Trend analysis and seasonality of tuberculosis among patients attending Hiwot Fana Specialized University Hospital, Eastern Ethiopia: A retrospective study

Abstract Background : Tuberculosis (TB) is a worldwide public health threats caused by Mycobacterium tuberculosis in which about 10.0 million people globally infected in 2017. It is one of the top 10 leading killer diseases in the developing countries, particularly in Sub-Saharan Africa including Ethiopia. However, limited studies are available on seasonal variation and level of tuberculosis notifications in Ethiopia. Thus, the aim this study was to determine the prevalence, trend and seasonality of tuberculosis. Methods: A hospital-based retrospective study was conducted by reviewing all available patients’ data from January 2015 to April 2019 at Hiwot Fana Specialized University Hospital. Socio-demographic characteristics and results of the GeneXpert assay were taken from the registration book. The data were entered into EpiData 3.1 and analyzed by using the Statistical Package for Social Sciences (SPSS) version 20. Bivariate and multivariate analysis with a 95% confidence interval was undertaken to check the association between prevalence of tuberculosis and dependent variables. Result: From a total of 8001 samples tested for Genexpert, the overall prevalence of Mycobacterium tuberculosis and rifampicin resistance was found to be 1,254 (15.7%) and 53(4.1%), respectively. Trend of tuberculosis proportion was downwardly decreased from 19.3% in 2015, 18.6% in 2016, 18.4% in 2017, 13.5% in 2018 to 13.0% in 2019 ( P- value < 0.001) in all consecutive years throughout the study period. The maximum tuberculosis cases were reported during autumn 454(17.1%) and summer 310 (17.2%) season of calendar year. Age group of 15-29 (adjusted odds ratio (AOR) 1.7, 95% confidence interval (CI) 1.41, 1.98), male sex (AOR 0.84, 95% CI 0.75, 0.96), relapse of tuberculosis (AOR 0.51, 95% CI 0.35-0.78), and being HIV positive (AOR 0.51, 95% CI 0.3, 0.86) were found to be factors associated with tuberculosis. Conclusions: Trend of tuberculosis was decreased year to year. However, still high prevalence is observed with different seasonal variation. Thus, understanding and managing of tuberculosis in seasonal variation, improving case detection rate and controlling the most powerful factors are recommended steps to tackle the problem in Ethiopia.