Spatio-Temporal Analysis of Tuberculosis in Hamadan Province, West of Iran, from 1992 to 2013

Tuberculosis (TB) despite being preventive and treatable still imposes a huge burden of morbidity and mortality in developing and developed countries. We aimed to investigate the spatial and geographical distribution of TB in Hamadan province during 1992-2013. This cross-sectional study was performed in Hamadan province, West of Iran using the surveillance database. We examined the trend for incidence rates of all TB forms including Smear Positive Pulmonary TB (SPPT), Smear Negative Pulmonary TB (SNPT) and Extra pulmonary TB (EPT) per 100,000 populations. Poisson regression model was used to estimate the standardized rates for incidence rate of all types of TB per each county. In this study 3,602 TB patients including 1,359 SPPT, 987 SNPT, and 1,256 EPT were included during 1992-2013. Trend of all types of TB decreased from 1992 to 2013. The Average Annual Percent change (AAPC) for all types of TB was significantly (P<0.05) decreased, AAPC= -6.4 (95% CIs: -10.7, -1.9). Among SPPT, SNPT, and EPT incidence rates, the maximum change was related to SNPT (-11.6; 95% CIs: -24.2, 3), while it was -1.4 (-8.7, 6.4) for SPPT and -5.8 (-11.4, 0.1) for EPT. Our results showed that the incidence of TB in Hamadan province during a 22-year period has decreased 6.4% on average, somehow higher than the national average. Furthermore, our study showed that the risk of extra-pulmonary occurrence in western parts of the province is higher than others parts.