Study setting, diagnostic criteria and treatment regimen
The study was conducted in all the five main prisons (Bauchi, Azare, Ningi, Misau and Jama’are) in Bauchi State. The prisons housed both male and female inmates and lock-up above its maximum capacity and the holding cells are usually overcrowded. The maximum capacity of Bauchi prison is 500, Azare 320, Misau 120, Ningi 110 and Jama’are 151. At the time of the study the total inmates’ population was 2106 out of this figure, eleven were females. Bauchi prison had 1006 inmates, Azare 501, Misau 204, Ningi 159 and Jama’are 236. The prisons have clinics with various cadre of healthcare workers (Doctor, nurses, community health officers, pharmacy assistant, dental assistant, community health extension workers, laboratory technologists and radiographer) that provides mainly curative services for inmates, staff and staff relations. These prisons clinic were poorly equipped with no Gene Xpert, sputum microscopy or drug susceptibility testing services. TB diagnosis in these prisons relied mainly on referral of inmates with presumptive TB to public health facilities outside the prisons. Bauchi prison refer to State specialist hospital, Bauchi; Azare prison to federal medical center, Azare; Ningi, Jama’are and Misau prisons refer to Ningi, Jama’are and Misau general hospital respectively. Presumptive TB case is an inmate with cough of ≥ 2 weeks with at least one of the following symptoms; fever, night sweats, shortness of breath, chest pain, haemoptysis and or unintentional weight loss. The diagnosis was carried out at the referral hospitals using Gene X-pert MTB/RIF rapid diagnostic test or the direct smear microscopy and/or chest X-ray, and histopathological investigation. A presumptive TB case positive for Gene X-pert, or with at least two sputum smear positive for AFB (Acid Fast Bacilli) by direct smear microscopy or one sputum smear positive for AFB with radiological abnormalities consistent with active pulmonary TB is considered as a smear positive TB case. A presumptive TB case negative for Gene X-pert, or all three sputum samples negative for AFB by direct smear microscopy and with radiological abnormalities consistent with pulmonary TB is considered as a smear negative TB case. An inmate with TB of other organs outside the lungs as detected by tissue biopsy or based on strong clinical evidence consistent with active extra-pulmonary TB.
Prison inmates diagnosed of TB by the public health facilities are placed on Anti-TB drugs for the full course depending on the treatment category but continued the treatment in the prisons under the supervision of the TB desk officers, who also kept the TB treatment cards. Inmates diagnosed with TB are kept in isolation cells within the prisons during the intensive phase of treatment and the drugs are administered through the DOTS strategy. The treatment is based on new or retreatment TB cases; new cases (treatment category 1) received 6 months treatment regimen of two months of intensive phase of combination of four drugs (Rifampicin, Isoniazid, Pyrazinamide and Ethambutol) and four months of continuation phase of two drugs (Rifampicin and Isoniazid) while previously treated cases (category 2) received 8 months regimen consisting of two months treatment with Streptomycin, Rifampicin, Isoniazid, Pyrazinamide and Ethambutol followed by a month treatment of Rifampicin, Isoniazid Pyrazinamide and Ethambutol during the intensive phase followed by five months continuation phase with Rifampicin, Isoniazid and Ethambutol. The dosage of the drugs depends on the patient’s pre-treatment weight. Follow-up bacteriological test is done during treatment at the end of second, fifth and sixth months for all new sputum smear positive cases and at the end of the third, fifth and eight months of treatment for previously treated sputum smear positive cases. Weight follow-up measurements are done at the end of the second, fifth and at the end of the last month of treatment. Inmates on Anti-TB are not allowed to be transferred to other prisons but those discharged from prisons are given transfer form by the desk officer to the nearest DOTS center to the inmate’s residence. These inmates are not followed up to know if they actually reported to the DOTS center or continued the treatment. All presumptive TB cases are counselled and tested for HIV using determine (rapid HIV test kit), positive cases were confirmed with Stat-Pak (rapid HIV diagnostic kits), while Uni-Gold recombinant assay is used as tie-breaker for discordant results.
Study design and population
We conducted a review of the treatment outcomes of all prison inmates treated for TB from January 2014 to December 2018 in all five prisons in Bauchi State. All prison inmates treated for TB with Anti-TB drugs from January 2014 to December 2018 were included. Inmates with missing variable(s) of interest in the TB treatment register were excluded (Figure 1).
Data tool and collection
The data source was the TB treatment register and patient health records in the five selected prisons. Data were extracted using a structured checklist. The checklist collected information on age, pretreatment weight, duration of imprisonment, TB class (Smear Positive Pulmonary Tuberculosis [SPPTB], Smear Negative Pulmonary Tuberculosis [SNPTB], Extra-Pulmonary Tuberculosis [EPTB]), treatment category (New, Retreatment, Unknown), HIV status, treatment outcomes (cured, treatment completed, failure, lost to follow-up, transferred out and died), from the TB treatment registers in the various study prisons by five trained healthcare workers (HCWs). The five HCWs (one from each prison) were trained for a day on how to collect the data and use the checklist. The principal researcher daily reviewed the filled format and strictly supervised the trained research assistants. Data were collected over a period of five weeks. Each prison was assigned a week; this enable the researcher to supervised the process of data abstraction.
Measurement
The dependent variable (treatment outcome) was dichotomized as successful (cured and treatment completed) and unsuccessful (treatment failure, lost to follow-up, transferred out and died) and the independent variables were socio-demographic characteristics (age, weight, duration of incarceration) and clinical characteristics (HIV status, TB class and treatment history). The following operational definitions were adopted from WHO for drug-susceptible TB.21
Cured: A PTB case with bacteriologically confirmed TB at the beginning of treatment who was smear or culture negative in the last month of treatment and on at least one previous occasion.
Treatment completed: A TB case who completed treatment without evidence of failure but without records to show that sputum smear or culture results in the last month of treatment and on at least one previous occasion were negative, either because tests were not done, or results were unavailable.
Treatment failure: A TB case whose sputum smear or culture is positive at month 5 or later during treatment.
Lost to follow-up: A TB case who did not start treatment or whose treatment was interrupted for two consecutive months or more.
Not evaluated: A TB case for whom no treatment outcome is assigned. This includes cases transferred out to another treatment unit as well as cases for whom the treatment outcome is unknown to the reporting unit.
Died: A TB case who dies for any reason during treatment.
New TB patient: A TB case who has not previously been treated for TB and is now diagnosed and has started the current treatment.
Relapse/Retreatment: A TB case who was previously treated for TB and was declared cured and now diagnosed and started the current treatment.
Data analysis
Extracted data were checked for its completeness, correctness and analyzed using Epi-info software version 7.2.2.6. Descriptive statistics was used to generate summary frequencies, percentages, and means. Bivariate analysis was performed to measure association between treatment outcome and independent variables. Covariates with p-value of ≤ 0.2 in the bivariate analysis were included in the multiple logistic regression model to identify predictors of treatment outcomes at 95% confidence intervals (CIs).
Ethical consideration
Ethical approval was obtained from the Bauchi State Health Research Ethics Committee. Permission was sought and obtained from the Controller of Prisons, Bauchi State command, where the aim and objectives of the study were explained. The information obtained was made anonymous and de-identified prior to analysis to ensure confidentiality.