210393 Seasonality of Viral GI in the US elderly

Wednesday, November 11, 2009: 10:45 AM

Kenneth K. H. Chui, PhD, MS/MPH , Department of Public Health and Community Medicine, Tufts University, Boston, MA
Jeffrey K. Griffiths, MD, MPH & TM , School of Medicine, Tufts University, Boston, MA
Elena Naumova, PhD , Department of Public Health and Community Medicine, Tufts School of Medicine, Boston, MA
Seasonality of viral gastroenteritis has been documented in developing and developed countries. The studies focused primarily on children; data on elderly are lacking. We abstracted hospitalization records from the Centers of Medicare and Medicaid Services, associated with “enteritis due to specified virus” (ICD-9-CM-008.6), infections due to “other organism not elsewhere classified” (ICD008.8), “ill-defined intestinal infections” (ICD009), and “other and unspecified noninfectious gastroenteritis and colitis” (ICD558.9) among patient ≥65 year-old in each state from 1991–2004. Seasonal time to peak was estimated with harmonic regression adapted for Poisson-distributed outcome, presented as daily time series. Of 1.67 millions records of gastrointestinal infections (ICD001–009), 0.31 millions (18.9%) were due to other unclassified organisms, 76,993 cases (4.6%) were due to ill-defined intestinal infections, and only 7,810 cases (0.5%) were due to specified viruses. We found no uniform seasonal pattern in Ill-defined intestinal infections across all states. However, thirty-eight out of 51 states showed significant seasonality in enteritis due to specified virus (ICD008.6). Median time to peak was 56th (IQR: 46th, 77th) calendar day. The south-eastern part of the U.S. viral enteritis peaked the latest. All states showed a significant seasonality in both categories with poorly defined causal pathogens: ICD008.8 (Median & IQR: 33rd, 24th–38th) and ICD558.9 (Median & IQR: 58th, 47th–63rd). Their times to peak, though being three weeks apart, were highly correlated (r=0.57, p<0.001), indicating synchronization of events which are likely to reflect untested and/or undetected causal pathogens. Further study on testing and coding practices for viral infections is recommended.

Learning Objectives:
Describe how seasonal patterns may also be driven by hydrological parameters and water quality.

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: This is work is from my thesis research, which I conceptualized and conducted independently.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.