What models are available nowadays, and how accurate they are?
Three models are been tested: updated Glasgow Aneurysm Score (GAS), the Vancouver scoring system, the Edinburgh Ruptured Aneurysm Score (ERAS), and the Hardman index
449 patients in ten hospitals with a RAAA (intervention between 2004 and 2011)
The updated GAS score – calculated with the formula: age (years) + 7 for cardiac comorbidity (defined as previous history of myocardial infarction, cardiac surgery, angina pectoris or arrhythmia) + 10 for cerebrovascular comorbidity (defined as previous history of stroke or transient ischemic attack) + 17 for shock (defined as an in hospital systolic blood pressure <80 mmHg) + 14 for renal insufficiency (defined as a pre-operative serum creatinine >160 μmol/L) + 7 for OR
predicted mortality rate (%) =
and the performance of GAS is as follows:
The Vancouver score – calculated with the formula: age (years)*0.062 + loss of consciousness (yes = 1/no = −1)*1.14 + cardiac arrest (yes = 1/no = −1)*0.6
and the performance of Vancouver is as follows:
The ERAS score – calculated with the formula: +1 for best recorded in hospital Glasgow coma scale (GCS) <15, +1 for in hospital systolic blood pressure <90 mmHg, +1 for pre-operative hemoglobin level <5.6 mmol/L. A score of 0 or 1 corresponded with a predicted death rate of 30%, a score of 2 with a predicted death rate of 50%, and a score of 3 with a predicted death rate of 80%.
The AUC of the updated GAS was 0.71 (95% confidence interval [CI] 0.66–0.76), of the Vancouver score was 0.72 (95% CI 0.67–0.77), and of the ERAS was 0.58 (95% CI 0.52–0.65).
After recalibration, predictions by the updated GAS slightly overestimated the death rate, with a predicted death rate 60% versus observed death rate 54% (95% CI 44–64%).
After recalibration, predictions by the Vancouver score considerably overestimated the death rate, with a predicted death rate 82% versus observed death rate 62% (95% CI 52–71%).
Performance of the Hardman index could not be assessed on discrimination and calibration, because in 57% of patients electrocardiograms were missing.