Systematic review: development of a consensus code set to identify cirrhosis in electronic health records

BACKGROUND: Electronic health records (EHRs) collate longitudinal data that can be used to facilitate large‐scale research in patients with cirrhosis. However, there is no consensus code set to define the presence of cirrhosis in EHR. This systematic review aims to evaluate the validity of diagnostic coding in cirrhosis and to synthesise a comprehensive set of ICD‐10 codes for future EHR research. METHOD: MEDLINE and EMBASE databases were searched for studies that used EHR to identify cirrhosis and cirrhosis‐related complications. Validated code sets were summarised, and the performance characteristics were extracted. Citation analysis was done to inform development of a consensus code set. This was then validated in a cohort of patients. RESULTS: One thousand six hundred twenty‐six records were screened, and 18 studies were identified. The positive predictive value (PPV) was the most frequently reported statistical estimate and was ≥80% in 17/18 studies. Citation analyses showed continued variation in those used in contemporary research practice. Nine codes were identified as those most frequently used in the literature and these formed the consensus code set. This was validated in diverse patient populations from Europe and North America and showed high PPV (83%–89%) and greater sensitivity for the identification of cirrhosis than the most often used code set in the recent literature. CONCLUSION: There is variation in code sets used to identify cirrhosis in contemporary research practice. A consensus set has been developed and validated, showing improved performance, and is proposed to align EHR study designs in cirrhosis to facilitate international collaboration and comparisons.