The trend analysis of spontaneous subarachnoid hemorrhage mortality in Tianjin from 1999 to 2015

Objective To explore the trend and distribution of spontaneous subarachnoid hemorrhage (SAHs) mortality among the residents with different characteristics from 1999 to 2015 in Tianjin, and to provide basis for prevention and control of SAHs. Methods SAHs mortality data in 1999-2015 were collected from Tianjin population-based mortality surveillance system maintained by Tianjin Center for Disease Control and Prevention (CDC) and permanent residents’ population data were from Tianjin Municipal Public Security Bureau. Standardized mortality rates were calculated for SAHs and adjusted for age and gender using the year 2000 world standard population. Joinpoint regression and Cochran-Armitage trend were used to determine the statistical significance of differences in mortality trends. Results The crude mortality rate of SAHs in Tianjin from 1999 to 2015 was 0.62/100 000 to 1.23/100 000. Adjusted SAHs mortality rate from 1999 to 2009 was 0.56/100 000 to 1.59/100 000, indicating an increased trend (Z=9.88, P<0.001) with an annual percent change (APC) of 10.95%. Adjusted SAHs mortality rate was decreased from 2009 to 2015: 1.59/100 000 to 0.72/100 000 (Z=-6.33, P<0.001) and APC was -10.16%. Those trend changes were similar for male and female residents (P<0.001). The SAHs mortality rate of male (crude: 0.57/100 000-1.22/100 000, standardized: 0.53/100 000-0.75/100 000) was not significantly different with that of female (crude: 0.67/100, 000-1.23/100, 000, standardized: 0.60/100, 000-0.68/100, 000) during the 17 years. SAHs mortality rate increased with age. Adjusted SAHs mortality in urban residents increased from 1999 to 2008 (Z=4.15, P<0.001, APC=6.30%) and decreased in the year from 2008 to 2015 (Z=-5.39, P<0.001, APC=-10.94%). Adjusted SAHs mortality in rural residents increased from 1999 to 2011 (Z=14.79, P<0.001, APC=19.02%) and decreased from 2011 to 2015 (Z=-5.81, P<0.001, APC=-21.22%). The SAHs mortality rate was generally higher in urban residents than in rural residents in 1999-2008, while it was generally higher in rural residents than in urban residents in 2009-2015. Conclusions Our results suggest that SAHs mortality in Tianjin increased from 1999 to 2008 and decreased from 2009 to 2015. Compared with urban residents, rural residents had lower SAHs mortality from 1999 to 2008 and higher SAHs mortality in the recent 7 years. Further efforts to reduce SAHs mortality in Tianjin are needed particularly for the people in rural areas. Key words: Subarachnoid hemorrhage, spontaneous; Mortality; Population surveillance; Epidemiology