A Five Years Tuberculosis Treatment Outcome at Kolla Diba Health Center, Dembia District, Northwest Ethiopia: A Retrospective Cross-sectional Analysis

Background: Multiple studies of tuberculosis treatment have indicated that effective treatment of tuberculosis requires adherence to a minimum of 6 months treatment with multiple drugs. At Kolla Diba Health Center, standardized tuberculosis prevention and control programme, integrating Directly Observed Treatment, Short Course (DOTS) strategy started in 1996. Treatment outcome is an important indicator of tuberculosis control programs as the World Health Organization suggested. We, therefore, carried out this study to investigate the outcome of tuberculosis treatment at Kolla Diba Health Center, Dembia District in Northwest Ethiopia. Methods: A five years records of 827 tuberculosis patients at Kolla Diba Health Center was analyzed to assess tuberculosis treatment outcomes. Bivariate analyses using logistic regression model was used to analyze the association between treatment outcome and potential predictor variables. Results: There were 827 (403 males, 424 females) with mean (SD) age of 31.1 (16.9) years study participants. Tuberculosis type was categorized as smear positive, 169 (20.4%), smear negative 278 (33.6%) and extrapulmonary case, 380 (45.9%). Treatment outcome was classified as successfully treated, 708 (85.6%), defaulted, 29 (3.5%), transferred out, 63 (7.6%) and died, 27 (3.3%). Patients aged 15 years or less had significantly high treatment success rate (aOR 4.576, P=0.004) followed by 35-44 years (aOR 3.829, P=0.003) and 25-34 years (aOR 3.669, P=0.002). Ninety (10.9%) patients were co-infected with HIV, which had more likely to die or transferred out compared to uninfected cases. Conclusion: Treatment success rate was fairly satisfactory. A high proportion of patients died or transferred out in HIV co-infected tuberculosis patients which is a serious public health concern that needs to be addressed right away.


Introduction
Tuberculosis (TB) is one of the leading causes of death worldwide, and it kills around 1.7 million people each year [1]. Effective treatment of TB requires adherence to a minimum of 6 months treatment with multiple drugs [2,3]. In 1995, World Health Organization (WHO) set up Directly Observed Treatment, Short-course (DOTS) strategy.
It involves provision of standard courses of anti-tuberculosis drugs to patients under trained observers to prevent people from failing to complete their treatment. WHO has set a target level of 85% treatment success. People do often have problems sticking to treatment with unclear reasons. However, factors like access to and a person's social and financial situation might affect adherence to their treatment [1,3]. Ethiopia stands 7 th among world's top 22 TB high-burden countries, with an estimated annual incidence of 250 TB cases/10 5 populations [2][3][4][5][6][7][8]. As in many other resource-constrained settings, treatment outcomes have not been satisfactory, mainly due to poor treatment compliance [4] and low coverage of short course chemotherapy in North West Ethiopia. Delays in diagnosis and treatment initiation, devastating HIV/AIDS epidemic and potential threat of anti-tuberculosis drug resistance represent serious threats to TB control effort in the region [9]. HIV co-infection among TB patients in the region is also high (52.1%) [9].
Treatment of TB aims at curing patients, interrupting transmission and preventing emerging of drug resistant bacilli [10]; however, these are not achieved in many regions of the world. Possible reasons are death of patients during treatment, default or resistance of bacilli to the drugs prescribed [11]. Treatment outcomes indicate quality of TB treatment provided by a health system. Treatment outcomes evaluation using standardized categories has been issued by WHO in conjunction with European Region of the International Union against Tuberculosis and Lung Diseases (IUATLD) [12].
Ideally, treatment outcomes in all patients should be routinely monitored by the epidemiological surveillance system. According to Ministry of Health of Ethiopia, TB is one of the leading causes of morbidity, the fourth cause of hospital admission, and the second cause of hospital death [13]. Tuberculosis contributes to 4.6% of all Ethiopian disability adjusted life years.
Tuberculosis mortality rate is estimated at 84/10 5 populations per year [13]. However, treatment outcome of tuberculosis patients has not yet been assessed in Dembia District, Northwest Ethiopia. Therefore, this study aimed to assess treatment outcomes of TB cases attending Kolla Diba Health Center DOTS Clinic.

