A systematic Review of Codes Used to Determine the Presence of Hypertension in Routinely Collected Electronic Healthcare Record (EHRs) Data.

Abstract

Abstract Background: Hypertension, or high blood pressure, is a global health concern that plays a significant role in various serious conditions, including kidney disease, heart disease, and stroke. Electronic healthcare records (EHRs) have become an indispensable tool in researching hypertension, but the inconsistency in defining hypertension across different EHRs can affect the reliability and reproducibility of research findings. Objectives: This systematic review aims to identify and analyse the coding systems and code lists used in defining hypertension within EHRs in various research studies. By investigating most frequent codes and coding systems utilised across multiple databases, the review aims to promote more accurate, reliable, and comparable study outcomes. Design: The study encompasses research conducted from January 2010 to January 2023, specifically focusing on the utilisation of electronic medical records for hypertension investigation. To ensure accuracy in identifying hypertension cases, codes were extracted and analysed from various clinical coding systems. These codes are integral in defining hypertension within the studies included in the research. Results: The findings reveal a diverse array of coding systems employed across different studies. The ICD-10 system emerged as the most prevalent, encompassing approximately 44% of the total codes in use, followed by ICD-9, accounting for about 32%. Other systems, such as Read Version 2 and ICD-11, were rarely used, while UK Biobank self-diagnosis, SNOMED CT, ICPC, CTV3, and Medcode were utilised at varying frequencies. The ICD-11 system, launched in Jan 2022, has only been implemented in two distinct research studies. Conclusion: The varying utilisation of coding systems in hypertension research underscores the complexity of standardising this critical health metric across studies. This review highlights the dominant use of the ICD-10 system, the substantial use of the ICD-9 system, and the growing but still limited adoption of newer coding systems like ICD-11. It emphasises the need for consistent adoption of standardised codes to improve the coherence and comparability of hypertension research and to provide a more unified understanding of this global health issue.