Toward Optimizing Risk Adjustment in the Dutch Surgical Aneurysm Audit

Background: To compare hospital outcomes of aortic aneurysm surgery, casemix correction for preoperative variables is essential. Most of these variables can be deduced from mortality risk prediction models. Our aim was to identify the optimal set of preoperative variables associated with mortality to establish a relevant and efficient casemix model.Methods: All patients prospectively registered between 2013 and 2016 in the Dutch Surgical Aneurysm Audit (DSAA) were included for the analysis. After multiple imputation for missing variables, predictors for mortality following univariable logistic regression were analyzed in a manual backward multivariable logistic regression model and compared with three standard mortality risk prediction models: Glasgow Aneurysm Score (GAS, mainly clinical parameters), Vascular Biochemical and Haematological Outcome Model (VBHOM, mainly laboratory parameters), and Dutch Aneurysm Score (DAS, both clinical and laboratory parameters). Discrimination and calibration were tested and considered good with a C-statistic &gt; 0.8 and Hosmer-Lemeshow (H-L) P &gt; 0.05. Results: There were 12,401 patients: 9,537 (76.9%) elective patients (EAAA), 913 (7.4%) acute symptomatic patients (SAAA), and 1,951 (15.7%) patients with acute rupture (RAAA). Overall postoperative mortality was 6.5%; 1.8% after EAAA surgery, 6.6% after SAAA, and 29.6% after RAAA surgery. The optimal set of independent variables associated with mortality was a mix of clinical and laboratory parameters: gender, age, pulmonary comorbidity, operative setting, creatinine, aneurysm size, hemoglobin, Glasgow coma scale, electrocardiography, and systolic blood pressure (C-statistic 0.871). External validation overall of VBHOM, DAS, and GAS revealed C-statistics of 0.836, 0.782, and 0.761, with an H-L of 0.028, 0.00, and 0.128, respectively.Conclusions: The optimal set of variables for casemix correction in the DSAA comprises both clinical and laboratory parameters, which can be collected easily from electronic patient files and will lead to an efficient casemix model.</p

Toward Optimizing Risk Adjustment in the Dutch Surgical Aneurysm Audit

Background: To compare hospital outcomes of aortic aneurysm surgery, casemix correction for preoperative variables is essential. Most of these variables can be deduced from mortality risk prediction models. Our aim was to identify the optimal set of preoperative variables associated with mortality to establish a relevant and efficient casemix model.Methods: All patients prospectively registered between 2013 and 2016 in the Dutch Surgical Aneurysm Audit (DSAA) were included for the analysis. After multiple imputation for missing variables, predictors for mortality following univariable logistic regression were analyzed in a manual backward multivariable logistic regression model and compared with three standard mortality risk prediction models: Glasgow Aneurysm Score (GAS, mainly clinical parameters), Vascular Biochemical and Haematological Outcome Model (VBHOM, mainly laboratory parameters), and Dutch Aneurysm Score (DAS, both clinical and laboratory parameters). Discrimination and calibration were tested and considered good with a C-statistic &gt; 0.8 and Hosmer-Lemeshow (H-L) P &gt; 0.05. Results: There were 12,401 patients: 9,537 (76.9%) elective patients (EAAA), 913 (7.4%) acute symptomatic patients (SAAA), and 1,951 (15.7%) patients with acute rupture (RAAA). Overall postoperative mortality was 6.5%; 1.8% after EAAA surgery, 6.6% after SAAA, and 29.6% after RAAA surgery. The optimal set of independent variables associated with mortality was a mix of clinical and laboratory parameters: gender, age, pulmonary comorbidity, operative setting, creatinine, aneurysm size, hemoglobin, Glasgow coma scale, electrocardiography, and systolic blood pressure (C-statistic 0.871). External validation overall of VBHOM, DAS, and GAS revealed C-statistics of 0.836, 0.782, and 0.761, with an H-L of 0.028, 0.00, and 0.128, respectively.Conclusions: The optimal set of variables for casemix correction in the DSAA comprises both clinical and laboratory parameters, which can be collected easily from electronic patient files and will lead to an efficient casemix model.</p

Darmkankerchirurgie sinds het bevolkingsonderzoek: Veranderingen in volume en wachttijden onderzocht

