Study objective and endpoints
The primary objective of this study is to compare the proportion of household child TB contacts eligible for TPT who initiate and complete TPT under a facility-based standard of care and under a decentralized community-based intervention model of care for contact screening and management.
The corresponding primary endpoint is the proportion of child TB contacts < 5 years of age and HIV-infected children of 5–14 years of age who initiate and complete the TPT declared by the index case.
The secondary objectives compare the aforementioned models in terms of: i) cascade of care of TPT initiation and completion in child contacts < 5 years or HIV positive children 5–14 years; ii) cascade of care for TB detection and treatment in all included contacts; iii) tolerability and adherence in children initiated on TPT; iv) acceptability and feasibility of the two models by the parents/guardians, health personnel and community; v) the effect of the community based intervention on the number of adult contacts diagnosed with TB; and the cost-effectiveness. The number of children and adults diagnosed with TB and the number of children initiated on TPT will be also compared before and after the intervention.
The secondary endpoints of the study are presented in Table 1 below:
Table 1
Secondary endpoints of the CONTACT study
General secondary endpoints | Detailed secondary endpoints |
Cascade of care for the initiation and completion of TPT of child contacts < 5 years or HIV-infected 5–14 years and reasons of dropouts at different steps of the cascade | Number of screened children and proportion of children screened among child contacts < 5 years or HIV-infected 5–14 years declared by the index case |
Proportion of children potentially eligible for TPT: TB disease excluded |
Proportion of children eligible for TPT after exclusion of contraindication to TPT |
Proportion of children started on TPT among those eligible for TPT |
Proportion of children who did not complete TPT among those started on TPT and reasons of interruptions |
Cascade of care for TB detection of child contacts | Proportion of children with symptoms suggestive of TB: presumptive TB |
Proportion of presumptive TB cases investigated for TB |
Proportion of children diagnosed with TB |
Proportion of children with TB diagnosis who are started on TB treatment |
Cascade of care for TB detection of adult contacts | Number of adults screened and proportion of adults screened among household identified adult contacts |
Proportion of adults with symptoms suggestive of TB: presumptive TB cases |
Proportion of adults presumptive TB cases diagnosed with TB. |
Safety and treatment adherence for children under TPT | Proportion of children with serious adverse events |
Proportion of children with adverse events of interest: peripheral neuropathy, clinical hepatotoxicity |
Ratio of dose taken as indicated (ticked) on the treatment card by the parent/guardian over the total number of doses to be taken by prescription. |
Endpoints at 6 months | Treatment outcomes of children started on TB treatment |
Proportion of children diagnosed with TB after initiation of TPT: during and after TPT |
Proportion of children diagnosed with TB among those who were not started on TPT and were not diagnosed with TB at baseline assessment. |
Before-after comparison for TB adult and pediatric cases and for TPT initiation and completion from health facility registers | Number of patients diagnosed with TB and registered |
Proportion of children among all patients diagnosed with TB and registered |
TB treatment outcomes of patients (adults and children) diagnosed with TB and registered |
Number of children started on TPT |
Completion rate of children started on TPT |
Acceptability and feasibility of the intervention | Attitudes, willingness and motivation to have a visit in their household |
Myths, anticipated fears, stigma and risks of having a visit in their household |
Actual experiences with household visits |
Perception of the disease, its risk and the notion of prevention, including TPT |
Description of critical events during house visits and how these where dealt with |
Identification of main constraints |
Fidelity of the study | Proportion of delivered activities compared to the intended activities of the model |
Cost-effectiveness of the intervention | Costs of CHW/community nurse assessment and treatment |
Costs of facility-based assessment and treatment |
Other facility costs (overheads, diagnosis, hospitalizations) |
Direct parent/guardian costs (related to care) |
Indirect parent/guardian costs (unrelated to care, e.g. dissaving, travel costs) |
Table 1: Secondary endpoints of the CONTACT study (see end of manuscript)
Study design
This is a two arm parallel cluster randomized study comparing two models of care for TB contact investigation and management. This study contains three phases:
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Baseline phase (phase I) in which retrospective data collection and register quality checks were done in order to assess if the facility registers could be a reliable source of documents for the study. During this phase there was also a baseline qualitative assessment with adult TB patients who are parents and stakeholders to better prepare the intervention phase and assess the acceptability and feasibility of the proposed activities.
