Statistical & Clinical Analysis
ASTRAL Score Formula: Acute Ischemic Stroke 3-Month Unfavorable Outcome
Calculate Georgios Ntaios & Patrik Michel’s integer ASTRAL score = INT(Age / 5) + NIHSS + 2*Onset>3h + 2*VisualField + 1*AbnormalGlucose + 3*DecreasedLOC for 3-month mRS > 2 prediction.
Six emergency-room bedside integers—INT(Age / 5) + exact NIHSS + 4 weighted clinical flags!
Georgios Ntaios, Patrik Michel, et al. (2012, Neurology — Acute Stroke Registry and Analysis of Lausanne, externally validated in Athens, Vienna, and Chinese CNSR cohorts with AUC 0.85–0.90) constructed an immediately memorizable integer score predicting unfavorable 3-month outcome (mRS 3–6): (A) Age divided by 5, truncated down INT(Age / 5) (1 point per 5 years of life); (S) exact admission NIHSS score (0–42);
(T) Time from onset to admission > 3 hours (+2 pts); (R) Range of visual fields—any visual field defect (+2 pts); (A) Acute blood glucose > 7.3 mmol/L (> 131 mg/dL) OR < 3.7 mmol/L (< 66 mg/dL) (+1 pt); and (L) decreased Level of consciousness (+3 pts)! In a 72-year-old patient (INT(72/5) = 14) with NIHSS = 11, onset > 3h (+2), hemianopia (+2), glucose 8.4 mmol/L (+1), and alert LOC (0), ASTRAL = 30 (elevated unfavorable risk, vs. 13 in a mild early stroke)!
| Acute Stroke Admission Profile | INT(Age/5) + NIHSS Base | ASTRAL Total Integer Score | 3-Month Unfavorable (mRS 3–6) Risk |
|---|---|---|---|
| Age 72 (14) + NIHSS 11 + >3h + Visual + Glu | 14 + 11 = 25 | 30 Points | High Unfavorable Outcome Risk (ASTRAL >= 25) |
| Age 54 (10) + NIHSS 3, <3h, Normal Glu/LOC | 10 + 3 = 13 | 13 Points | Low Unfavorable Risk (< 15% mRS 3–6) |
| Invalid Age < 18 or NIHSS > 42 | Error Guard | "Invalid ASTRAL Admission Inputs" | Clinical Bounds Guard |
Ntaios-Michel ASTRAL Integer Score = INT(Age / 5) + NIHSS + 2*T + 2*R + 1*A + 3*L
Computes exact integer ASTRAL score from Age (B2), NIHSS (B3, 0–42), and binary flags B4:B7.
=IF(OR(B2 < 18, B2 > 115, B3 < 0, B3 > 42, MIN(B4:B7) < 0, MAX(B4:B7) > 1), "Invalid ASTRAL Admission Inputs", INT(B2 / 5) + B3 + 2 * B4 + 2 * B5 + B6 + 3 * B7)ASTRAL 3-Month Functional Outcome Risk Tier
Stratifies ASTRAL into Low (< 18), Intermediate (18–24), or High Risk of 3-Month mRS 3–6 (>= 25).
=IF(OR(B2 < 18, B2 > 115, B3 < 0, B3 > 42, MIN(B4:B7) < 0, MAX(B4:B7) > 1), "Invalid ASTRAL Admission Inputs", IF(INT(B2 / 5) + B3 + 2 * B4 + 2 * B5 + B6 + 3 * B7 >= 25, "High Unfavorable Risk (ASTRAL >= 25 — High 3-Mo mRS 3–6 Risk)", IF(INT(B2 / 5) + B3 + 2 * B4 + 2 * B5 + B6 + 3 * B7 >= 18, "Intermediate Risk (ASTRAL 18–24)", "Low Unfavorable Risk (ASTRAL < 18 — Favorable Independence)")))Try the example
Use the original values or change them to test your understanding.