Study design
In 2019, we developed a CB DOT model for DR TB based on patient preferences elicited during a previous study. In the CB DOT model, community health workers were assigned as primary caregivers and received travel vouchers to administer DOTs in patients' homes (14). To assess the effectiveness of this model, we designed a quasi-experimental pre and post-study. It comprised of the observational prospective component (P-arm) which was the intervention group, to which MDR TB patients were enrolled onto CB DOT, and the retrospective component (R-arm) as the comparison group consisting of DR TB patients who received HF DOT.
Prospective arm
A CB DOT intervention developed in an earlier study was assigned to eligible MDR-TB patients consecutively (14). Patients were followed up prospectively until, treatment was completed, outcomes were assigned, or patients were administratively censored.
Retrospective arm
The comparison group was comprised of MDR-TB patients who were on HF DOT, initiated treatment in the previous year, and completed their treatment three months before the commencement of the study. Data for this group was collected retrospectively from the five DR TB treatment health facilities, including patients’ characteristics at MDR-TB treatment initiation and treatment outcomes. The same data collection tool was used for data collection for both the intervention and comparison groups.
Study setting
A multi-site study at five tertiary referral hospitals purposively selected which accounted for at least 80% of MDR cases enrolled in care in the country and were representative of the major regions of Uganda. Arua regional referral hospital (RRH), participated in the initial model development(14) but was not included in the evaluation of the model due to administrative challenges.
Selection of community health workers to support community-based DOT
The use of trained lay providers in the provision of DOT for DR TB patients is recommended by the programmatic management of drug-resistant tuberculosis (PMDT) guidelines in Uganda(9, 15). Previously, with regimens that included injectables, DOT was only recommended for provision by lay providers after the completion of the intensive phase that was characterized by injectables (Kanamycin, Amikacin, or Capreomycin)(15). However, the dawn of all oral medications makes the provision of CB DOT throughout the treatment cycle for MDR TB patients possible(9, 16, 17). We selected lay providers who were; 1) chosen by or acceptable to the patient 2) committed to supporting the patient throughout their treatment 3) able to read and write 4) not an immediate family member(14, 15) 5) able to accompany the patient to the clinic for monthly appointments 6) had previously supported health initiatives at the community level including TB and MDR TB 7) of good standing in the community and 8) living close to the patient and not take him or her more than an hour to reach the patient’s home. We planned that each community health worker (CHW) was to support daily DOT up to a maximum of three DR TB patients if within the same locality for efficiency and ease of administration. CHWs were trained on CB DOT model implementation, their role in supporting the DR TB patient, and DR TB specific training that focused on basic TB, TB classifications, the definition of DR TB, causes of DR TB, clinical presentation, medicines used, associated side effects, and drug storage. Ongoing support was availed to CHWs during monthly routine visits to the tertiary referral hospital.
Roles of CHWs
The roles of the CHWs included; 1) Conduct daily visits to the patient’s home to observe him/her swallowing the drug, 2) Record daily community DOT in the patient follow-up log that was presented at the DR TB treatment initiation facility every month 3) Observe during daily interaction with the patient and record any adverse events reported by the patient, any concerns or actions taken 4) Consult virtually with the site study focal person/ clinician on an ongoing basis on all aspects of care, including liaising with initiating facilities on the management of adverse events, including referrals 5) Remind patients of monthly health facility visits 6) Pick up drugs for MDR-TB patients monthly 7) Ensure safe custody/keeping of drugs in a drug box away from dust at room temprature 8) Provide patient health education and infection prevention and control messages to patients and members of the family about MDR- TB, and 9) Provide adherence counseling.
Selection of study participants
Sample size determination
The total number of DR-TB patients in care in the five health facilities by 2019 was 302 patients. Based on the 2018 /19 Uganda National Tuberculosis and Leprosy Program (NTLP) report, the approximate treatment success rate among MDR-TB patients in Uganda was 75%. Assuming a statistical power of 80%, a two-sided hypothesis test with a 5% significance level (standard normal deviate at 95% confidence, Z = 1.96). The desired sample size to detect a 10% increase in treatment success due to CB DOT to achieve the national target of treatment success of 85% was 185 patients in each arm. The estimatedsample size adjusted using finite population correction because of the limited available numbers of DR patients (18). Sampling proportionate to size was used to determine the number of study participants selected from each of the participating hospitals.
Study inclusion criteria
DR TB patients above 18 years of age on a standard short treatment regimen (sSTR)(15) who had completed the injectable phase of DR TB treatment, or those on an all oral modified STR (mSTR)(6) or, on long all oral regimens(6) at the point of enrolment onto the study, after providing signed informed consent, were willing and able to comply with scheduled visits, treatment plan, laboratory tests, and other procedures relevant to assigning treatment outcomes.
Study exclusion criteria
DR TB patients who are on other individualized regimens that included injectables
Data collection
For the R-arm, retrospective data were extracted from DR-TB registers at the study hospitals using pre-designed data collection tools. For the P-arm, prospective data were collected by research assistants (RAs) using the same tool. Patients received daily visits by the CHWs, who observed medicine ingestion, noted any patient concerns and adverse events, and documented data in a patient log.
Study Variables
The main study outcome was the proportion of patients who registered treatment success (those who were cured or those who completed treatment) among those intiated DR TB treatment. The main comparison groups were DOT models of care, i.e. health facility based DOT (HF DOT) versus community-based DOT (CB DOT).
Other participants’ information collected include; Patient demographics (e.g. age, gender), occupation, high-risk populations, duration of MDR TB treatment and presence of co-infections (e.g. HIV).
Statistical Analysis
Quantitative analyses were conducted using STATA software version 16.1 (StataCorp, College Station, Texas, USA). We described participants’ socio-demographic characteristics for both HF DOT and CB DOT groups using descriptive summaries; frequency and percentages for categorical variables, median and inter-quartile range for count data, i.e. age and duration of MDR-TB treatment.
We use Pearson Chi-square test for categorical variables and Wilcoxon rank-sum test for continuous non-normal variables comparing HF DOT versus CB DOT groups. We used prevalence ratios and 95% confidence intervals to compare treatment success across HF DOT versus CB DOT groups using Poisson regression models with cluster-robust standard errors to account for intra-cluster correlation of participants within a hospital. The analysis was adjusted for participants’ characteristics. Modified Poisson regression was used because it estimates adjusted relative risk or prevalence ratios appropriately when the outcome is common (i.e. prevalence > 10%) compared to logistic regression, and it does not have model convergence challenges unlike log-binomial models(19). Only factors with P < 0.3 at unadjusted models were included in the multivarible model, except CB DOT type, the main comparison variable. Joint P-values using Wald test at unadjusted were used in the selection of variables with more than two categories in the adjusted model. We checked whether the effect of DOT type was modified by other participants’ characteristics, by fitting interactions between DOT type and MDR-TB treatment type, sex, and age groups was carried out.