Multicenter validation of the max‐ICH Score in intracerebral hemorrhage

OBJECTIVE Outcome prognostication unbiased by early care limitations(ECL) is essential for guiding treatment in patients presenting with intracerebral hemorrhage(ICH). This study aims to determine whether the max-ICH Score provides improved and clinically useful prognostic estimation of functional long-term outcomes after ICH. METHODS This multicenter validation study compared the max-ICH Score's vs the ICH Score's prognostication regarding diagnostic accuracy (discrimination, calibration) and clinical utility using decision curve analysis. We performed a joint investigation of individual participant data of consecutive spontaneous ICH patients(n=4,677) from two retrospective German-wide studies(RETRACE I+II; anticoagulation-associated ICH only) conducted at 22 participating centers, one German prospective single-center study(UKER-ICH; non-anticoagulation-associated ICH only), and one U.S.-based prospective longitudinal single-center study(MGH; both anticoagulation- and non-anticoagulation-associated ICH), treated between January 2006 and December 2015. RESULTS Of 4,677 included ICH patients, 1,017(21.7%) were affected by ECL[German-cohort:15.6%(440/2377); MGH:31.0%(577/1283)]. Validation of long-term functional outcome prognostication by the max-ICH Score provided good and superior discrimination in patients without ECL compared to the ICH Score[Area under the receiver operating curve(AUROC),German-cohort:0.81(0.78-0.83) vs 0.74(0.72-0.77),p<0.01; MGH:0.85(0.81-0.89) vs 0.78(0.74-0.82),p<0.01], and for the entire cohort[AUROC,German-cohort:0.84(0.82-0.86) vs 0.80(0.77-0.82),p<0.01; MGH:0.83(0.81-0.85) vs 0.77(0.75-0.79),p<0.01]. Both scores showed no evidence of poor calibration. The clinical utility investigated by decision curve analysis showed at high threshold probabilities(0.8, aiming to avoid false-positive poor outcome attribution), that the max-ICH Score provided a clinical net-benefit compared to the ICH Score(14.1 vs 2.1 net-predicted poor outcomes per 100 patients). INTERPRETATION The max-ICH score provides valid and improved prognostication of functional outcome after ICH. The associated clinical net-benefit in minimizing false poor outcome attribution may potentially prevent unwarranted care limitations in patients with ICH. This article is protected by copyright. All rights reserved.