The ABCD and ABCD2 as predictors of stroke in transient ischemic attack clinic outpatients: a retrospective cohort study over 14 years

• Published in: QJM : An International Journal of Medicine 2010-09, Vol.103 (9), p.679-685
• Main Authors: Harrison, J.K., Sloan, B., Dawson, J., Lees, K.R., Morrison, D.S.
• Format: Article
• Language: English
• Subjects: Aged; Ambulatory Care Facilities; Biological and medical sciences; Cohort Studies; Female; General aspects; Humans; Ischemic Attack, Transient - complications; Male; Medical sciences; Miscellaneous; Neurology; Predictive Value of Tests; Public health. Hygiene; Public health. Hygiene-occupational medicine; Retrospective Studies; Risk Factors; Severity of Illness Index; Stroke - etiology; Stroke - prevention & control; Time Factors; Vascular diseases and vascular malformations of the nervous system
• ISSN: 1460-2725; 1460-2393
• DOI: 10.1093/qjmed/hcq108

Background: The ABCD and ABCD2 scores have been validated for use as predictors of stroke in community populations up to 90 days after a transient ischemic attack (TIA). TIA outpatient clinics may see a selective group of patients who have not had an early stroke but may be at raised risk in the medium to long term and therefore benefit from preventive treatment. Aim: To describe the prognostic values of the ABCD and ABCD2 scores on long-term stroke risk. Design: Retrospective cohort study of TIA clinic outpatients followed for up to 14 years. Methods: Absolute and relative stroke risks, Kaplan–Meier survival curves and cumulative stroke incidence were calculated. Receiver Operating Characteristic curves (ROCs) and areas under the curve were calculated for both scores. Results: Seven hundred and ninety-five patients were included and 138 (17.3%) experienced a stroke within 13.8 years follow-up after first TIA clinic visit, a crude risk of 26.3 per 1000 person-years. Compared with baseline scores of 0–2, risk ratios for ABCD of 3–4 were 2.95 (95% CI 1.52–6.40), and for 5–6 were 3.42 (95% CI 1.72–7.54); for the ABCD2, risk ratios for 3–4 were 2.68 (95% CI 1.37–5.84), and for 5–7 were 3.55 (95% CI 1.80–7.79). Scores of ≥3 for either ABCD or ABCD2 predicted raised stroke risks at 90 days, 1, 5 and 10 years. Areas under the curve were 0.619 (95% CI 0.571–0.668) and 0.630 (95% CI 0.582–0.677) for the ABCD and ABCD2 scores, respectively. Conclusion: ABCD and ABCD2 scores of ≥3 may be clinically useful in identifying TIA outpatients at raised risk of stroke in the medium to long term.