivariable linear regression. FINDINGS: 58 children were assessed for eligibilty and enrolled between June 25, 2016, and Feb 6, 2018; 44 had complete stool testing and serum pharmacokinetic data, and they were included in the analyses. 20 (45%) were female, and 24 (55%) were male. 37 (84%) had moderate or severe malnutrition. A mean of 2·1 (SD 1·3) enteropathogens were detected per participant. Target peak concentrations of rifampicin were reached in eight (18%) of 44 participants, isoniazid in 24 (54%) of 44 participants, pyrazinamide in 28 (74%) of 38 participants, and ethambutol in six (15%) of 39 participants. Compared with controlled comparisons, each summative additional bacterial enteropathogen detected was associated with a 40% lower rifampicin Cmax (95% CI -62 to -5) and a 36% lower ethambutol Cmax (-52 to -14), while viral pathogens were associated with a 51% lower isoniazid Cmax (-75 to -7). The combination of gastrointestinal symptoms and detection of an additional enteropathogen was associated with a 27% reduction in rifampicin AUC0-24 (95% CI -47 to -1). INTERPRETATION: Tanzanian children undergoing tuberculosis treatment rarely attained pharmacokinetic targets; enteropathogen carriage was common and enteropathogen burden was associated with significant reductions in the concentrations of some antimycobacterial drugs. Further research should explore mechanistic relationships of individual pathogens and antimycobacterial pharmacokinetics in larger cohorts, or determine if screening for and treating enteropathogens at tuberculosis treatment initiation improves pharmacokinetic target attainment. FUNDING: National Institute of Allergy and Infectious Diseases, National Institutes of Health. TRANSLATION: For the Swahili translation of the abstract see Supplementary Materials section.

Determination of Rifampin Concentrations by Urine Colorimetry and Mobile Phone Readout for Personalized Dosing in Tuberculosis Treatment.

BACKGROUND: Individual pharmacokinetic variability is a driver of poor tuberculosis (TB) treatment outcomes. We developed a method for measurement of rifampin concentrations by urine colorimetry and a mobile phone photographic application to predict clinically important serum rifampin pharmacokinetic measurements in children treated for TB. METHODS: Among spiked urine samples, colorimetric assay performance was tested with conventional spectrophotometric and the mobile phone/light box methods under various environmental and biologic conditions. Urine rifampin absorbance (Abs) was then determined from timed specimens from children treated for TB in Tanzania, and compared to serum pharmacokinetic measurements collected throughout the dosing interval. RESULTS: Both the mobile phone/light box and spectrophotometry demonstrated excellent correlation across a wide range of urine rifampin concentrations (7.8-1000 mg/L) in intra- and interday trials, 24-hour exposure to ambient light or darkness, and varying urinalysis profiles (all r ≥ 0.98). In 12 Tanzanian children, the urine mobile phone/light box measurement and serum peak concentration (Cmax) were significantly correlated (P = .004). Using a Cmax target of 8 mg/L, the area under the receiver operating characteristic curve was 80.1% (range, 47.2%-100%). A urine mobile phone/light box threshold of 50 Abs correctly classified all patients (n = 6) with serum measurements below target. CONCLUSIONS: The urine colorimetry with mobile phone/light box assay accurately measured rifampin absorbance in varying environmental and biological conditions that may be observed clinically. Among children treated for TB, the assay was sensitive for detection of low rifampin serum concentrations. Future work will identify the optimal timing for urine collection, and operationalize use in TB-endemic settings.

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.