Limitations of conventionally derived chronic liver disease mortality rates: Results of a comprehensive assessment

Abstract

Standard death certificate-based methods for ascertaining deaths due to chronic liver disease (CLD), such as the U.S. vital statistics approach, rely on a limited set of diagnostic codes to define CLD. These codes do not include viral hepatitis or consider hepatocellular carcinoma (HCC) deaths, and thus, underestimate the true burden of CLD mortality. Deaths associated with CLD may be further misunderstood because of the inherent limitations of death record information. Using a comprehensive list of CLD-related codes to search death records, we investigated the CLD mortality rate and associated etiologies (derived from medical records) in a large managed care health plan. From the 16,970 deaths among health plan members in 2000, we confirmed 355 (2.1%) as CLD related, including 75 with HCC. The age-adjusted CLD mortality rate using the comprehensive codes was 11.9 per 100,000 compared with 6.3 per 100,000 using only conventional codes. Based on medical records, the underlying CLD was attributed to alcoholic liver disease (ALD) in 44% of deaths, HCV infection with ALD in 16%, HCV without ALD in 18%, and chronic HBV infection in 7%. Only 64% of HCV-associated, 48% of HBV-associated, and 64% of ALD-associated deaths ascertained by medical record had that specific etiology mentioned on the death certificate.

Conclusion: CLD mortality burden was almost doubled by using a comprehensive list of mortality codes and considering HCC deaths as CLD related. Furthermore, the contributions of viral hepatitis and ALD to CLD mortality may be underestimated if based solely on death records.