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Intervention phase (phase II) includes implementation and participant recruitment in the two models of care and study data collection.
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Explanatory phase (phase III) contains the endpoint analysis and reporting, a cost-effectiveness analysis and a post-intervention qualitative assessment with adult TB patients who are parents and cluster stakeholders to collect the acceptability of the implemented package.
This research is known under the name of CONTACT study (Community Intervention for Tuberculosis Active Contact Tracing and Preventive Therapy) and represents a research project embedded in a multi-country pediatric TB implementation program called Catalyzing Pediatric TB Innovations (CaP TB) led by the Elizabeth Glaser Pediatric AIDS Foundation (EGPAF) and funded by Unitaid.
Study setting
This study is conducted in two high TB incidence, resource-limited African countries: Cameroon located in West Africa and Uganda in East Africa, with important differences in programmatic delivery of TB services. In Cameroon, TB care and management is centralized. Only secondary level health facilities have TB laboratory diagnostic facilities and TB patients can only access care and drugs from these health facilities. In Uganda, TB management is decentralized to the primary health care level. In both countries, national guidelines(28, 29) at the time of this study development recommended contact investigation and screening as well as TPT with 6 months of daily isoniazid (6H) for eligible children. However, coverage of TPT for eligible children below 5 years is low in both countries. WHO recently reported that only 24% and 15% of eligible children were initiated on TPT in 2018 in Cameroon and Uganda respectively (1).
Description of the intervention
Facility-based model
This model implements a “passive” approach to the screening and management of household contacts (see definition in “Study population” section) at the facility level as per current practice. Implementation follows current National tuberculosis program (NTP) recommendations, except that a 3-month regimen of daily rifampicin-isoniazid (3RH) as a fixed-dose combination is offered as TPT to eligible child contacts. In the context of the study, sites also benefit from additional data collection and trainings with follow-up support for the facility staff.
When a person is diagnosed with bacteriologically confirmed pulmonary TB (index case), the facility staff in charge of TB (TB focal person) asks the index case to bring all household contacts with TB-related symptoms, all young (< 5 years) child contacts or older (5–14 years) child contacts living with HIV or exposed to HIV, irrespective of symptoms, to the health facility for evaluation for TB disease or for eligibility for TPT. In Uganda, the NTP allows household contact tracing but evaluation, TPT initiation and follow-up are required to be done at the facility. At facility, TB investigations include clinical examination, sample collection for smear microscopy or Xpert MTB/RIF testing, and CXR when available and indicated, i.e. Xpert is negative or not done. Any contact diagnosed with TB is commenced on TB treatment, registered and provided with treatment support and follow-up as per NTP guidelines. Asymptomatic children who are eligible to receive TPT as 3RH (or 6H if drug-drug interactions with antiretroviral therapy preclude the use of rifampicin), are initiated at the facility with monthly follow-up. (Fig. 1). The schedule of the facility-based model is presented in Table 2.
