(SLC-044) Validity of German ICD-10-GM Diagnosis Codes for Myocardial Infarction against Chart Review of Electronic Health Records

Background: Health insurance claims, coded using the International Classification of Diseases, 10th Revision (ICD-10), are integral for reimbursement and are increasingly used for observational research in cardiovascular medicine. However, until now, these claims have not been validated via gold-standard chart review of electronic health records (EHR) in Germany, leaving uncertainty about their validity.

Objectives: To determine the positive predictive value (PPV) of ICD-10, German Modification (GM), coded claims for myocardial infarction (MI).

Methods: This study utilized patient cases from 2019 to 2023, in which medical claims contained ICD-10 codes relevant to MI. Codes for acute MI included I21.0, I21.1, I21.2, I21.3, I21.4, I21.9, I22.0, I22.1, I22.8, I22.9, and for old MI I25.2. The validation of the codes was performed by identifying the corresponding MI diagnosis through chart review of EHRs. The identification of the diagnosis was carried out by two independent researchers following predefined guidelines. Inter-annotator agreement was assessed to ensure consistency. Diagnoses from charts were categorized into acute MI (further classified into STEMI, NSTEMI) and old MI.

Results: Of the 520 charts reviewed, 370 were for patients coded with acute MI and 150 for old MI. Inter-annotator agreement was 98.3% [95% confidence interval, 95.7%-99.5%]. The PPV was 98.1% [96.1%-99.2%] for acute MI (STEMI 89.9% [86.0%-92.97%], NSTEMI 96.2% [87.0%-99.5%]) and 95.3% [90.6%-98.1%] for old MI.

Conclusions: This is the first validation study ascertaining the validity of ICD-10-GM coded claims for MI via gold-standard chart review in EHRs. Overall, a very high PPV for MI diagnosis was observed. These findings suggest that claims identifying MI are a reliable source for observational studies.