Rural Hospitals Face a Higher Burden of Ruptured Abdominal Aortic Aneurysm and Are More Likely to Transfer Patients for Emergent Repair
ABSTRACT The influence of rural hospital location on abdominal aortic aneurysm (AAA) outcomes is unknown. We undertook a study to determine the difference in the risk of ruptured AAA presentation and outcomes after ruptured AAA between rural and urban areas.
Patients in the Nationwide Inpatient Sample from 2001 to 2007, with intact AAA repair or ruptured AAA, were included. Patients transferred from another hospital, with unrecorded hospital ZIP code, or age less than 50 years were excluded. Health system variables were obtained from the Area Resource File. Vascular surgeon census was determined from the Society for Vascular Surgery online registry. Multivariable logistic regression was used to analyze outcomes in patients with AAA, adjusting for patient, hospital, and health system variables.
Rural hospital location was associated with higher risk of ruptured AAA presentation (odds ratio [OR] 2.46, 95% CI 1.90 to 3.19) and transfer to another hospital without ruptured AAA repair (9.3% vs 1.4%, p < 0.001). The adjusted risk of death was similar for patients with ruptured AAA admitted to rural and urban hospitals (OR 0.96, 95% CI 0.73 to 1.27). Hospital elective AAA repair volume less than 15 was a risk factor for death after ruptured AAA.
Rural hospitals face a disproportionate burden of ruptured AAA and are more likely to transfer patients with ruptured AAA without performing repair, compared with urban hospitals. Solutions to rural disparity in ruptured AAA outcomes should focus on improving rural patients' access to vascular surgeons for elective and emergent AAA repair.
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ABSTRACT: Instrumental variable analysis is an increasingly popular method in comparative effectiveness research (CER). In theory, the instrument controls for unobserved and observed patient characteristics that affect the outcome. However, the results of instrumental variable analyses in observational settings may be biased if the instrument and outcome are related through an unadjusted third variable: an "instrument-outcome confounder." The authors identified published CER studies that used instrumental variable analysis and searched the literature for potential confounders of the most common instrument-outcome pairs. Of the 187 studies identified, 114 used 1 or more of the 4 most common instrument categories: distance to facility, regional variation, facility variation, and physician variation. Of these, 65 used mortality as an outcome. Potential unadjusted instrument-outcome confounders were observed in all studies, including patient race, socioeconomic status, clinical risk factors, health status, and urban or rural residency; facility and procedure volume; and co-occurring treatments. Only 4 (6%) instrumental variable CER studies considered potential instrument-outcome confounders outside the study data. Many effect estimates may be biased by the failure to adjust for instrument-outcome confounding. The authors caution against overreliance on instrumental variable studies for CER.Annals of internal medicine 07/2014; 161(2):131-8. DOI:10.7326/M13-1887 · 16.10 Impact Factor
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ABSTRACT: Within Southwestern Ontario, abdominal aortic aneurysm (AAA) surgery has been centralized to a single university-affiliated medical center. The referral area serves 1.9 million people and includes community hospitals with limited vascular surgery capabilities. We reviewed the role of patients' travel distance, geographic location, and socioeconomic status (SES) to determine if centralization of endovascular programs results in disparity in access to endovascular surgery. We hypothesized that patients would travel a longer distance to specifically seek elective endovascular surgery while having open and emergent surgery closer to home. All patients who underwent AAA repair (July 2005-June 2010) at London Health Science Centre were identified from the vascular surgery database. Method of repair, clinical presentation, and in-hospital mortality were recorded. Travel distance from each patient's home to our hospital and rural versus urban status was determined for each patient. SES was determined by using a previously validated, locally developed deprivation index. During this 5-year period, 1,243 patients were included in our analysis; 46.8% (n = 581) underwent endovascular repair (EVAR) and 53.2% (n = 662) underwent open repair. For elective cases, the in-hospital mortality rate was 2.0% (n = 11) for EVAR and 3.6% (n = 20) for open repair (P = 0.1). There was no difference in clinical presentation between SES groups, but open repair was more frequently used in patients of lower SES compared to higher SES (odds ratio = 1.32; 95% confidence interval: 1.02-1.72). Travel distance and rural/urban status were not associated with increased odds of EVAR. When ruptured aneurysms were excluded, elective patients of lower SES continued to have a higher rate of open surgery. Despite the centralization of endovascular programs in Canada, patients do not appear to be traveling a longer distance for EVAR while having open repairs closer to home as we expected. We did note that higher SES was associated with increased odds of EVAR, which may suggest a health care access bias for EVAR for patients of higher SES. Larger, population-based studies at the provincial or national level could confirm these initial findings.Annals of Vascular Surgery 09/2013; 27(8). DOI:10.1016/j.avsg.2013.02.020 · 1.03 Impact Factor
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ABSTRACT: Although mortality after elective abdominal aortic aneurysm (AAA) repair has steadily declined, operative mortality for a ruptured AAA (rAAA) remains high. Repair of rAAA at hospitals with a higher elective aneurysm workload has been associated with lower mortality rates irrespective of the mode of treatment. This study sought to determine the association between surgeon specialization and outcomes after rAAA repair. The American College of Surgeons National Surgical Quality Improvement Project database from 2005 to 2010 was used to examine the 30-day mortality and morbidity outcomes of patients undergoing rAAA repair by vascular and general surgeons. Multivariable logistic regression analysis was performed for each death and morbidity, adjusting for all independently predictive preoperative risk factors. Survival curves were compared using the log-rank test. We identified 1893 repairs of rAAAs, of which 1767 (96.1%) were performed by vascular surgeons and 72 (3.9%) were performed by general surgeons. There were no significant differences between patients operated on by general vs vascular surgeons in preoperative risk factors or method of repair. Overall 30-day mortality was 34.3% (649 of 1893). After risk adjustment, mortality was significantly lower in the vascular surgery group compared with the general surgery group (odds ratio [OR], 0.51; 95% confidence interval [CI], 0.30-0.86; P = .011). The risk of returning to the operating room (OR, 0.58; 95% CI, 0.35-0.97; P = .038), renal failure (OR, 0.54; 95% CI, 0.31-0.95; P = .034), and a cardiac complication (OR, 0.53; 95% CI, 0.28-0.99; P = .047) were all significantly less in the vascular surgery group. Despite similar preoperative risk factors profiles, patients who were operated on by vascular surgeons had lower mortality, less frequent returns to the operating room, and decreased incidences of postoperative renal failure and cardiac events. These data add weight to the case for further centralization of vascular services.Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 05/2014; DOI:10.1016/j.jvs.2014.03.283 · 2.98 Impact Factor