Study design and data collection
A record based retrospective analysis of profile and treatment outcomes of all TB patients registered from July 2007 to June 2012 was conducted. Registration documents reviewed contained basic information: patients' age, sex, address, type of tuberculosis, and treatment outcome.

Operational definition
Clinical case and treatment outcome definitions were used according to the standard definitions of NTLCP [14], and WHO guide lines [15]: Smear-positive tuberculosis: A patient with at least two sputum were positive for AFB microscopy, or a patient who has only one sputum was positive for AFB microscopy, and chest radiographic abnormalities consistent with active pulmonary TB.
Smear-negative tuberculosis: Symptomatic illness in a patient with at least two sputum smear examinations negative for AFB on different occasions in whom pulmonary tuberculosis is later confirmed by culture, biopsy, or other investigations.
Treatment outcomes: Treatment outcomes were divided into six categories according to NTLCP guidelines: cured (finished treatment with negative bacteriology result at the end of treatment or sputum smear negative on two occasions at the end of treatment), completed treatment (documented treatment completion, but not sputum smear microscopy available at the end of treatment), defaulted treatment (patients who interrupted their treatment for two consecutive months or more after registration), died (patients who died from any cause during the course of treatment), transferred out (a patient referred to another health facility/clinician for treatment in whom information on treatment outcome cannot be obtained) and successfully treated (a patient who was cured and/or completed treatment, or sum of cases that were cured and completed treatment).
We have used the sample size (n) formula: n=(zβ+zα/2) 2 pq/2 Data were entered, cleared and analyzed using the IBM SPSS Statistics 20 msi. Two individuals were independently cross-checked each entry to ensure quality of data. Association between treatment outcomes and potential predictor variables were analyzed using logistic regression model. P values of less than 0.05 were considered statistically significance.  Table 2

