Days Alive and Out of Hospital as a Measure of Stroke Outcome in Patients Receiving Hyperacute Stroke Intervention
Joseph Donnelly1, Jae Hong2, Luke Boyle4, Vivien Yong5, William Diprose6, Douglas Campbell3, Alan Barber7
1Neurology, Auckland City hospital, 2Neurology, 3Anaesthesiology, Auckland City Hospital, 4Statistics, University of Auckland, 5Neurology, Auckland District Health Board, 6Royal North Shore Hospital, 7Auckland Hospital
Objective:
To assess the criterion and construct validity of DAOH.
Background:
Patient outcome after stroke is frequently assessed with the modified Rankin Scale score, which is a 7-level ordinal scale from 0 – no disability, to 6- dead that is usually obtained by in-person or telephone interviews. The mRS can be prone to bias and can have significant inter-rater variability. Days alive and out of hospital at 90 days (DAOH-90) is an objective, readily available outcome measure that accounts for survival, time spent in hospital or rehabilitation settings, re-admission, and institutionalisation.
Design/Methods:
Consecutive ischemic stroke patients treated with thrombolysis or endovascular thrombectomy were used in this analysis. DAOH-90 was calculated from the national minimum dataset, an administrative nationwide database. mRS was assessed with in-person or telephone interviews. Simple descriptive statistics were applied (median [IQR]). The ability of DAOH-90 to distinguish between the commonly applied cut-points of mRS-90 was assessed using the area under the receiver operating curve (AUROC). Prognostic variables previously validated for mRS were assessed with Spearman’s correlation.
Results:
1278 ischemic stroke patients (714 male, median age 70[59-79], median NIHSS 14[9-20] were included in this study. Overall, median DAOH-90 was 71[29-84] and median mRS-90 was 3 [2-5]. There was a strong association between mRS-90 and DAOH-90 (spearman rho correlation 0.79, p<0.001). AUROC (95% CI) for predicting mRS > 0, mRS >1, mRS>2 were 0.86 (0.84-0.88), AUC 0.88 (0.86-0.90), AUC 0.90 (0.89-0.92) respectively. DAOH-90 was significantly correlated with age (spearman rho -0.13, p<0.001), admission NIHSS (spearman -0.44, p<0.001), Alberta stroke programme early CT score (spearman rho 0.24, p<0.001), and admission blood glucose concentration (spearman -0.24, p<0.001).
Conclusions:
DAOH-90 is statistically valid outcome measure in ischemic stroke that strongly relates to mRS-90. DAOH is an objective, patient-centric outcome measure that can be determined from large datasets and therefore its place in stroke research warrants further study.