Table 2.
Abnormality at CTA in relation to patient characteristics in 384 included patients
| Patient characteristics | % abnormal CTA | ||
|---|---|---|---|
| Baseline characteristic present, n/N(%) | Baseline characteristic absent, n/N(%) | Prevalence ratiob (95% CI) | |
| Age 45–65 years | 71/183 (38.8%) | 21/119 (17.6%)a | 2.20 (1.43–3.38) |
| Age ≥65 years | 36/82 (43.9%) | 21/119 (17.6%)a | 2.49 (1.57–3.94) |
| Female sex | 79/234 (33.8%) | 49/150 (32.7%) | 1.03 (0.77–1.38) |
| Presentation <6 hr | 83/179 (46.4%) | 44/204 (21.6%) | 2.15 (1.58–2.92) |
| Unilateral headache | 3/30 (10.0%) | 125/354 (35.3%) | 0.28 (0.10–0.84) |
| Aura | 3/21 (14.3%) | 84/296 (28.4%) | 0.50 (0.17–1.46) |
| No Aura recorded | 41/67 (61.2%) | 87/317 (27.4%) | 2.23 (1.72–2.90) |
| Vomiting | 38/186 (20.4%) | 76/172 (44.2%) | 0.46 (0.33–0.64) |
| Seizure | 3/8 (37.5%) | 125/376 (33.2%) | 1.13 (0.46–2.79) |
| Collapse | 12/23 (52.2%) | 116/361 (32.1%) | 1.62 (1.07–2.47) |
| Altered mental state | 4/7 (57.1%) | 124/377 (32.9%) | 1.74 (0.90–3.35) |
| Impaired consciousness | 24/33 (72.7%) | 104/351 (29.6%) | 2.45 (1.89–3.20) |
| Normal glascow coma scale | 82/309 (26.5%) | 46/75 (61.3%) | 0.43 (0.33–0.56) |
| Nuchal rigidity | 25/44 (56.8%) | 73/291 (25.1%) | 2.26 (1.64–3.14) |
| Subjective neurological deficit | 39/97 (40.2%) | 84/282 (29.8%) | 1.35 (1.00–1.83) |
| Pupillary responses abnormal | 14/24 (58.3%) | 109/353 (30.9%) | 1.89 (1.30–2.74) |
| Motor deficit | 19/42 (45.2%) | 105/338 (31.1%) | 1.46 (1.01–2.11) |
| Sensory deficit | 10/29 (34.5%) | 113/350 (32.3%) | 1.07 (0.63–1.80) |
| Neurological examination normal | 22/129 (17.1%) | 106/255 (41.6%) | 0.41 (0.27–0.62) |
| Non contrast CT normal | 12/190 (6.3%) | 116/194 (59.8%) | 0.11 (0.06–0.18) |
| Lumbar puncture normal | 6/69 (8.7%) | 6/29 (20.7%) | 0.42 (0.15–1.20) |
| Lumbar puncture hemorrhage | 4/14 (28.6%) | 8/84 (9.5%) | 3.00 (1.04–8.65) |
| Lumbar puncture infectious | 1/10 (10%) | 11/88 (12.5%) | 0.80 (0.12–5.67) |
| Lumbar puncture raised pressure | 1/4 (25%) | 11/94 (11.7%) | 2.14 (0.36–12.74) |
| Neurological history | 17/46 (37.0%) | 106/333 (31.8%) | 1.16 (0.77–1.75) |
| Headache history | 19/82 (23.2%) | 106/299 (35.5%) | 0.65 (0.43–1.00) |
a
Age <45 years was taken as a reference.
b
Prevalence ratio is the proportion of patients with a vascular abnormality with the given baseline characteristic over the proportion in the group without that characteristic. If the ratio is <1 there are less vascular abnormalities in the group with the baseline characteristic, if the ratio is >1 there are more vascular abnormalities in that group.