Abstract 185: Declining Subarachnoid Hemorrhage Case-Fatality Rates in a Population

Abstract

Introduction: In the last few decades there have been several medical advances in the care of patients with subarachnoid hemorrhage (SAH). But few population-based studies (and none in the United States) have examined outcomes in the same population over time. Methods: All SAHs among residents of the Greater Cincinnati/Northern Kentucky (GCNK) region at least 20 years of age were identified using ICD-9 codes 430-436 and verified via study physician review in four distinct study periods. An incidence rate for each time period was calculated. Baseline characteristics, including demographics, risk factors, and functional status, were ascertained, along with hospital discharge modified Rankin score and all-cause 30- and 90-day case-fatality. Results: We identified 78 SAHs among residents of the GCNK region in 1988, 85 from 7/1993 to 6/1994, 95 in 1999, and 91 in 2005. The incidence of SAH in the four study periods (age-, race-, and sex-adjusted to the 2000 US population) was 9.4, 9.3, 10.0, and 9.0 per 100,000, respectively. Of the 349 SAHs in the study periods, 326 were diagnosed in an ED or hospital setting, while 23 were diagnosed on autopsy alone. All-cause 30- and 90-day case-fatality rates declined significantly from 1988 to 2005 ( Table ), even when all autopsy-alone cases were excluded. Conclusions: While the incidence of SAH remained stable in this population-based region, the 30-day and 90-day case-fatality rates declined significantly. Advances in surgical and medical management, along with systems-based changes such as the emergence of neurocritical care units, have likely led to reduced case-fatality. Future studies should explore the impact of specific factors related to improved case-fatality rates.