Table 2
| BASELINE PHASE | INTERVENTION PHASE | EVALUATION PHASE |
| Allocation* | Site assessment** | Enrolment of index cases | Enrolment of contact cases | Follow-up | End of study | |
TIMEPOINT | | | -2W | 0 | W1 | W2 | W4 | W8 | W12** | W24 | |
ENROLMENT: | | | | | | | | | | | |
Eligibility screen | | | X | X | | | | | | | |
Informed consent | | | X | X | | | | | | | |
Allocation | X | | | | | | | | | | |
INTERVENTIONS: | | | | | | | | | | | |
Facility-based arm | | | X | X | | | X | X | X | X | |
Community-based arm | | | X | X | X | X | X | X | X | X | |
Qualitative assessment | | X | | | | | | | | | X |
CEA | | | | | X | | |
ASSESSMENTS: | | | | | | | | | | | |
Identification of contact children | | | X | | | | | | | | |
Children started on TPT | | | | X | | | | | | | |
Children completed TPT | | | | | | | | | X | X | |
Acceptability of the intervention | | X | | | | | | | | | X |
TPT cost | | | | | X | | |
*Allocation takes place before the intervention begins as the clusters are randomized and not the individuals |
**The baseline phase takes place 3 months before the intervention phase |
*** Children started on 6 months of isoniazid have 2 additional follow-up visits at week 16 and week 20 |
Abbreviations: W = week; CEA = cost effectiveness analysis; TPT = TB preventive therapy |
Community based model
The intervention model is a decentralized, “active” approach to the screening and management of household contacts and is community-based. When an index case is diagnosed with bacteriologically confirmed pulmonary TB, the TB focal person asks whether s/he has child contacts in the household, and if so, then asks whether s/he is willing to receive a team in his/her household for contact symptom screening. If they agree, then an appointment is made and a team comprising a trained community health worker (CHW) and a research assistant goes in the household to screen all contacts (children and adults). If the index case doesn’t have contact children in their household, then s/he is not included in the study, but contact investigation is done under routine care by the TB focal person. During the contact screening visit, the contacts who present symptoms of TB are referred to the health facility for TB investigations. Those who are asymptomatic and eligible for TPT (i.e. <5 years irrespective of HIV status or 5–14 years and living with HIV) receive another visit by the TB focal person or TB nurse to initiate 3RH (or 6H if drug-drug interactions with antiretroviral therapy preclude the use of rifampicin). The follow-up is done at the household by the CHW after one week, two weeks, and then monthly in order to rapidly identify the children who develop TB symptoms in the community. During the follow-up visits, the CHW repeats the TB symptom screening, assesses the child’s TPT tolerability and adherence and assesses presence of any critical sign. If the child presents critical danger signs, tolerability problems or TB symptoms, s/he is immediately referred to the health facility for a clinician to consult them. (Fig. 2). The schedule of the community-based model is presented in Table 2.
Table 2: SPIRIT study schedule (see end of manuscript for table and legend)
Study population
Bacteriologically confirmed (by smear microscopy, Xpert MTB/RIF or TB-LAMP assays) index cases, ≥ 15 years old who have been diagnosed less than a month prior to inclusion and declaring child contacts in the study catchment area are eligible. Exclusion criteria are: known MDR resistance, the index case being a prisoner or TB patients from an already screened household from the study.
Contacts sharing the same enclosed space for frequent or extended periods of time with the index case or having slept in the same bed during the last 3 months as per the WHO definition of a contact case (24), are eligible unless they are already on TPT or on TB treatment.
For the qualitative assessment the study population is represented by key informants (facility managers, health staff, community health workers and community leaders) and by male and female TB patients, who are parents/guardians.
Cluster selection and randomization
The study clusters are health facilities supported by the CaP TB Program with TB diagnostic and treatment capacity after an initial assessment taking into consideration the number of bacteriological index cases identified from January to December 2018 (minimum of 50). Priority was given to rural, semi-rural or semi-urban facilities as there is less population movement than in an urban setting with relatively easy access. In Cameroon, there were mainly district hospitals because TB diagnosis is mainly done at secondary health care level, with ten clusters selected from two regions (Central and Littoral regions). In Uganda, as TB services are decentralized at primary health care level, the ten clusters were PHC centers in four districts in South West region, some with two facilities per cluster in order to reach the minimum of 50 index cases per year.
The randomization was stratified by country and in each country, the 10 clusters have been allocated to one of the study models by a covariate constrained randomization(34) taking into account the number of bacteriologically confirmed TB cases from that cluster the previous year. The randomization was performed by a statistician from the central research team 3 months prior to the start of inclusions. Participants, healthcare providers, study staff and investigators are not blinded to the allocation of the health facilities.
