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

Abstract

Purpose

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

Acknowledgments

The authors wish to thank Jan Helldén, Department of Business Intelligence, RSD for contributing to the collection of the data. The authors also wish to thank the staff in the Danish Clinical Quality Program – National Clinical Registries (RKKP) and the Danish Stroke Registry for their work in data collection and delivery.

Author Contributions

SMH and DG conceived the study, performed the analyses, and wrote the first draft. All authors contributed to data analysis, drafting or revising the article, have agreed on the journal to which the article will be submitted, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

The activities of DG are supported by a grant from Odense University Hospital.

Luis Alberto García Rodríguez reports grants from Bayer AG, personal fees from Bayer AG, outside the submitted work.

Rustam Al-Shahi Salman reports grants from British Heart Foundation, grants from The Stroke Association, outside the submitted work.

The authors report no other potential conflicts of interest in this work.

Additional information

Funding

This work is part of a PhD fellowship (SMH) supported by the University of Southern Denmark and the Region of Southern Denmark. The project also received funding from Odense University Hospital (A2926; 70-A3187; 49-A2483) and the A. P. Møller and Chastine Mc-Kinney Møller Foundation (18-L-0214).