Tuberculosis and the determinants of treatment outcome in Zaria, North Western Nigeria – A nine-year (2007–2015) epidemiological review

Introduction: Tuberculosis (TB) kills, worldwide, about 1.5 million people infected by the disease per year according to the 2015 World Health Organization (WHO) Global TB report. In sub-Saharan Africa, Nigeria accounts for the highest absolute number of TB morbidity and the 4th among the six high-TB burden countries, which account for about 60% of all TB cases globally. Materials and Methods: This study is a retrospective, descriptive cross-sectional review of the facility TB registers of 4054 patients who accessed TB healthcare services at the 25 directly observed treatment short course (DOTS) Primary Health Care facilities in Zaria, Northwestern Nigeria, between January 1, 2007 and December 31, 2015. Results: Majority of the patients were males (2601; 64.2%), belonging to the age group <40 years (2837; 70%) The patients presented mainly with pulmonary TB (3591; 88.6%). Only half the number of patients (50.3%) had smear-positive results before the commencement of short-course chemotherapy with either 2RHZE/6EH or 2SRHZE/IRHZE/5RHE (1, 2 = 1 or 2 months intensive phase, 5 = 5 months continuation phase, R = rifampicin, H = isoniazid, Z= pyrazinamide, E = ethambutol, S = streptomycin). Human immunodeficiency virus (HIV) coinfection was reported in 774 (19.1%) patients. The treatment success rate was 80.2% (3253 patients); 278 (6.9%) of the patients were lost to follow-up, 176 (4.3%) were transferred out, and 235 (5.8%) died. The determinants of the unsuccessful treatment outcome were being a male, aged >40 years, TB and HIV coinfection, a greater degree of sputum smear positivity before treatment, located at far distances from DOTS centers, and being on retreatment or second-line regimen. Conclusion: The treatment success rate falls below the recommended 85% by the WHO. Recommendations: There is a need for the Nigeria government in collaboration with international agencies to intensify effort at TB surveillance, monitoring, and control activities in Nigeria. Effort should be directed at promoting TB/HIV awareness, the early recognition and diagnosis of TB, and strategies to expand and improve DOTS service at community level.