Table 3.
Accuracy of ICD-10-AM code algorithms to identify the presence of cirrhosis
| # | ICD-10-AM algorithm to detect cirrhosis | n identified by algorithm | PPV (95% CI) |
NPV (95% CI) |
κ | Misclassification error (%) |
| 0 | Cirrhosis ‘classic diagnosis’* | 498 | 0.80 (0.77 to 0.84) | 0.69 (0.54 to 0.82) | 0.256 | 20.6 |
| 1 | K70.3, K74.4, K74.5, K74.6 | 349 | 0.96 (0.94 to 0.98) | 0.60 (0.53 to 0.67) | 0.606 | 16.7 |
| 2 | #1+C22.0 | 359 | 0.96 (0.94 to 0.98) | 0.62 (0.55 to 0.69) | 0.632 | 15.2 |
| 3 | #2+K70.4 | 376 | 0.95 (0.92 to 0.97) | 0.65 (0.58 to 0.72) | 0.640 | 14.3 |
| 4 | #3+K72.9 | 385 | 0.94 (0.91 to 0.96) | 0.67 (0.60 to 0.74) | 0.646 | 13.7 |
| 5.1 | #4+K76.6† | 422 | 0.89 (0.86 to 0.92) | 0.70 (0.61 to 0.77) | 0.573 | 15.0 |
| 5.2 | #4+K76.7 | 392 | 0.93 (0.90 to 0.95) | 0.66 (0.58 to 0.74) | 0.615 | 14.6 |
| 5.3 | #4+grouped varices† | 413 | 0.88 (0.85 to 0.91) | 0.75 (0.66 to 0.82) | 0.575 | 14.3 |
| 6 | #5.3+K76.6† | 447 | 0.88 (0.84 to 0.90) | 0.76 (0.67 to 0.84) | 0.557 | 14.4 |
Encounters were identified by the algorithm if they had ≥1 specified code.
*Cirrhosis ‘classic diagnosis’ (Powell et al1) identifies encounters that include ≥1 of the following ICD-10-AM codes: alcoholic fibrosis and sclerosis of liver (K70.2), alcoholic cirrhosis of liver (K70.3), alcoholic hepatic failure (K70.4), chronic hepatic failure (K72.1), fibrosis and cirrhosis of liver (K74.0), primary biliary cirrhosis/cholangitis (K74.3), secondary biliary cirrhosis (K74.4), biliary cirrhosis, unspecified (K74.5), other and unspecified cirrhosis of liver (K74.6), portal hypertension (K76.6), hepatorenal syndrome (K76.7), gastro-oesophageal varices with/without bleeding (I85.0, I85.9, I98.3, I98.2, I86.4) and hepatocellular carcinoma (HCC) (C22.0). Patients with portal hypertension related to primary thrombophilia (D68.5, D68.6) and schistosomiasis (K77.0, B65.1, B65.9) are classified as non-cirrhotic.
†Patients with primary thrombophilia codes (D68.5, D68.6; n=2 in our cohort) and schistosomiasis (K77.0, B65.1, B65.9; n=0 in our cohort) classified as non-cirrhotic.
ICD-10-AM, Australian Modification of the 10th revision of the International Classification of Diseases; NPV, negative predictive value; PPV, positive predictive value.