The cluster list can be found in the Supplementary Material.
TPT
The 3RH regimen uses the child-friendly formulation of R75mg/H50mg as a fixed-dose combination(30) for eligible child contacts of < 25 kgs This formulation is procured and provided by the CaP TB project, as the NTP has not yet recommended this regimen, but has approved its use in the context of the study. Prescription is based on the body weight dose range as recommended by WHO(31). The body weight is measured at the TPT initiation visit and at the TPT outcome visit for both models and in the facility-based model it is measured at every follow-up visit. For children of 25 kgs or more, the adult RH tablet is be provided. For children receiving an antiretroviral treatment with protease inhibitors (as lopinavir/ritonavir), nevirapine or dolutegravir, 6H is used to avoid the drug-drug interaction between R and these antiretrovirals. Along with the TPT, 10 mg of daily pyridoxine (vitamin B6) is given to each child to prevent peripheral neuropathy.
Study procedures
Symptom screening
Both models use the following symptoms(32) to assess if the contact child has presumptive TB or not:
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Persistent non-remittent cough > 2 weeks
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Reported persistent fever > 10 days
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Reduced playfulness/lethargy/fatigue
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Wheezing > 2 weeks
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Night sweats > 2 weeks
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Documented or reported weight loss, loss of appetite or no weight gain (failure to thrive) in the last month
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Malnourishment using Mid-Upper Arm Circumference below 125 mm in children 6 months − 5 years old
The presence of at least one of these symptoms requires TB investigations at the health facility.
For HIV positive children, symptoms of any duration are suggestive of TB and the child is immediately referred to the clinic. HIV testing is proposed for the 5–14 years old children with unknown status using two rapid tests, as per national HIV testing guidance. In the community model the first test is done in the household and if positive, the confirmation test is done at the health facility.
In case a child presents a sign that is not yet suggestive of TB due to its duration (ex: cough for less than 2 weeks), the screening is repeated after two weeks’ time.
In addition to the screening for TB symptoms CHWs have been trained to identify critical signs for urgent referral in case the child needs to be seen urgently by a clinician. These signs are recommended by the Integrated Management of Childhood Illness Handbook of the WHO(33) and include: lethargy or unconsciousness, chest indrawing, difficulty breathing, sunken eyes, drinking poorly or not drinking, seizures, severe wasting, severe pallor, edema of both feet.
Adherence assessment
The adherence is assessed at each follow-up visit in both models of care using specific questions on how many doses were missed in the last 4 days, by counting the number of doses taken reported by the parent/guardian in a TPT treatment card introduced by the study and by verifying empty drug blister packs. Parent/guardian received treatment adherence counseling at TPT initiation and during follow-up based on treatment adherence.
Safety assessment
At each follow-up visit the children are assessed for TPT tolerability by CHW using a standard check list of signs suggestive of hepatitis, peripheral neuropathy and rash that are classically associated with HR (nausea, loss of appetite, vomiting, jaundice, dizziness, tingling or burning sensation in the extremities). In every cluster facility a clinician was trained to act as safety monitor and examine children with problems of tolerability identified by the CHW. In case of serious adverse events, the safety monitor immediately notifies the event to the country principal investigator who informs the sponsor and the ethics committee of the respective country. All adverse events and serious adverse events are coded using the MedDRA dictionary (version 22.1, September 2019). On a 6 months basis a safety data review is done by the study management team that is then reported to the sponsor and scientific advisory committee.
Sample size calculation
For the sample size calculation, we used an estimated 60% completion rate among the eligible children in the facility-based arm based on a recent systematic review (35) and a 10% difference in the community-based arm, considered to be the minimal clinically relevant difference. We consider a cluster coefficient variability of 50% and an intra-cluster correlation of 0.01. With these parameters, we would need to include at least 1500 declared child contacts by the index case who would be eligible to the TPT to have a power of 85%. The type I error rate α, is conventionally fixed at 0.05%. Based on national household statistics per country(36–38), we make the hypothesis of one child under 5 years per household. Looking at the index case TB registrations in the year prior to the intervention we estimate that it would be possible to include 1500 contact children in a 15 months period.
