Treatment Outcome of Tuberculosis Patients at Enfraz Health Center, Northwest Ethiopia: A Five-Year Retrospective Study

Objectives. The aim of this study was to assess treatment outcome and associated risk factors among TB patients registered for anti-TB treatment at Enfraz health center, northwest Ethiopia. Methods. A five-year retrospective data (2007–2011) of tuberculosis patients (n = 417) registered for anti-TB treatment at Enfraz health center, northwest Ethiopia, were reviewed. Tuberculosis outcomes were following the WHO guidelines. Data were entered and analyzed using SPSS version 20. Results. Among 417 study participants, 95 (22.8%), 141 (33.8%), and 181 (43.4%) were smear-positive, smear-negative, and extrapulmonary tuberculosis patients, respectively. Of the 417 study participants, 206 (49.4%) were tested for HIV. The TB-HIV coinfection was 24/206 (11.7%). Seventeen study participants (4.2%) were transferred to other health facilities. Among the 400 study participants, 379 (94.8%) had successful treatment outcome (302 treatment completed and 77 cured). The overall death, default, and failure rates were 3.4%, 0.5%, and 1.2%, respectively. There was no significant association between sex, age, residence, type of TB, HIV status, and successful TB treatment outcome. Conclusion. Treatment outcome of patients who attended their anti-TB treatment at Enfraz health center was successful. Therefore, this treatment success rate should be maintained and strengthened to achieve the millennium development goal.


Background
Tuberculosis (TB) is a major global health problem. It causes illness among millions of people each year and ranks as the second leading cause of death from an infectious disease worldwide, next to HIV infection. According to the World Health Organization (WHO) 2012 report, almost 9 million new cases and 1.4 million TB deaths occur worldwide by the year 2011 [1]. These deaths occurred in the presence of treatments that were able to cure most of the cases.
Geographically, the burden of TB is the highest in Asia and Africa. The African region has 24% of the world's cases and the highest rates of cases and deaths per capita [1]. Almost 80% of TB cases among people living with HIV reside in Africa [1]. Among 22 high burden countries (HBCs) of TB, Ethiopia ranks the 7th with an estimated prevalence of 394/100,000 population [1].
According to the Ethiopian Ministry of Health report, TB is the leading cause of morbidity, the third leading cause of hospital admission, and the second cause of death in Ethiopia [2]. Recording and reporting the number of cases detected by national TB control programmes (NTPs) and the outcomes of treatment are of the five component packages of the directly observed therapy short-course strategy (DOTS) [1]. In 1992 Ethiopia has started the implementation of DOTS within the standardized TB prevention and control program [2]. Currently DOTS coverage is estimated at 100% geographical and 95% health facility level [1].
Despite high DOTS coverage in northwest Ethiopia, the treatment outcome of TB patients in health centers has not been assessed so far. There is little information about factors responsible for unsuccessful treatment outcome in the region. In this study, we assessed the treatment outcomes of TB patients in DOTS program and associated risk factors with unsuccessful TB treatment outcome in Enfraz health center, northwest Ethiopia.

Study Area.
Enfraz health center is located in the northwest part of Ethiopia. Enfraz is a historic town 678 Kilometers away from Addis Ababa, capital city of Ethiopia. The health center is the only facility that renders DOTS service for the people living in and around Enfraz. Patients were diagnosed, registered, treated, and referred to other DOTS clinics following the National Tuberculosis and Leprosy Control Program (NTLCP) guideline [2].

Study Design and Data Collection.
A retrospective study was conducted among TB patients registered from 2007 to 2011 at DOTS clinic. The sociodemographic data (such as sex, age, and residence), category of TB at the start, and the treatment outcomes of the TB patients were collected from the DOTS registration book.

Definitions.
The Ethiopian NTLCP guideline [2], adopted from WHO, was used for the following clinical case and treatment outcome definitions.

Smear-Positive Pulmonary TB Case.
Smear-positive pulmonary TB is the case of a patient with one or more initial sputum smear examinations (direct smear microscopy) AFB-positive or one sputum examination AFB-positive plus radiographic abnormalities consistent with active pulmonary TB as determined by a clinician.

Smear-Negative
Pulmonary TB Case. Smear-negative pulmonary TB is the case of a patient with pulmonary TB who does not meet the above criteria for smear-positive disease. Diagnostic criteria should include the following: at least two AFB-negative sputum smear examinations; radiographic abnormalities consistent with active pulmonary TB; no response to a course of broad-spectrum antibiotics (except in a patient for whom there is laboratory confirmation or strong clinical evidence of HIV infection); and a decision by a clinician to treat the patient with a full course of anti-TB chemotherapy. A patient with positive culture but AFBnegative sputum examinations is also a smear-negative case of pulmonary TB.

Extrapulmonary TB Case.
Extrapulmonary TB is the case of a patient with TB of organs other than the lungs (e.g., pleura, lymph nodes, abdomen, genitourinary tract, skin, joints and bones, and meninges). Diagnosis should be based on one culture-positive specimen or histological or strong clinical evidence consistent with active extrapulmonary disease, followed by a decision by a clinician to treat a patient with a full course of anti-TB chemotherapy. A patient in whom both pulmonary and extrapulmonary TB has been diagnosed should be classified as a pulmonary case.

