Evidence of better outcomes in patients with aneurysmal subarachnoid hemorrhage treated at higher-volume centers might be expected to result in more of these patients being referred to such centers. The authors evaluated the US National Inpatient Sample for the years 2001 to 2008 for trends in patient admissions for the treatment of ruptured aneurysms at high- and low-volume centers.
The authors determined the number of ruptured aneurysms treated with clipping or coiling annually at low-volume (≤ 20 patients/year) and high-volume (> 20 patients/year) centers and also counted the number of high- and low-volume centers performing each treatment. Hospitalizations for clipping or coiling ruptured aneurysms were identified by cross-matching International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes for the diagnosis of a ruptured aneurysm (ICD-9-CM 430) with procedure codes for clipping (ICD-9-CM 39.51) or coiling (ICD-9-CM 39.52, 39.79, or 39.72) cerebral aneurysms.
In 2001, 31% (435 of 1392) of the patients who underwent clipping and 0% (0 of 122 patients) of those who underwent coiling did so at high-volume centers, whereas in 2008 these numbers increased to 62% (627 of 1016) and 68% (917 of 1351) of patients, respectively. For clipping procedures, the number of low-volume centers significantly declined from 177 in 2001 to 85 in 2008, whereas the number of high-volume centers remained constant at 13–15. For coiling procedures, the number of low-volume centers decreased from 62 in 2001 to 54 in 2008, whereas the number of high-volume centers substantially increased from 0 in 2001 to 16 in 2005 and remained constant thereafter.
The treatment of ruptured cerebral aneurysms increasingly occurs at high-volume centers in the US. This trend is favorable given that better outcomes are associated with the treatment of these lesions at high-volume centers.
Abbreviations used in this paper: ICD-9-CM = International Classification of Diseases, 9th Revision, Clinical Modification; IQR = interquartile range; NIS = National Inpatient Sample; SAH = subarachnoid hemorrhage.
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