Characteristics of Nontraumatic Subarachnoid Hemorrhage in the United States in 2003

Objective: Substantial progress has been made in the diagnosis and treatment of subarachnoid hemorrhage (SAH). However, studies of SAH in the United States do not include information more recent than 2001, precluding analysis of shifts in treatment methods. We examined the epidemiology and in-hospital outcomes of nontraumatic SAH in the United States.

Methods: We analyzed nationally representative data from the 2003 Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project to determine demographic and hospital characteristics, treatments, and in-hospital outcomes of patients with nontraumatic SAH.

Results: In 2003, there were an estimated 31,476 discharges for nontraumatic SAH among patients aged 17 years or older, or 14.5 discharges per 100,000 adults. The in-hospital mortality rate was 25.3%. Microvascular clipping was performed in 7513 discharges, or 23.9% of inpatients with nontraumatic SAH; endovascular coiling was performed in 2849 discharges (9.1%). Adjusted odds of treatment with either procedure were significantly higher in urban teaching hospitals compared with urban nonteaching hospitals (odds ratio, 1.62; 95% confidence interval, 1.00-2.62) or rural hospitals (odds ratio, 3.08; 95% confidence interval, 1.93-4.91).

Conclusion: The in-hospital mortality rate associated with nontraumatic SAH continues to exceed 25%. Although it is unclear how many patients with nontraumatic SAH were actually diagnosed with a cerebral aneurysm, this study suggests that less than one-third of patients hospitalized for SAH receive surgical or endovascular treatment. Prospective studies are needed to elucidate either what systematic coding error is occurring in the national database or why patients may not receive treatment to secure a ruptured aneurysm.