Treatment
Outcome. Cured: a patient who was initially sputum smear-positive and who was sputum smear-negative in the last month of treatment and on at least one previous occasion. Completedtreatment: when a patient completed treatment but did not meet the criteria for cure or failure. This definition applies to sputum smear-positive and sputum smear-negative patients with pulmonary TB and to patients with extrapulmonary disease. Died: when a patient died from any cause during treatment. Failed: when a patient was initially sputum smear-positive and when a patient remained sputum smear-positive at month 5 or later during treatment. Defaulted: when a patient whose treatment was interrupted for 2 consecutive months or more. Successfully treated: when a patient was cured or completed treatment.

Statistical
Analysis. Data were entered, cleaned, and analyzed using SPSS version 20 statistical software. Data were entered into a computer and analyzed twice by two independent investigators to ensure their quality. Bivariate and multivariate analysis were done to analyze whether there is association between the TB treatment outcomes and independent variables. Crude and adjusted odd ratio were computed and used to see the strength of association. values less than 0.05 were considered statistically significant.

Ethical Considerations.
Institutional ethical clearance was obtained from the college of Medicine and Health Sciences research ethical committee of University of Gondar.

Characteristics of Study Participants.
A total of 417 TB patients whose age ranged from 0.17 to 80 years, mean and standard deviation of 31.91 ± 1.69 years, were included in the study. Among 417 study participants 108 (52.3%) were females and 199 (47.7%) were males. Children ≤ 14 years accounted for 14.6% of the study participants. Majority of the patients were rural residents (270 (64.7%)) ( Table 1).

Treatment Outcome.
The treatment outcome of most study participants was successful (302 completed their anti-TB treatment and 77 cured). The treatment failure, defaulter, and death rates were 0.5%, 1.2%, and 3.4%, respectively ( Table 2).
Since the status of 17 TB patients (transferred out cases) is not known we excluded them from the treatment success rate analysis. The overall five-year treatment success rate of the TB patients was 94.8% (379/400).
The provider initiated HIV counseling and testing In the bivariate analysis, age between 35 and 44 years and ≥65 years showed statistically significant association with unsuccessful treatment outcome as compared to patients aged between 15 and 24 years. The multiple logistic regression showed no significant association between unsuccessful treatment outcome and the different characteristics of the TB patients including age, sex, residence, and HIV status ( > 0.05 in all cases) ( Table 3).
In this study, in the first three years (2007-2009) smearpositive pulmonary TB was the leading type of TB (ranged from 17.9% to 27.4%), while the last two years showed an increment in smear-negative pulmonary TB cases (ranged from 20.6% to 25.5%
In the present study, the prevalence of HIV among TB patients was 11.7%. This was comparable from different parts of Ethiopia such as Nekemte 11.5% [11], West Arsi 13.6% [6], and Dembia with 10.9% [13]. However, the present study TB-HIV coinfection was lower than previous reports from different health centers at Addis Ababa, Gondar University Hospital, and Felege Hiwot Referral Hospital, 27.2% [18], 52.1% [19], and 25% [12], respectively. TB-HIV coinfection in present study (11.7%) was also lower than in the WHO estimate (39%) in Africa [1]. The lowered TB-HIV coinfection in this study might be due to the higher number of rural study participants than urban residents (64.7% versus 35.5%) ( Table 1).
Fourteen (3.4%) study participants died during their course of their treatment. This report was consistent with reports from Kolladiba Health Center (3.3%) [13] and different health centers in Addis Ababa (3.7%) [16] and Tigray (3.9%) [8]. The death rate of this study was lower than reports from Gondar University Hospital [5], Felege Hiwot Referral Hospital [12], and Gambo Rural Hospital [6], 10.1%, 5.8%, and 5.3%, respectively. The lower death rates in the present study might be due to the difference in the study sites, by which the study was done in rural health center, while the higher death rates in hospitals might be due to hospitalization of more critical TB patients in hospitals than in health centers. Health professionals working in DOTS clinic of the health centers  might reach and advise TB patients who discontinue their anti-TB treatment than hospital workers due to their smaller catchment area and less work load. This work in turn might lead to a decrease in death rate. The other reason for low death rate in the present study might be due to the lower TB-HIV co-infection (11.7%) as compared to previous studies done at Felege Hiwot Referral Hospital (25%) [12] and Gambo Rural Hospital (13.6%) [6]. The TB treatment failure rate of this study was 0.5%, which was lower than the average TB treatment failure rate of the 22 HBCs [20]. Failure rates that ranged from 0.2% to 18.6% were reported from the different parts of Ethiopia [5][6][7][8]12].
In this study, in the first three years (2007-2009) smearpositive pulmonary TB was the leading type of TB (ranged from 17.9% to 27.4%), while the last two years showed an increment in smear-negative pulmonary TB cases (ranged from 20.6% to 25.5%). This might be due to the increase in the HIV prevalence in the health center from year to year (11.1% in 2009 to 16.4% in 2011).
There was no significant association between unsuccessful treatment outcome and the different characteristics of the TB patients in the present study. Similar finding was reported by Datiko and Lindtjørn [17] in Southern part of Ethiopia. This result might be due to the poor characteristics of the retrospective study design to identify possible risk factors.

Conclusions
This study shows that treatment outcome of patients that attended their anti-TB treatment at Enfraz health center was successful. Enfraz health center has met the target success rate set by WHO. There was no associated risk factor identified for unsuccessful treatment outcome. Therefore, this treatment success rate should be maintained and strengthened to achieve the development goal. Further studies are needed to identify possible risk factors for unsuccessful treatment outcome.