Date of Award

January 2020

Document Type


Degree Name

Medical Doctor (MD)



First Advisor

Charles C. Matouk

Second Advisor

Angeliki Louvi


INTRODUCTION: In an unprecedented era of soaring healthcare costs, payers and providers alike have started to place increased importance on measuring the quality of surgical procedures as surrogate markers for operative success. Length of hospital stay (LOS) and discharge disposition during index admission are two metrics increasingly used. For the treatment of unruptured cerebral aneurysms, the determinants of extended length of stay and poor discharge disposition remain relatively unknown.

OBJECTIVES: 1) To investigate the influence that patient demographics, such as gender and race, have on post-procedural discharge disposition after treatment of unruptured aneurysms, and 2) To identify the nationwide impact of patient- and hospital-level factors associated with extended LOS following intervention for unruptured cerebral aneurysms.

METHODS: In three separate studies, patients in the National Inpatient Sample database years 2010 to 2014 were queried. Adults (≥ 18 years) presenting with an unruptured cerebral aneurysm were selected using the International Classification of Diseases, Ninth Revision, Clinical Modification coding system. In the first study, patients were categorized by race (White and Black). In the second study, patients were categorized by gender (Male and Female). In the third study, patients were categorized by whether they encountered an extended LOS. For the latter, national estimates were also calculated by using weighting provided by the healthcare cost and utilization project (HCUP). Extended LOS was defined as greater than 75th percentile for the entire cohort (>5 days). Multivariate logistic regression analysis was used to determine the odds ratio for risk-adjusted discharge disposition and extended LOS. The primary outcome was the degree to which the patient demographics, comorbidities, or postoperative complications correlated with discharge disposition or extended LOS.

RESULTS: A total of 7,131 patients were identified, 1,062 (14.9%) of whom identified as Black (White: n=6,069; Black: n=1,062). On average, Black patients experienced one extra day in the hospital (White: 4.0±5.1 days vs. Black: 5.0±6.6 days, p<0.0001), and a lower proportion of routine discharges (White: 82.4% vs. Black: 77.4%, p<0.001). On multivariate analysis, Black patients were 1.6-fold more likely to have a non-routine discharge than White patients [OR: 1.62, 95% CI (1.34, 1.96), p<0.0001).

A total of 8,467 patients were identified, with 6,391 (75.48%) being Female (Male: n=1,076; Female: n=6,391). On average, the Male cohort tended to have longer LOS (Male: 4.75±6.78 days vs. Female: 3.99±4.8\\8 days, p<0.0001), and a slightly higher proportion of routine discharges (Male: 83.2% vs. Female: 81.2%, p=0.01). On multivariate analysis, being Female was not significantly associated with routine discharge [OR: 0.87, 95% CI (0.74, 1.01), p=0.07).

A total, weighted 46,880 patients were identified with 9,774 (20.8%) patients having had extended LOS (Normal LOS: 37,106; Extended LOS: 9,774). The overall complication rates were greater in the extended LOS cohort (Normal LOS: 7.3% vs. Extended LOS: 43.8%, P<0.001). On average, the extended LOS cohort incurred a total cost nearly twice as large (Normal LOS: $26,050 ± 13,430 vs. Extended LOS: $52,195 ± 37,252, P<0.001) and had more patients encounter non-routine discharges (Normal LOS: 8.5% vs. Extended LOS: 52.5%, P<0.001) compared to the normal LOS cohort. On weighted multivariate logistic regression analysis, multiple patient-specific factors were associated with extended LOS. These included demographics, preadmission comorbidities, choice of procedure, and inpatient complications. The odds ratio for extended LOS was 5.14 (95% CI, 4.30 – 6.14) for patients with 1 complication and 19.58 (95% CI, 15.75 – 24.34) for patients with > 1 complication.

CONCLUSION: Overall, this study suggests that 1) patient gender is not a significant risk factor for discharge disposition of patients undergoing treatment intervention for unruptured cerebral aneurysms and, 2) that racial disparities significantly impact the discharge disposition of patients undergoing treatment intervention for unruptured cerebral aneurysms. Furthermore, this study demonstrates that extended LOS after treatment of unruptured aneurysm is influenced by a number of modifiable patient-specific factors, including both pre- and peri-operative variables. In a cost-conscious healthcare environment, focusing on aspects of patient demographics and inpatient care may allow for significant improvement in the care provided while simultaneously reducing costs.


This thesis is restricted to Yale network users only. It will be made publicly available on 09/10/2022