Data collection
Mixed methods of data collection, quantitative and qualitative, are used.
Quantitative data
Other than the facility registers, study specific source documents are used. The data for the primary and secondary objectives are collected by the TFP in the health facilities and community health workers in the community. There is one research assistant assigned to each cluster health facility who enters data onto tablets using the REDCap mobile application version 4.9.1, February 6th 2020. Patients’ cost data are collected by research assistants in the REDCap mobile application using an adapted version of the patient cost tool developed by the WHO(39). At the health system level, data are collected through literature, source documents from the Ministry of Health, primary expenditure analysis and procurement records by the cost analysis researchers.
Qualitative data
The data for the qualitative assessment is collected by the social researchers through in-depth interviews and focus group discussions in English, French or local language with the help of a local qualitative research assistant. Participants’ confidentiality and privacy are respected throughout the study. During the baseline phase of the study, a qualitative assessment of social determinants has been performed to identify the perceptions of TB, prevention for child contacts and obstacles for treatment, acceptability and feasibility of the proposed intervention. Focus group discussions have been organized with TB patients and in-depth interviews have been conducted with health staff, facility managers, CHW and community leaders. During the implementation phase, data on concurrent acceptability is assessed through periodic supervision meetings of the CHW. A second qualitative assessment will be performed at the end of the intervention focusing on the acceptability and lessons learned. These activities are planned in both models of care implemented in the study.
Process data
In the baseline phase, sites were assessed in terms of quality of data collection in the registers and specific practices that would require adjustments for study organization of those sites. During the implementation phase, recruitment logs are filled in by research assistants to document study screening and enrolment process with reasons of refusal.
Data management
A central data manager coordinates with local data managers to ensure the data entry and verification according to a Data Management Plan. There are three levels of data checking and quality control: at data entry using restricted value set or compulsory fields, at country level data management running weekly checks and at central level data management with a monthly consistency data check. The collected data is anonymized by the use of unique study identification numbers and followed by the investigators through a dashboard system developed at central level. The tablets used for the study are password-protected and have an individual identification for each research assistant. The tablet data is encrypted when sent to the server. The study database is on a web-based platform provided by REDCap(40, 41), protected by password, encrypted and hosted at the Institut de Recherche pour le Development in Montpellier, France. The back-up of the database is done on a daily basis on the server of the Institut de Recherche pour le Development in Montpellier.
Quality management
Each country research team is composed of one study coordinator, one clinical research assistant and 8 research assistants. All staff is trained on good clinical practices, protocol and study standard operating procedures. Training of the country research teams took place before the baseline phase and was done by the central research team. CHW were selected based on criteria regarding their education, experience with community activities, and acceptability by the community and capacity for study activities. The site teams (TB focal person, TB nurse, CHW and safety monitor) were trained before the intervention phase by the country research teams. Each facility cluster has a clinician safety monitor trained to consult children with tolerability complaints and report adverse events. Standard operating procedures, country-specific manuals of procedures (to take into account the implementation specificities of each country) and a quality management plan were developed by the central research team. Clinical research assistants perform internal data monitoring from the eCRF against source documents on a monthly basis and central site monitoring is done every 3–4 months. In addition, the sponsor performs a yearly site monitoring.
The study is overseen by a steering committee involving all investigators including representatives of the national TB program with monthly calls to discuss study inclusions, challenges and decisions on study implementation and a scientific advisory committee composed by experts in the field of pediatric tuberculosis and randomized controlled trials with meeting twice a year to discuss study progress, challenges and safety review. A country community advisory board is constituted to give guidance on the implementation of the community activities and support the study team on patient information and communication.
