Tuberculosis in the military: Trends in notification and treatment outcomes within the Zimbabwe Defence Forces, Dependants and Communities 2010-2015

Background Historically, tuberculosis (TB) has been responsible for significant disease burden among the military both during peace and conflict. A routine review of Zimbabwe Defence Force (ZDF) data showed 36% of reported deaths could be attributed to TB. We conducted a study to determine the TB trends and outcomes among patients managed in ZDF health facilities between 2010-2015. Methods Retrospective cohort study of TB patients (military and dependents). Data were extracted from ZDF TB registers and analyzed for trends in notification and outcomes. Independent factors associated with unfavourable TB treatment outcomes were modeled using multivariable regression. Results Of the total 1298 TB patients, 84% were males, median age 37 years and 92% from Army facilities. Ninety three percentage had pulmonary TB, 87% were new patients and 68% HIV co-infected (97% on antiretroviral therapy[ART]). Number of TB cases reduced two-fold between 2010-2015 (317 vs 115). Treatment outcomes remained relatively stable with overall treatment success of 81%, 9.9% deaths, 0.2% loss to follow up, 2.2% treatment failure, 6.6% not evaluated. Clients who were HIV-positive and not on ART were 3.81 times likely to have unfavourable outcome. Conclusion This is the first study of TB in an African defence force showed decreasing trends in notified TB cases. Though treatment success was comparable over time, it still fell below international targets. Being HIV-positive (even with ART) was associated with increased unfavourable outcomes. Continued monitoring, evaluation and increased support of the TB programme within this high risk population is recommended.


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Tuberculosis (TB) has become the leading infectious cause of death in Africa and a major global health 50 problem(1). In 2016, there were an estimated 10.4 million TB cases globally, 10% of these among people living 51 with HIV (PLWHIV), and 25% in the African region(2). The number of TB deaths is unacceptably high, but with 52 timely diagnosis and treatment, almost all with TB can be cured The disease led to approximately 1.7 million 53 deaths in the same year (1). The global plan to end TB introduced three people-centred targets called the 90-(90)-54 90 targets: reach 90% of all people who need TB treatment, including 90% of people in key populations, and 55 achieve at least 90% treatment success(2).

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The Sustainable Development Goals (SDGs) for 2030 were adopted by the United Nations in 2015 and a key 58 target is to end the global TB epidemic(3). The WHO End TB Strategy, approved by the World Health Assembly 59 in 2014, calls for a 90% reduction in TB deaths and an 80% reduction in the TB incidence rate by 2030(4). 60 Zimbabwe is one of 14 high burden countries for TB, TB/HIV and multidrug-resistant TB (MDR-TB) in the 61 world (5). The focus of the country is to detect all TB cases early, particularly the bacteriologically positive cases, 62 and provide them with effective treatment in a patient centred approach so as to reduce individual short and long 63 term TB morbidity and mortality, stop TB transmission and reduce or eliminate the risk of development of drug 64 resistance (6). In 2015, TB treatment coverage, defined as the number of new and relapse cases that were notified In the ZDF, routine review of 2016 end-of-year data showed that 36% of all reported deaths could be attributed to 85 TB. However, trends in TB notification and treatment outcomes have not yet been evaluated. It is against this 86 background that we carried out a study to determine the frequency of TB notification, clinical characteristics and 87 treatment outcomes among all patients seen in the ZDF health facilities from 2010-2015.

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Study Design: We conducted a cohort study utilizing routinely collected programmatic data.

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General setting: Zimbabwe is a lower middle income country in southern Africa. The country is divided 92 into ten administrative provinces and 62 districts. The capital city is Harare and other major cities include 93 Bulawayo, Gweru, Kadoma, Kwekwe, Masvingo and Mutare. The population of Zimbabwe is estimated to be 16 million with 52% being female (9). The Ministry of Health and Child Care provides health coverage in the 95 country and is essentially free of cost.

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The National Tuberculosis Control Programme: The Zimbabwe National TB Control program 97 (NTP) is responsible for control of TB in the country(9). The goals of the NTP are to find at least 90% of new TB 98 cases, provide care for 90% of new TB patients, decrease mortality due to TB, decrease the challenges placed 99 upon families and communities, and to ultimately eliminate TB(6). The NTP program also oversees TB control in    3. TB services are made available at all levels of the health delivery system and integrated into the primary health    Zimbabwe has established healthcare services countrywide and well developed HIV/TB programs that are 16 supported by collaborative partners. There are more than 100 TB centres nationally and care is provided free of 17 cost at MoHCC facilities(9) . The 2016 Global report indicated that Zimbabwe's TB treatment success rate was 81% and mortality at 7.2% (7).    Total number of notified TB cases reduced more than two-fold between 2010 and 2015 (Figure 1). Treatment 58 outcomes remained relatively unchanged over the six year period (Figure 2) with the overall treatment success 59 being 81.1%. Key adverse outcomes were deaths at 9.9%, loss to follow up at 0.2% and not evaluated at 6.6% 60 (

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This is the first study looking at TB notification and treatment outcomes in a defence force setting from Africa.

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The study established a two-fold reduction in TB notification over the six-year period while the treatment 91 outcomes remained relatively stable. Treatment success rates were comparably high (81%) but mortality rates 92 were also high, one-in-ten of notified cases, contributing to most of the unfavourable treatment outcomes. HIV co-93 infection and lack of ART were significantly associated with unfavourable TB treatment outcome. Those HIV co-94 infected on ART still had close to twice the risk of unfavourable outcome while those not on ART had four-times 95 the risk, as compared to HIV negative TB patients.

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The primary strength of our study was that we reviewed all TB patients notified in both Army and Airforce health 97 facilities within Zimbabwe over six years. However, current TB clinical management documentation does not 98 capture whether patients were military personnel or a dependent, which was a significant limitation. The impact of 99 this lack of classification is likely low, because the majority of patients (>85%) were adult males. Additionally, 00 7% of patients did not have outcome data as they were not evaluated. It is suspected these patients actually 01 transferred out, with care being provided elsewhere, but remains uncertain.

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Another major challenge faced with interpreting our study results is the lack of prevalence data. To better assess Treatment success rates were comparable to the Zimbabwe averages ,but are below the current WHO 09 recommended goal of 90% success (2). These findings imply that the TB program within the ZDF -an at risk 10 population -is at least on par with the country's performance. This is admirable on several levels. evaluation of the TB programme is needed so as to attain higher treatment success rates and reduce deaths associated with TB.