Objective To investigate the impact of the Netherlands national colorectal cancer screening programme on the number of surgical resections for colorectal carcinoma and on waiting times for surgery. Design Descriptive study. Method Data were extracted from the Dutch Surgical Colorectal Audit. Patients with primary colorectal cancer surgery between 20112015 were included. The volume and median waiting times for the years 20112015 are described. Waiting times from first tumor positive biopsy until the operation (biopsyoperation) and first preoperative visit to the surgeon until the operation (visitoperation) are analyzed with a univariate and multivariate linear regression analysis. Separate analysis was done for visitoperation for academic and nonacademic hospitals and for screening compared to nonscreening patients. Results In 2014 there was an increase of 1469 (15%) patients compared to 2013. In 2015 this increase consisted of 1168 (11%) patients compared to 2014. In 2014 and 2015, 1359 (12%) and 3111 (26%) patients were referred to the surgeon through screening, respectively. The median waiting time of biopsyoperation significantly decreased (ß: 0.94, 95%BI) over the years 20142015 compared to 20112013. In nonacademic hospitals, the waiting time visitoperation also decreased significantly (ß: 0.89, 95%BI 0.870.90) over the years 20142015 compared to 20112013. No difference was found in waiting times between patients referred to the surgeon through screening compared to nonscreening. Conclusion There is a clear increase in volume since the introduction of the colorectal cancer screening programme without an increase in waiting time until surgery

Surgery for colorectal cancer since the introduction of the Netherlands national screening programme Investigations into changes in number of resections &amp; waiting times for surgery

Objective To investigate the impact of the Netherlands national colorectal cancer screening programme on the number of surgical resections for colorectal carcinoma and on waiting times for surgery. Design Descriptive study. Method Data were extracted from the Dutch Surgical Colorectal Audit. Patients with primary colorectal cancer surgery between 20112015 were included. The volume and median waiting times for the years 20112015 are described. Waiting times from first tumor positive biopsy until the operation (biopsyoperation) and first preoperative visit to the surgeon until the operation (visitoperation) are analyzed with a univariate and multivariate linear regression analysis. Separate analysis was done for visitoperation for academic and nonacademic hospitals and for screening compared to nonscreening patients. Results In 2014 there was an increase of 1469 (15%) patients compared to 2013. In 2015 this increase consisted of 1168 (11%) patients compared to 2014. In 2014 and 2015, 1359 (12%) and 3111 (26%) patients were referred to the surgeon through screening, respectively. The median waiting time of biopsyoperation significantly decreased (ß: 0.94, 95%BI) over the years 20142015 compared to 20112013. In nonacademic hospitals, the waiting time visitoperation also decreased significantly (ß: 0.89, 95%BI 0.870.90) over the years 20142015 compared to 20112013. No difference was found in waiting times between patients referred to the surgeon through screening compared to nonscreening. Conclusion There is a clear increase in volume since the introduction of the colorectal cancer screening programme without an increase in waiting time until surgery.</p

Patients with a Ruptured Abdominal Aortic Aneurysm Are Better Informed in Hospitals with an "EVAR-preferred" Strategy: An Instrumental Variable Analysis of the Dutch Surgical Aneurysm Audit

BACKGROUND: While several observational studies suggested a lower postoperative mortality after minimal invasive endovascular aneurysm repair (EVAR) in patients with a ruptured abdominal aortic aneurysm (RAAA) compared to conventional open surgical repair (OSR), landmark randomized controlled trials have not been able to prove the superiority of EVAR over OSR. Randomized controlled trials contain a selected, homogeneous population, influencing external validity. Observational studies are biased and adjustment of confounders can be incomplete. Instrumental variable (IV) analysis (pseudorandomization) may help to answer the question if patients with an RAAA have lower postoperative mortality when undergoing EVAR compared to OSR. METHODS: This is an observational study including all patients with an RAAA, registered in the Dutch Surgical Aneurysm Audit between 2013 and 2017. The risk difference (RD) in postoperative mortality (30 days/in-hospital) between patients undergoing EVAR and OSR was estimated, in which adjustment for confounding was performed in 3 ways: linear model adjusted for observed confounders, propensity score model (multivariable logistic regression analysis), and IV analysis (two-stage least square regression), adjusting for observed and unobserved confounders, with the variation in percentage of EVAR per hospital as the IV instrument. RESULTS: 2419 patients with an RAAA (1489 OSR and 930 EVAR) were included. Unadjusted postoperative mortality was 34.9% after OSR and 22.6% after EVAR (RD 12.3%, 95% CI 8.5-16%). The RD adjusted for observed confounders using linear regression analysis and propensity score analysis was, respectively, 12.3% (95% CI 9.6-16.7%) and 13.2% (95%CI 9.3-17.1%) in favor of EVAR. Using IV analysis, adjusting for observed and unobserved confounders, RD was 8.9% (95% CI -1.1-18.9%) in favor of EVAR. CONCLUSIONS: Adjusting for observed confounders, patients with an RAAA undergoing EVAR had a significant better survival than OSR in a consecutive large cohort. Adjustment for unobserved confounders resulted in a clinical relevant RD. An "EVAR preference strategy" in patients with an RAAA could result in lower postoperative mortality