Validation of ICD-10-CM Diagnostic Codes for Identifying Patients with ST-Elevation and Non-ST-Elevation Myocardial Infarction in a National Health Insurance Claims Database

Abstract

Purpose

Distinguishing ST-elevation myocardial infarction (STEMI) and non-ST-elevation myocardial infarction (NSTEMI) is crucial in acute myocardial infarction (AMI) research due to their distinct characteristics. However, the accuracy of International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes for STEMI and NSTEMI in Taiwan’s National Health Insurance (NHI) database remains unvalidated. Therefore, we developed and validated case definition algorithms for STEMI and NSTEMI using ICD-10-CM and NHI billing codes.

Patients and Methods

We obtained claims data and medical records of inpatient visits from 2016 to 2021 from the hospital’s research-based database. Potential STEMI and NSTEMI cases were identified using diagnostic codes, keywords, and procedure codes associated with AMI. Chart reviews were then conducted to confirm the cases. The performance of the developed algorithms for STEMI and NSTEMI was assessed and subsequently externally validated.

Results

The algorithm that defined STEMI as any STEMI ICD code in the first three diagnosis fields had the highest performance, with a sensitivity of 93.6% (95% confidence interval [CI], 91.7–95.2%), a positive predictive value (PPV) of 89.4% (95% CI, 87.1–91.4%), and a kappa of 0.914 (95% CI, 0.900–0.928). The algorithm that used the NSTEMI ICD code listed in any diagnosis field performed best in identifying NSTEMI, with a sensitivity of 82.6% (95% CI, 80.7–84.4%), a PPV of 96.5% (95% CI, 95.4–97.4), and a kappa of 0.889 (95% CI, 0.878–0.901). The algorithm that included either STEMI or NSTEMI ICD codes listed in any diagnosis field showed excellent performance in defining AMI, with a sensitivity of 89.4% (95% CI, 88.2–90.6%), a PPV of 95.6% (95% CI, 94.7–96.4%), and a kappa of 0.923 (95% CI, 0.915–0.931). External validation confirmed these algorithms’ efficacy.

Conclusion

Our results provide valuable reference algorithms for identifying STEMI and NSTEMI cases in Taiwan’s NHI database.

Keywords:

• administrative claims data
• acute myocardial infarction
• diagnosis
• ICD-10-CM
• non-ST-elevation myocardial infarction
• ST-elevation myocardial infarction

Ethics Approval and Informed Consent

This study was conducted in accordance with the Declaration of Helsinki and received independent approval from the Institutional Review Board of Ditmanson Medical Foundation Chia-Yi Christian Hospital (IRB 2022088) and the Institutional Review Board of Buddhist Dalin Tzu Chi General Hospital (B11201017). Both institutional review boards approved the exemption of patient informed consent for this retrospective study. The study data were treated with confidentiality to protect the privacy of the participants.

Acknowledgments

Tou-Yuan Tsai and Jen-Feng Lin are co-first authors for this study. The authors thank the help from the Clinical Data Center, Ditmanson Medical Foundation Chia-Yi Christian Hospital for providing administrative and technical support. This study is based in part on data from the Ditmanson Research Database (DRD) provided by Ditmanson Medical Foundation Chia-Yi Christian Hospital. The interpretation and conclusions contained herein do not represent the position of Ditmanson Medical Foundation Chia-Yi Christian Hospital.

Disclosure

The authors report no conflicts of interest in this work.

Additional information

Funding

This research was funded by the Ditmanson Medical Foundation Chia-Yi Christian Hospital Research Program (grant number R111-19). The funders of the research had no role in the design and conduct of the study, interpretation of the data, or decision to submit for publication.