Validity of Early Outcomes as Indicators for Comparing Hospitals on Quality of Stroke Care
Authors: Amini Marzyeh , Eijkenaar Frank , Lingsma Hester F. , den Hartog Sanne J. , Olthuis Susanne G. H. , Martens Jasper , van der Worp Bart , van Zwam Wim , van der Hoorn Anouk , Roosendaal Stefan D. , Roozenbeek Bob , Dippel Diederik , van Leeuwen Nikki , Dippel Diederik W. J. , van der Lugt Aad , Majoie Charles B. L. M. , Roos Yvo B. W. E. M. , van Oostenbrugge Robert J. , van Zwam Wim H. , Boiten Jelis , Vos Jan Albert , Brouwer Josje , den Hartog Sanne J. , Hinsenveld Wouter H. , Kappelhof Manon , Compagne Kars C. J. , Goldhoorn Robert‐Jan B. , Mulder Maxim J. H. L. , Jansen Ivo G. H. , Dippel Diederik W. J. , Roozenbeek Bob , van der Lugt Aad , van Es Adriaan C. G. M. , Majoie Charles B. L. M. , Roos Yvo B. W. E. M. , Emmer Bart J. , Coutinho Jonathan M. , Schonewille Wouter J. , Vos Jan Albert , Wermer Marieke J. H. , van Walderveen Marianne A. A. , Staals Julie , van Oostenbrugge Robert J. , van Zwam Wim H. , Hofmeijer Jeannette , Martens Jasper M. , Lycklama à Nijeholt Geert J. , Boiten Jelis , de Bruijn Sebastiaan F. , van Dijk Lukas C. , van der Worp H. Bart , Lo Rob H. , van Dijk Ewoud J. , Boogaarts Hieronymus D. , de Vries J. , de Kort Paul L. M. , van Tuijl Julia , Peluso Jo Jo P. , Fransen Puck , van den Berg Jan S. P. , van Hasselt Boudewijn A. A. M. , Aerden Leo A. M. , Dallinga René J. , Uyttenboogaart Maarten , Eschgi Omid , Bokkers Reinoud P. H. , Schreuder Tobien H. C. M. L. , Heijboer Roel J. J. , Keizer Koos , Yo Lonneke S. F. , den Hertog Heleen M. , Sturm Emiel J. C. , Brouwers Paul , Majoie Charles B. L. M. , van Zwam Wim H. , van der Lugt Aad , Lycklama à Nijeholt Geert J. , van Walderveen Marianne A. A. , Sprengers Marieke E. S. , Jenniskens Sjoerd F. M. , van den Berg René , Yoo Albert J. , Beenen Ludo F. M. , Postma Alida A. , Roosendaal Stefan D. , van der Kallen Bas F. W. , van den Wijngaard Ido R. , van Es Adriaan C. G. M. , Emmer Bart J. , Martens Jasper M. , Yo Lonneke S. F. , Vos Jan Albert , Bot Joost , van Doormaal Pieter‐Jan , Meijer Anton , Ghariq Elyas , Bokkers Reinoud P. H. , van Proosdij Marc P. , Krietemeijer G. Menno , Peluso Jo P. , Boogaarts Hieronymus D. , Lo Rob , Dinkelaar Wouter , Appelman Auke P. A. , Hammer Bas , Pegge Sjoert , van der Hoorn Anouk , Vinke Saman , Dippel Diederik W. J. , van der Lugt Aad , Majoie Charles B. L. M. , Roos Yvo B. W. E. M. , van Oostenbrugge Robert J. , van Zwam Wim H. , Lycklama à Nijeholt Geert J. , Boiten Jelis , Vos Jan Albert , Schonewille Wouter J. , Hofmeijer Jeannette , Martens Jasper M. , van der Worp H. Bart , Lo Rob H. , van Oostenbrugge Robert J. , Hofmeijer Jeannette , Flach H. Zwenneke , Lingsma Hester F. , el Ghannouti Naziha , Sterrenberg Martin , Puppels Corina , Pellikaan Wilma , Sprengers Rita , Elfrink Marjan , Simons Michelle , Vossers Marjolein , de Meris Joke , Vermeulen Tamara , Geerlings Annet , van Vemde Gina , Simons Tiny , van Rijswijk Cathelijn , Messchendorp Gert , Nicolaij Nynke , Bongenaar Hester , Bodde Karin , Kleijn Sandra , Lodico Jasmijn , Droste Hanneke , Wollaert Maureen , Verheesen Sabrina , Jeurrissen D. , Bos Erna , Drabbe Yvonne , Sandiman Michelle , Elfrink Marjan , Aaldering Nicoline , Zweedijk Berber , Khalilzada Mostafa , Vervoort Jocova , Droste Hanneke , Nicolaij Nynke , Simons Michelle , Ponjee Eva , Romviel Sharon , Kanselaar Karin , Bos Erna , Barning Denn , Venema Esmee , Chalos Vicky , Geuskens Ralph R. , van Straaten Tim , Ergezen Saliha , Harmsma Roger R. M. , Muijres Daan , de Jong Anouk , Berkhemer Olvert A. , Boers Anna M. M. , Huguet J. , Groot P. F. C. , Mens Marieke A. , van Kranendonk Katinka R. , Treurniet Kilian M. , Jansen Ivo G. H. , Tolhuisen Manon L. , Alves Heitor , Weterings Annick J. , Kirkels Eleonora L. F. , Voogd Eva J. H. F. , Schupp Lieve M. , Collette Sabine , Groot Adrien E. D. , LeCouffe Natalie E. , Konduri Praneeta R. , Prasetya Haryadi , Arrarte‐Terreros Nerea , Ramos Lucas A. 
Published: April 2023

Background
Insight into outcome variation between hospitals could help to improve quality of care. We aimed to assess the validity of early outcomes as quality indicators for acute ischemic stroke care for patients treated with endovascular therapy (EVT).

Methods and Results

We used data from the MR CLEAN (Multicenter Randomized Controlled Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands) Registry, a large multicenter prospective cohort study including 3279 patients with acute ischemic stroke undergoing EVT. Random effect linear and proportional odds regression were used to analyze the effect of case mix on between‐hospital differences in 2 early outcomes: the National Institutes of Health Stroke Scale (NIHSS) score at 24 to 48 hours and the expanded thrombolysis in cerebral infarction score. Between‐hospital variation in outcomes was assessed using the variance of random hospital effects (tau
2
). In addition, we estimated the correlation between hospitals' EVT‐patient volume and (case‐mix–adjusted) outcomes. Both early outcomes and case‐mix characteristics varied significantly across hospitals. Between‐hospital variation in the expanded thrombolysis in cerebral infarction score was not influenced by case‐mix adjustment (tau
2
=0.17 in both models). In contrast, for the NIHSS score at 24 to 48 hours, case‐mix adjustment led to a decrease in variation between hospitals (tau
2
decreases from 0.19 to 0.17). Hospitals' EVT‐patient volume was strongly correlated with higher expanded thrombolysis in cerebral infarction scores (
r
=0.48) and weakly with lower NIHSS score at 24 to 48 hours (
r
=0.15).

Conclusions
Between‐hospital variation in NIHSS score at 24 to 48 hours is significantly influenced by case‐mix but not by patient volume. In contrast, between‐hospital variation in expanded thrombolysis in cerebral infarction score is strongly influenced by EVT‐patient volume but not by case‐mix. Both outcomes may be suitable for comparing hospitals on quality of care, provided that adequate adjustment for case‐mix is applied for NIHSS score.