Patient comorbidities, aneurysm location, and surgical/intensive care procedures
| Variables | Low (n=7940) | Intermediate (n=20 075) | High (n=5825) | P value |
| Frailty risk score | ||||
| Mean±SD | 2.7±1.6 | 9.7±2.8 | 18.7±3.0 | <0.001 |
| Comorbidities (%) | ||||
| Seizure | 1.3 | 8.4 | 16.2 | <0.001 |
| Neurological deficit associated with subarachnoid hemorrhage | 0.1 | 0.6 | 1.0 | 0.002 |
| Coma | 0.9 | 5.5 | 7.9 | <0.001 |
| Aphasia | 1.8 | 9.4 | 21.8 | <0.001 |
| Dysphagia | 2.6 | 15.7 | 34.9 | <0.001 |
| Cranial nerve palsy | 3.6 | 4.0 | 4.5 | 0.527 |
| Diplopia | 2.1 | 2.3 | 1.8 | 0.581 |
| Hypertensive chronic kidney disease | 0.4 | 3.6 | 6.2 | <0.001 |
| Personal history of transient ischemic attack | 3.4 | 3.9 | 3.4 | 0.633 |
| Headache | 4.8 | 3.2 | 3.7 | 0.010 |
| Affective disorder | 12.8 | 16.3 | 17.1 | 0.002 |
| Smoking | 24.8 | 23.5 | 20.3 | 0.018 |
| Congestive heart failure | 3.1 | 8.1 | 11.1 | <0.001 |
| Cardiac arrhythmias | 12.7 | 23.0 | 30.9 | <0.001 |
| Valvular disease | 1.3 | 3.4 | 3.9 | <0.001 |
| Pulmonary circulation disorders | 1.1 | 3.3 | 4.3 | <0.001 |
| Peripheral vascular disorders | 4.7 | 5.9 | 6.1 | 0.156 |
| Hypertension, combined | 63.5 | 71.2 | 73.6 | <0.001 |
| Paralysis | 0.9 | 15.6 | 53.6 | <0.001 |
| Other neurological disorders | 14.2 | 43.9 | 64.0 | <0.001 |
| Chronic pulmonary disease | 10.1 | 14.4 | 13.2 | <0.001 |
| Diabetes, uncomplicated | 7.5 | 6.8 | 6.0 | 0.321 |
| Renal failure | 1.0 | 5.0 | 8.5 | <0.001 |
| Hypothyroidism | 6.4 | 8.1 | 7.6 | 0.076 |
| Liver disease | 1.8 | 3.5 | 3.0 | 0.003 |
| Peptic ulcer disease | 0.2 | 0.3 | 1.4 | 0.017 |
| Coagulopathy | 4.3 | 7.6 | 8.3 | <0.001 |
| Obesity | 12.5 | 14.6 | 12.6 | 0.074 |
| Weight loss | 2.7 | 9.4 | 16.3 | <0.001 |
| Fluid and electrolyte disorders | 33.2 | 70.0 | 86.6 | <0.001 |
| Deficiency anemias | 2.1 | 2.9 | 4.1 | 0.009 |
| Alcohol abuse | 4.1 | 6.9 | 8.3 | <0.001 |
| Current aspirin use | 10.5 | 10.5 | 9.4 | 0.554 |
| Current anticoagulant use | 2.3 | 2.9 | 2.3 | 0.301 |
| Aneurysm location (%) | <0.001 | |||
| Anterior | ||||
| Carotid siphon bifurcation | 4.1 | 3.0 | 3.3 | |
| Middle cerebral artery | 6.2 | 7.3 | 10.9 | |
| Anterior communicating artery | 26.9 | 27.4 | 27.8 | |
| Posterior | ||||
| Posterior communicating artery | 21.4 | 19.6 | 19.9 | |
| Basilar artery | 5.5 | 6.5 | 4.3 | |
| Vertebral artery | 0.8 | 1.9 | 2.3 | |
| Unspecified | 35.1 | 34.2 | 31.5 | |
| Procedures (%) | ||||
| External ventricular drain | 25.3 | 51.8 | 60.3 | <0.001 |
| Ventriculo-peritoneal shunt | 3.6 | 10.6 | 15.8 | <0.001 |
| Central venous catheter placement | 15.2 | 33.5 | 45.6 | <0.001 |
| Arterial monitoring | 6.4 | 10.6 | 13.6 | <0.001 |
| Fluoroscopy of cerebral arteries with contrast | 52.8 | 55.7 | 63.3 | <0.001 |
| Vasospasm treatment | 2.5 | 6.3 | 10.7 | <0.001 |
| Video-EEG monitoring | 1.4 | 6.0 | 10.0 | <0.001 |
EEG, electroencephalogram