The falling rates of hospital admission, case fatality, and population-based mortality for subarachnoid hemorrhage in England, 1999-2010.

OBJECTIVE In this study, the authors examined trends in population-based hospital admission rates, patient-level case fatality rates (CFRs), and population-based mortality rates for nontraumatic (spontaneous) subarachnoid hemorrhage (SAH) in England. METHODS Population-based admission and mortality data (59,599 people admitted to a hospital with SAH, 1999-2010; 37,836 people whose death certificates mentioned SAH, 1995-2010) were analyzed. RESULTS Hospital admission rates for SAH per million population declined by 18.3%, from 100.4 (95% CI 97.6-103.1) in 1999 to 82.0 (95% CI 79.7-84.4) in 2010. CFRs at less than 30 days per 100 patients decreased by 18.2%, from 29.7 (95% CI 28.5-31.0) in 1999 to 24.3 (95% CI 23.2-25.5) in 2010. Population-based mortality rates per million population, where SAH was recorded as underlying cause of death on the death certificate, declined by 39.8%, from 41.2 (95% CI 39.5-43.0) in 1999 to 24.8 (95% CI 23.6-26.1) in 2010. CONCLUSIONS Population-based hospital admission rates, patient-level CFRs, and population-based mortality rates all declined between 1999 and 2010. Part of the decline in mortality rates for SAH is likely to be attributable to a decline in incidence. It is also, in part, attributable to increased survival after SAH. The available data do not allow us to compare the effects of different treatment methods for SAH on case fatality and mortality. During the period of study, mortality rates declined by almost 40%, and it is likely that there are a number of factors contributing to this substantial improvement in outcomes for SAH patients in England.