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  • Impact of Hospital Volume on AHRQ Patient Safety Indicators in Electively Treated Unruptured Cerebral Aneurysms

    Final Number:

    Chad Washington MS MD MPHS; Brandon Burnsed MD; Robert Dambrino BS; Jacob K Greenberg MD MSCI; Gustavo Gustavo Luzardo; Gregory J. Zipfel MD

    Study Design:

    Subject Category:
    Aneurysm/Subarachnoid Hemorrhage

    Meeting: AANS/CNS Cerebrovascular Section 2016 Annual Meeting

    Introduction: The Agency of Healthcare Research and Quality (AHRQ) has defined Patient Safety Indicators (PSIs) for assessments in the safety of inpatient care. This study defines the rates of PSIs and evaluates the impact of hospital volume on these indicators in patients treated electively for intracranial aneurysms.

    Methods: Using the 2002-2011 Nationwide Inpatient Sample, patients treated electively for a nonruptured cerebral aneurysm with clipping or coiling were selected. Patients were evaluated for PSIs defined by AHRQ specified ICD-9 codes. These included: retained foreign body, postoperative hemorrhage, respiratory failure, pulmonary embolism, and sepsis, among others. Hospitals were categorized by treatment volume into: group 1 (<10), group 2 (>=10 and <20), group 3 (>=20 and <30), or group 4 (>=30).

    Results: A total of 68,938 patients underwent treatment for an unruptured cerebral aneurysm. There were 5,965 (8.7%) PSIs. The most common PSIs were respiratory failure (4%) and postoperative hematoma (2.8%). The overall mortality rate was 0.7%. In patients without a PSI, mortality was 0.2% and with a PSI, it was 6.7%. An increased risk of death was associated with a PSI (OR 48.9, CI 39.1-61.3). In lowest volume centers the rate of PSI was 11.4% with an associated mortality of 1.5%. This is compared to the highest volume centers with a rate of PSI of 8.1% and mortality of 0.6%. In multivariate analysis, patients treated at the lowest volume centers where more likely to suffer a PSI (OR 1.4, CI 1.2-1.5) and mortality (OR 2.0, CI 1.5-2.5).

    Conclusions: PSIs occur relatively frequently in patients treated for unruptured aneurysms and are strongly correlated with inpatient mortality. There is an additional correlation between hospital volume and the occurrence of these events. Patients treated at higher volume centers have significantly lower rates of PSIs and mortality compared to the lowest volume centers.

    Patient Care: Patient safety is an integral part of the daily care of cerebrovascular patients. Additionally, ways of analyzing patient safety via administrative data is becoming increasingly prevalent in today's healthcare landscape. This research will provide a baseline measure by physicians can assess their own outcomes in treating unruptured cerebral aneurysms. From this they will be able to identify areas within their practice for which improvement is needed. Also, on a national level, this information will prove valuable in helping identify treatment volume thresholds that can be used in defining Stroke Center status.

    Learning Objectives: By the conclusion of this session, participants should be able to: 1) Understand the importance of Patient Safety Indicators in outcomes related to the treatment of unruptured cerebral aneurysms, 2) Describe the relationship between hospital treatment volumes and the rate of occurrence of Patient Safety Indicators, and 3) Identify areas within their own practices where patient safety issues can be analyzed and improved.


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