The Roles of Clostridium difficile and Norovirus among Gastroenteritis-Associated Deaths in the United States, 1999–2007

The Roles of Clostridium difficile and Norovirus among Gastroenteritis-Associated Deaths in the United States, 1999–2007

1. Aron J. Hall1,
2. Aaron T. Curns1,
3. L. Clifford McDonald2,
4. Umesh D. Parashar1, and
5. Ben A. Lopman1

+ Author Affiliations

1. ¹Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
2. ²Division of Healthcare Quality Promotion, National Center for Emerging and Zoonotic Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia

1. Reprints or correspondence: Dr. Aron J. Hall, Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA 30333; phone: 404-639-1896 ; fax: 404-639-8665; email: ajhall@cdc.gov.

Gastroenteritis-associated mortality has more than doubled over the past decade, primarily impacting the elderly. C. difficile is the main contributor to gastroenteritis-associated deaths, largely accounting for the increasing trend, while norovirus is likely the second leading infectious cause.

Abstract

Background Globally, gastroenteritis is recognized as an important contributor to mortality among children, but population-based data on gastroenteritis deaths among adults and the contributions of specific pathogens are limited. We aimed to describe trends in gastroenteritis deaths across all ages in the United States and specifically estimate the contributions of Clostridium difficile and norovirus.

Methods Gastroenteritis-associated deaths in the United States during 1999–2007 were identified from the National Center for Health Statistics multiple cause-of-death mortality data. All deaths in which the underlying cause or any of the contributing causes listed gastroenteritis were included. Time-series regression models were used to identify cause-unspecified gastroenteritis deaths that were likely due to specific causes; seasonality of model residuals was analyzed to estimate norovirus-associated deaths.

Results Gastroenteritis mortality averaged 39/1,000,000 person-years (11,255 deaths/year) over the study period, increasing from 25/1,000,000 person-years in 1999–00 to 57/1,000,000 person-years in 2006–07 (P<0.001). Adults aged ≥65 years accounted for 83% of gastroenteritis deaths (258/1,000,000 person-years). C. difficile mortality increased 5-fold from 10/1,000,000 person-years in 1999-00 to 48/1,000,000 person-years in 2006-07 (P <.001). Norovirus contributed to an estimated 797 deaths annually (3/1,000,000 person-years), with surges by up to 50% during epidemic seasons associated with emergent viral strains.

Conclusion Gastroenteritis-associated mortality has more than doubled over the past decade, primarily impacting the elderly. C. difficile is the main contributor to gastroenteritis-associated deaths, largely accounting for the increasing trend, while norovirus is likely the second leading infectious cause. These findings can help guide appropriate clinical management strategies and vaccine development.

• Received December 28, 2011.
• Revision received March 5, 2012.
• Accepted March 13, 2012.

• Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2012.