Infectious disease hospitalizations in the United States.

BACKGROUND: Infectious diseases (IDs) cause widespread morbidity and mortality. We describe the epidemiology of ID hospitalizations in the United States with use of a nationally representative database.
METHODS: First-listed ID hospitalizations in the United States were analyzed using the Nationwide Inpatient Sample for 1998-2006. Hospitalization rates were calculated overall for IDs and for specific ID groups.
RESULTS: An estimated 40,085,978 (standard error, 255,418) hospitalizations with a first-listed ID occurred during 1998-2006, for an age-adjusted hospitalization rate of 154.4 (95% confidence interval, 153.3-155.5) hospitalizations per 10,000 persons. The rate increased slightly over the study period (152.5 [95% confidence interval, 149.6-155.4] in 1998 vs 162.2 [95% confidence interval, 158.7-165.5] in 2006); an increase was seen for both sexes, for older patients, and for Hispanic patients. Among those aged 5-39 years, female patients had a significantly higher hospitalization rate than did male patients; male patients had higher rates among the youngest children and adults aged > or = 40 years. Approximately 4.5 million hospital days and $865 billion in hospital charges were associated with primary ID hospitalizations over the study period. Lower respiratory tract infections were the most commonly listed ID (34.4%), followed by kidney, urinary tract, and bladder infections; cellulitis; and abdominal and rectal infections.
CONCLUSIONS: The ID hospitalization rate increased during 1998-2006, reflecting an increase in ID hospitalizations among adults aged > or = 30 years, particularly older adults. Differences in trends and patterns of ID hospitalizations were noted by sex, age group, and race. Lower respiratory tract infections accounted for the largest proportion of ID hospitalizations. Future efforts should focus on preventive measures and improving early interventions for IDs.