Factors Contributing to Survival of Multi-drug Resistant Tuberculosis Patients in Yangon Region, Myanmar (2017)

Htet Myet Win Maung, Saw Saw, Cho Cho San, Zaw Myint & Si Thu Aung

Special Issue May 2020

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Multi-drug resistant tuberculosis (MDR-TB) is the tuberculosis (TB) with resistance to at least isoniazid and rifampicin, the two most potent anti-TB drugs and it is also the manmade problem on current TB control strategies. Myanmar is one of the 30 high multi-drug resistant tuberculosis (MDR-TB) burden countries. In Myanmar, prevalence of MDR-TB was 5% among new TB patients and 27.1% among retreatment TB patients according to 3^rd nationwide TB drug resistance survey (2012-2013). The survey also showed that there was the alarming MDR-TB situation in Yangon Region as 11% of new TB patients being MDR-TB, which was more than double the national average. Moreover, Yangon is the most crowded and highest population density region in Myanmar. In addition, about 50% of MDR-TB patients in Myanmar were notified and treated in Yangon Region. Treatment of MDR-TB is challenging and complex and treatment success rate (TSR) is lower than outcome of drug-susceptible TB. Globally, TSR of MDR-TB patients was 54% and largely due to high rate of mortality and lost to follow-up according to Global TB Report (2017).¹ Some studies showed that the survival of MDR-TB patients was associated with age, history of TB treatment, HIV status and receiving anti-retroviral therapy (ART) and sputum smear grading at the time of diagnosis.^{2, 3} In Myanmar, according to routine programme data, the death rate of MDR-TB was the highest among unfavourable outcomes. The study aimed to assess MDR-TB patients’ survival and associated factors in Yangon Region. There was no such kind of study and well- published paper on this particular aspect in Myanmar and the result can be used to improve the treatment care and guideline for the country.

This is a retrospective study using secondary data analysis of routinely collected programme data. MDR-TB patients’ data were extracted from the MDR-TB patient individual database and the original source of data was MDR-TB treatment registers in Yangon regional TB control office. The study population was all MDR patients registered for treatment during 2015 under National Tuberculosis Programme in Yangon Region. Data from the excel sheets was exported into R software (version 3.4.1) for further analysis after data verification and data validation. The association between survival and associated factors was analyzed using chi-square test and variables having p value less than 0.2 in bivariate analysis were included in the cox regression model and Kaplan-Meier survival curves were drawn.

and 17(2%) failure among 1,237 MDR-TB patients in Yangon Region. Among total MDR-TB patients, 138(11%) were HIV- positive co-infected patients and, in those co-infected patients, 109(79%) received antiretroviral therapy (ART) within six months of MDR-TB treatment. The overall survival of MDR-TB patients at the 20^th month was 0.861 (95% CI=0.842, 0.881). MDR-TB patients were categorized as following age groups: <24 years, 24-47 years and >48years. Using the age group <24 years as the reference, the age group 24-47 years and the age group >48 years showed difference in survival and associated with poor survival [HR=3.95 (95% CI=2.10, 7.43)] and[HR=7.97 (95% CI=4.25, 14.96)], respectively. The patients who had history of previous TB treatment (“>2months”) showed difference in survival and associated with poor survival [HR=1.59 (95% CI=1.10, 2.31)] when compared with those whohad history of previous TB treatment (“<2months”). Using HIV-negative patients as the reference, HIV-positive patients with no ART within six months of MDR-TB treatment and patients with unknown HIV status were associated with poor survival [HR=3.60 (95% CI=1.82, 7.11)] and [HR=2.39 (95% CI=1.49, 3.82)],

respectively. Interestingly, the survival of MDRTB-HIV patients who received ART within six months of MDR-TB treatment had the same survival as HIV-negative patients. Other factors such as sex and diagnosed sputum grading were not associated with survival of patients.

The treatment success rate and overall survival of MDR-TB patients in Yangon Region were quite good to compare with global and other countries treatment out-comes. This was due to a result of multiple interventions implemented by the National TB Programme (NTP) such as free diagnosis and treatment service, incentives and nutritional support and directly observed treatment (DOT) service to all MDR-TB patients. In this study, age group, history of previous TB treatment, HIV status and ART were associated with survival of patients(Figure). For age group, it might be related to diabetes mellitus (DM), a common comoriddity associated with both old age and TB.^{2, 3}.

However, the DM status of the patients was not systematically recorded in the database and could not be used in the data analysis. Patients with history of TB treatment have higher chances for drug resistance than no history and so they have poor survival⁴. Regarding the HIV status and receiving ART, HIV-positive patients with no ART within six months of MDR-TB treatment and patients with unknown HIV status had poor survival and this result was consistent with other study.⁵In this study, about 21% of HIV-positive patients did not receive ART within six months of MDR-TB treatment and this issue needs to be addressed immediately as WHO recommends. Moreover, HIV-positive patients in the HIV unknown status group may be missed and the universal HIV testing of all MDR-TB patients is needed. There were strengths in this study such as the large MDR-TB individual data accounting for about 50% of total MDR-TB in the country and diagnosis, treatment and outcome definitions followed WHO recommendation. However, there was some limitations because this study used retrospective secondary data and some important variables were missed, such as body mass index, DM status, TB drug resistance patterns, treatment delays, and follow-up culture results.

In conclusion, although treatment success and overall survival of MDR-TB patients were high, the factors associated with poor survival need to be emphasized. It is important to strengthen the HIV testing among all MDR-TB patients and to start ART treatment as early as possible for all MDR-TB/HIV co-morbid patients.

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