Adjusted Hospital Outcomes of Abdominal Aortic Aneurysm Surgery Reported in the Dutch Surgical Aneurysm Audit

Abstract

Mortality in the DSAA was in line with the literature but is not discriminative for hospital comparisons in EAAA. Adjusting for V(p)-POSSUM, revealed no association between hospital volume and treatment or outcome. Risk adjustment for case mix by V(p)-POSSUM in patients with AAAA has been shown to be important.

Failure to Rescue – a Closer Look at Mortality Rates Has No Added Value for Hospital Comparisons but Is Useful for Team Quality Assessment in Abdominal Aortic Aneurysm Surgery in The Netherlands

“…Primarily, FTR was investigated because of the low discriminative ability of the low mortality rates in elective AAA surgery. 6 Indeed, the mean FTR in this study is higher (9.2% EVAR and 13.2% OSR), with more variation, than the mean mortality as described for EAAA patients and was similar to a study in 2015: 9.6% FTR for EVAR and 11.1% FTR for OSR. 22 However hospital variation regarding outliers is disappointing.…”

“…Adjusted mortality, major complication rates, and FTR were compared between hospital volume tertiles. To ensure casemix corrected comparison between hospitals, a multivariable logistic regression analysis was used to adjust outcomes for patient characteristics by variables measured on admission in part based on the re-estimated V(p)-POS-SUM variables on the Dutch population, 6,16,17 including age, gender, systolic blood pressure, heart rate, pulmonary status, cardiac status, pre-operative electrocardiography (ECG), creatinine, Glasgow Coma Scale (GCS), haemoglobin, and operative setting: EAAA, SAAA or RAAA. Hospital comparisons were displayed in funnel plots with 95% confidence intervals: hospital volume versus mortality and major complications, as well as volume of major complications versus FTR.…”

“…4,5 With a mean mortality of 0.9% in EVAR patients in registries such as the Dutch Surgical Aneurysm Audit (DSAA) or 0.6% in the Swedish vascular registry (SWEDVASC), post-operative mortality as a single quality indicator seems to be of limited discriminative value for hospital comparisons. 6,7 Moreover, mortality is dependent on both casemix and hospital performance. 8 To focus on hospital processes, composite outcome measures have been developed that tend to be more related to hospital processes and are less sensitive to errors in risk adjustment.…”

Variation in Surgical Treatment of Abdominal Aortic Aneurysms With Small Aortic Diameters in the Netherlands

“…[4][5][6][7][8] Since 2013, all patients undergoing aortic aneurysm surgery in the Netherlands are registered in a nationwide audit-the Dutch Surgical Aneurysm Audit (DSAA). 9 This audit reported previously that 17% of all patients undergoing elective aneurysm surgery is operated with a smaller diameter than recommended in the guidelines, with variation between hospitals. 10 Other studies have also confirmed variation in practice regarding the aneurysm diameter, nationally and internationally.…”

One year on: Test your knowledge from the previous year

“…What is not true regarding case-mix adjustment and the use of mortality risk prediction models like V-POSSUM? 4 A. The number of events per variable is of influence on model performance B. Case-mix adjustment is necessary to allow accurate hospital comparisons C. Differences between countries and development of techniques over time will necessitate that models are updated D. Since the rate of EVAR varies between hospitals the type of procedure must always be an included variable within the model E. Large patient cohorts with complete data allow the best models to be developed 5.…”