Discussion
Tuberculosis has long been recognized as a major public health problem since the 1950s. Since then control efforts have been initiated by the establishment of Sanatoria and later strengthened by implementation of DOTS strategy in the 1990s. However, TB fuelled by HIV/AIDS epidemic, still remains a major health problem in Ethiopia and other developing countries [13]. WHO 2005 report on global tuberculosis control [17] showed that treatment success rates under DOTS programs among 22 high-burden countries varied from 60% in Uganda to 93% in China, with an average of 83%. Besides this, the study in Southern Ethiopia revealed that treatment success rate of all TB cases was 49% [18]. Our study, however, found that treatment outcome of TB patients treated under DOTS program at Kolla Dibab Health Center was satisfactory ( Table 2). This is in line with nationwide success rate in Ethiopia (85%) [14], a surveillance and outbreak report conducted in three European countries (85%) [19], and WHO 2005 report on global TB control (83%) [17]. On the contrary, our finding is higher than what had previously been reported in Ethiopia (29.5%) [6] and (46.8%-68.7%) [20], European countries (69%) [21], Switzerland (70%) [22], in Brazil (75.9%) [23] and Spain (82%) [24]; however, it is   lower than reports in California (97.8%) and WHO target success rate in developing settings (90%) [3]. This fairly satisfactory treatment success rate observed in this study might be due to low transfer, default and death rates ( Table  2), as compared to other study where transferred, default and death rates were 42%, 18.3%, and 10.1% [6], respectively. Our findings are a testament to (1) the valuable contribution of extension health workers in combating control of diseases, mounting of public awareness on infectious diseases, and expansion of health institutions and (2) an increase in qualified health professionals in underserved areas of the country.
Default rate (Table 2) in this study was lower than average default rate (6.2%) among the 22 high burden countries [17] and in different studies carried out in Ethiopia (10%) [16], (20%) [1], (18.3%) [6], (18.6%) [18], (12.5%-40.6%) [20], Malawi (11.5%) [25], Spain (5%) [24], Brazil (20.9%) [23] and Nigeria (17%) [25]. On top of this, default rates decreased across years from 13(8.7%) in (July 2008-June 2009) to 1 (0.7%) in (July 2011-June 2012) ( Table 2) which is different from a report in Ethiopia [6]. Low default rate in our study might be because of the valuable effect of DOTS, increasing of patients' awareness on infectious diseases and expansions of health institutions in the country which can alleviate the effects of distance on treatment outcomes. It was illustrated in a study in Ethiopia which depicted that apparent clinical improvement after intensive treatment phase was the commonest reason for defaulting followed by far distance of the health institution [16]. It is also explained by the fact that studies done in different parts of the world showed patients who completed their treatment had a better understanding of the duration of TB treatment than patients who interrupted their treatment [26,27]. Satisfaction with the health provider had also positive contribution to the continuation of drug intake [27]. The qualitative study in Ethiopia also demonstrated remarkable changes in patients' understanding of TB that treatment completion rate was significantly better in TB club group (68.7%) than (46.8%) comparison group. The defaulter rate was also significantly lower in TB club group (12.5%) compared to (40.6%) comparison group [20]. Thus, enhanced supervision and monitoring, improved counseling during intensive and continuation phases of treatment, home visits, defaulter tracing and health education are useful to reduce TB treatment interruption.
Total death rate found in our study is higher than reports from Ethiopia (2.6%) [18] (Table 2) and Brazil (1.7%) [23], but is lower than other studies carried out in Ethiopia (10.1% [6], Europe (9%) [21], Switzerland (14%) [22] and Brazil (6.4%) [28]. Our study also demonstrated that death rate of TB patients was considerably increased with age from 1.0% in age group of 25-34 years to 9.1% in 55-64 years (Table 3). This is in conformity with findings of studies conducted elsewhere in the world [6,29]. However, data related to treatment failure were not available in this study. Various previous report indicated that increasing age to be a risk factor for death due to increasing co-morbidities and physiological deterioration with age and thus, close scrutinizing of treatment in older patients is indispensable [21,30]. In addition, MDR-TB (Multi Drug Resistant-Tuberculosis) might have contribution for the death of patients since data from DST survey conducted in Ethiopia between 2003 and 2006 shows that levels of MDR-TB are: 1.6% and 11.8% in new cases and retreatment cases of TB patients, respectively [13]. Increasing adherence and improving in the elderly should also be a priority [4].
Earlier study in Ethiopia showed that high proportions (52.1%) of TB patients were co-infected with HIV [9]. This report is higher than our finding (Tables 1-3). Of which, majority cases were smear negative pulmonary TB (42.2%) and EPTB (42.2%) ( Table 5). High fatality rate was seen in those TB patients co-infected with HIV; however, it is slightly lower (15.5%) than a statement from Nigeria [25] (Table 3).
In our study, the number of EPTB cases remained highest compared to smear positive and smear negative TB cases over the years (Table 2). However, it is inconsistency with a finding in Ethiopia where smear negative TB cases the lead [6]. As literatures explained, EPTB has been becoming more common in the era of HIV [14] which supports our finding. Highest treatment success rate was observed among EPTB patients compared to smear positive and smear negative pulmonary TB patients (Table 4). In summary, treatment success rate of pulmonary and EPTB patients treated under the DOTS program at Kolla Diba health center in northwest Ethiopia was acceptably good. Relatively high proportion of patients died or transferred out in those TB patients co-infected with HIV which is a serious community health alarm that needs to be addressed without delay. To improve treatment outcomes of TB patients mainly, in HIV/TB co-infected, we recommend enhanced supervision and monitoring, improved counselling during the intensive and continuation phases of treatment, home visits, early screening and starting antiretroviral drugs and health education to diminish treatment break.