Hepatitis A hospitalizations in the United States, 2002-2011

Hepatitis A illness severity increases with age. One indicator of hepatitis A illness severity is whether persons are hospitalized. We describe changes in primary hepatitis A hospitalization rates in the United States from 2002-2011, including changes in demographics, secondary discharge diagnoses, and factors affecting hospitalization duration. We describe changes from 2002-2011 among U.S. residents hospitalized with a principal hepatitis A diagnosis and accompanying secondary diagnoses using ICD-9 codes from the National Inpatient Survey discharge data. We calculated rates of hospitalizations with hepatitis A as the principal discharge diagnosis and rates of secondary discharge diagnoses. Using multiple regression, we assessed the effect of secondary diagnoses on hospitalization length of stay for five time intervals: 2002-2003, 2004-2005, 2006-2007, 2008-2009, and 2010-2011. Rates of hospitalization for hepatitis A as a principal diagnosis decreased from 0.72/100,000 to 0.29/100,000 (P < 0.0001) and mean age of those hospitalized increased from 37.6 years to 45.5 years (P < 0.0001) during 2002-2011. The percentage of hepatitis A hospitalizations covered by Medicare increased from 12.4% to 22.7% (P < 0.0001). Secondary comorbid discharge diagnoses increased, including liver disease, hypertension, ischemic heart disease, disorders of lipid metabolism, and chronic kidney disease. No changes in length-of-stay or in-hospital deaths from hepatitis A over time were found, but persons with liver disease were hospitalized longer.

Hospitalization rates for hepatitis A illness have declined significantly from 2002-2011, but the characteristics of the hospitalized population also changed. Persons hospitalized for hepatitis A in recent years are older and more likely to have liver diseases and other comorbid medical conditions. Hepatitis A disease and resulting hospitalizations could be prevented through adult vaccination.