ICD-10-AM codes for cirrhosis and related complications: key performance considerations for population and healthcare studies

Abstract

ObjectiveThe utility of International Classification of Diseases (ICD) codes relies on the accuracy of clinical reporting and administrative coding, which may be influenced by country-specific codes and coding rules. This study explores the accuracy and limitations of the Australian Modification of the 10th revision of ICD (ICD-10-AM) to detect the presence of cirrhosis and a subset of key complications for the purpose of future large-scale epidemiological research and healthcare studies.Design/methodICD-10-AM codes in a random sample of 540 admitted patient encounters at a major Australian tertiary hospital were compared with data abstracted from patients’ medical records by four blinded clinicians. Accuracy of individual codes and grouped combinations was determined by calculating sensitivity, positive predictive value (PPV), negative predictive value and Cohen’s kappa coefficient (κ).ResultsThe PPVs for ‘grouped cirrhosis’ codes (0.96), hepatocellular carcinoma (0.97) ascites (0.97) and ‘grouped varices’ (0.95) were good (κ all >0.60). However, codes under-detected the prevalence of cirrhosis, ascites and varices (sensitivity 81.4%, 61.9% and 61.3%, respectively). Overall accuracy was lower for spontaneous bacterial peritonitis (‘grouped’ PPV 0.75; κ 0.73) and the poorest for encephalopathy (‘grouped’ PPV 0.55; κ 0.21). To optimise detection of cirrhosis-related encounters, an ICD-10-AM code algorithm was constructed and validated in an independent cohort of 116 patients with known cirrhosis.ConclusionMultiple ICD-10-AM codes should be considered when using administrative databases to study the burden of cirrhosis and its complications in Australia, to avoid underestimation of the prevalence, morbidity, mortality and related resource utilisation from this burgeoning chronic disease.

Bacteraemia, sepsis and antibiotic resistance in Australian patients with cirrhosis: a population-based study

“…Details regarding the selection of hospital admissions of patients with cirrhosis have been described previously. 17 Briefly, a patient with cirrhosis was defined by hospitalisation that included at least one ICD‐10‐AM code for cirrhosis (K70.3, K74.4, K74.5, K74.6), hepatocellular carcinoma (HCC) (C22.0), alcoholic hepatic failure (K70.4), hepatic failure unspecified (K72.9), ascites (R18), varices with or without bleeding (I85.0, I85.9, I98.3, I98.2, I86.4), hepatorenal syndrome (K76.7) and portal hypertension (K76.6) as primary diagnosis or other diagnosis. Patients with portal hypertension related to primary thrombophilia (D68.5, D68.6) and schistosomiasis (K77.0, B65.1, B65.9) were classified as non-cirrhotic.…”

“…The accuracy of this algorithm for identification of patients with cirrhosis has been reported to have a 76% negative predictive value (95% CI 0.67 to 0.84) and 88% positive predictive value (95% CI 0.84 to 0.90). 17 …”

“…The accuracy of this algorithm for identification of patients with cirrhosis has been reported to have a 76% negative predictive value (95% CI 0.67 to 0.84) and 88% positive predictive value (95% CI 0.84 to 0.90). 17 The AUSLAB database included 208 220 results linked to this time period and patient cohort; 27 580 were excluded because they were not linked to an admission in the parent cohort; 21 672 were excluded based on age, residence outside Queensland, or private hospital admission. There were a total of 158 968 eligible AUSLAB results: 93 923 were from patients with cirrhosis as defined by the abovementioned algorithm, and 65 045 were from admissions that preceded the cirrhosis diagnosis.…”

Hepatocellular carcinoma amongst Aboriginal and Torres Strait Islander peoples of Australia

“…As the quality of documentation of ICD codes in elective day case admissions (e.g. for a procedures related to portal hypertension) has been reported to be poor [8] , for comorbidities we considered co-existing conditions in any admission during the year of HCC diagnosis. Comorbidity was measured using the Charlson Comorbidity Index (CCI) [9] .…”

“…Curative HCC therapies were considered to be transplantation, liver resection or percutaneous ablation. The presence of cirrhosis was confirmed by relevant ICD-10 codes [8] .…”