The Validity of Intracerebral Hemorrhage Diagnoses in the Danish Patient Registry and the Danish Stroke Registry

Stine Munk Hald,1,2 Christine Kring Sloth,1 Mikkel Agger,1 Maria Therese Schelde-Olesen,1 Miriam Højholt,1 Mette Hasle,1 Helle Bogetofte,1 Ida Olesrud,1 Stefanie Binzer,3 Charlotte Madsen,1 Willy Krone,4 Luis Alberto García Rodríguez,5 Rustam Al-Shahi Salman,6 Jesper Hallas,7 David Gaist1,2,8 1Department of Neurology, Odense University Hospital, Odense, Denmark; 2Department of Clinical Research, Neurology Research Unit, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark; 3Department of Neurology, Lillebaelt Hospital, Kolding, Denmark; 4Department of Radiology, Odense University Hospital, Odense, Denmark; 5Centro Español Investigación Farmacoepidemiológica (CEIFE), Madrid, Spain; 6Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK; 7Clinical Pharmacology and Pharmacy, Department of Public Health, University of Southern Denmark, Odense, Denmark; 8Odense Patient Data Explorative Network (OPEN), Odense University Hospital, Odense, DenmarkCorrespondence: David GaistDepartment of Neurology, Odense University Hospital, J.B. Winsløwsvej 4, 5000 Odense C, Odense, DenmarkTel +45 65412485Fax +45 65413389Email dgaist@health.sdu.dkPurpose: To establish the validity of intracerebral hemorrhage (ICH) diagnoses in the Danish Stroke Registry (DSR) and the Danish National Patient Registry (DNPR).Patients and Methods: Based on discharge summaries and brain imaging reports, we estimated the positive predictive value (PPV) of a first-ever diagnosis code for ICH (ICD-10, code I61) for all patients in the Region of Southern Denmark (1.2 million) during 2009– 2017 according to either DNPR or DSR. We estimated PPVs for any non-traumatic ICH (a-ICH) and spontaneous ICH (s-ICH) alone (ie, without underlying structural cause). We also calculated the sensitivity of these diagnoses in each of the registers. Finally, we classified the location of verified s-ICH.Results: A total of 3,956 patients with ICH diagnosis codes were studied (DSR only: 87; DNPR only: 1,513; both registries: 2,356). In the DSR, the PPVs were 86.5% (95% CI=85.1– 87.8) for a-ICH and 81.8% (95% CI=80.2– 83.3) for s-ICH. The PPVs in DNPR (discharge code, primary diagnostic position) were 76.2% (95% CI=74.7– 77.6) for a-ICH and 70.2% (95% CI=68.6– 71.8) for s-ICH. Sensitivity for a-ICH and s-ICH was 76.4% (95% CI=74.8– 78.0) and 78.7% (95% CI=77.1– 80.2) in DSR, and 87.3% (95% CI=86.0– 88.5) and 87.7% (95% CI=86.3– 88.9) in DNPR. The location of verified s-ICH was lobar (39%), deep (33.6%), infratentorial (13.2%), large unclassifiable (11%), isolated intraventricular (1.9%), or unclassifiable due to insufficient information (1.3%).Conclusion: The validity of a-ICH diagnoses is high in both registries. For s-ICH, PPV was higher in DSR, while sensitivity was higher in DNPR. The location of s-ICH was similar to distributions seen in other populations.Keywords: stroke, intracerebral hemorrhage, epidemiology, validity, register-based research