Statistical analysis
Primary analysis
The denominator for the analysis of the primary endpoint is the number of child contacts < 5 years and HIV-infected 5–14 years declared by the index case at the facility during the inclusion visit. Since discrepancies can be expected between what is declared by the index case and what is observed during contact screening, a sensitivity analysis will be performed using as denominator the number of children < 5 years of age and HIV-infected children of 5–14 years of age identified during the screening.
A mixed model will be used to perform individual level analysis adjusting for clustering. The regression model will include two random-effects, one for the cluster and one for the household. A degree-of-freedom correction will be applied (Satterthwaite method) to deal with the type I error inflation due to the small number of clusters. The primary analysis will focus on the difference between the two study arms adjusted for country and a secondary analysis will add an adjustment for unbalanced factors (urban/rural, district size) identified in the baseline assessment. For the analysis of the secondary outcomes, a similar mixed model will be used with the same random effects and correction method, focusing on each endpoint of the cascade of care for initiation and completion of TPT and each endpoint of the cascade of care for TB detection.
The proportion of children notified in the facility TPT register among all notified cases during the intervention period will be compared between the two models of care and will also be compared with the same proportions before intervention for the same time period (data collected during the baseline assessment). The proportion of confirmed TB among all pediatric notified cases and the proportion of treatment completion will also be compared between the two models and with the pre-intervention period.
Qualitative assessment analysis
All transcripts from the in-depth interviews and focus group discussions are transcribed in French if the activity was conducted in French and in English if the activity was conducted in local language or English. For the analysis, an interim analysis process will be used. Major themes from the interviews and focus groups will be listed according to the objectives of the study before starting the analyses (a priori codes) and will be enriched if other themes will be found to be relevant to the study objectives (inductive codes). The analysis will be done using the software ATLAS.ti 8 2017.
Cost effectiveness analysis
The two models of care will be analyzed and their cost-effectiveness in each country assessed.
The analysis will be from the health care system’s and the primary analysis will generate an incremental cost per Disability-Adjusted Life Year averted for the intervention model of care vs the standard of care, with a mathematical model used to extrapolate effects observed in the trial to a lifetime time horizon. Additional analyses will include reporting of patient costs incurred during illness and care-seeking, and an asset-based wealth quintile of participants, and generation of additional measures of health impact (deaths and TB cases averted).
Ethical aspects
Protocol approval
The study protocol has been submitted and approved by two central IRBs: Advarra IRB from the United States of America, which is the sponsor’s institutional IRB and WHO Ethics Research Committee. In addition, the protocol was submitted and approved by the local IRBs: Cameroon National Ethics Committee for Human Health Research and Research Ethics Committee of the Mbarara University of Science and Technology in Uganda. In Cameroon it has also been approved by the Direction for Operational Research from the Ministry of Health and in Uganda by the Ugandan National Council for Science and Technology.
Informed consent
All consent forms used for the CONTACT study have previously been approved by the central and local ethics committees. Written informed consent is obtained from index cases and contacts, who are informed of the study objectives, procedures and their risks and benefits. In addition, children older than 7 years in Cameroon and 8 years in Uganda provide written informed assent. Participants with incapacity consent through their legal representative and illiterate participants consent through a witness who is not part of study staff. Country-specific informed consent forms are developed to allow for different standard of care specificities. For index cases, the TB focal person collects the informed consent at the inclusion visit. For contacts in the facility-based model the TB focal person, assisted by the research assistant, collects the informed consent. In the community-based model, only the research assistant can collect the informed consent.
Individual consent is obtained by the researchers during qualitative activities: focus group discussions and in-depth interviews and also during the patient cost collection for the cost-effectiveness analysis.
Handling withdrawals
At any moment a contact case can withdraw their consent without any consequence for their care and their data prior to the date of withdrawal are kept for analysis. Their case management continues under the NTP guidelines.
Confidentiality
Each participant has a unique study code. No directly identifying data is entered into the database. An identification log allows the research assistants to make the link between the code and the name if needed and this log is kept separately in locked study cabinets on site.