Microalbuminuria could improve risk prediction of stroke in patients with transient ischaemic attacks and minor strokes

Abstract

BackgroundTransient ischaemic attacks (TIA) and minor strokes are important risk factors for recurrent strokes; they precede 23% of strokes within 90 days. Identification of patients at high risk of developing further strokes is essential to allow early intervention and avoid the catastrophic outcome of strokes. Elevated urinary albumin excretion rate (AER) is a risk factor and predicts cardiovascular disease, stroke, and mortality. Elevated AER can be detected with a point-of-care bedside test. MethodsPatient demographics and the ABCD2 score were obtained for 150 consecutive patients with TIA who presented to the daily stroke clinic and the stroke unit. The ABCD2 score composite for age, blood pressure, clinical features, duration, and diabetes is the risk score presently used for stratifying patients with TIA. All patients had their albumin:creatinine ratio (ACR) measured from a urine sample obtained during their visit to the clinic or the stroke unit at Royal Devon & Exeter Hospital. Patients were followed up for any events, cardiovascular events, stroke, or death at day 7, 30, and 90. FindingsNine patients had recurrent strokes or TIAs by day 7 and 13 by day 9. Patients who had a recurrent stroke or TIA at day 7 and day 90 had a significantly higher ACR than those who did not have an event (4·00 mg/mmol [95% CI 1·89–8·40] vs 1·89 [95% CI 1·58–2·25]; p=0·03 and 3·73 [95% CI 2·12–6·56] vs 1·85 [95% CI 1·55–2·22]; p=0·02, respectively). After adjustment for sex and ABCD2 score, the 90-day predictive role of ACR persisted for those with versus those without subsequent events (adjusted ACR 3·48 mg/mmol [95% CI 1·96–6·19] vs 1·87 [95% CI 1·56–2·24], p=0·04). Stratification of the population at an ACR of 3.0 mg/mmol identified 39 patients at higher risk. Cox proportional hazards of progressing to stroke by day 90 if ACR was more than 3·0 mg/mmol was 3·2 (95% CI 1·07–9·45, p<0·04). InterpretationIncreased urinary albumin excretion, as detected by urinary ACR, is significantly elevated in patients who present with TIA or minor strokes and go on to have further strokes. The use of clinic urinary ACR test could improve the risk prediction of currently available stroke risk scores such as the ABCD2 score. FundingNational Institute for Health Research and Stroke Research Network.