In a study that included more than 300 Medicare-certified nursing homes, rates of hospitalization and death substantially increased during outbreaks of norovirus gastroenteritis compared with non-outbreak periods.
The researchers found that nursing homes with lower daily RN hours per resident had a significantly increased rate of mortality during norovirus outbreaks compared with baseline, while no increased risk was observed in homes with higher daily RN hours per resident.
In background information for the study, which is scheduled for publication in the Oct. 24-31 issue of the Journal of the American Medical Association, researchers noted that more than 1,000 outbreaks of acute gastroenteritis a year are reported by nursing homes to U.S. public health agencies. "This likely represents only a fraction of the actual number due to underreporting."
"Although nearly half of all reported nursing home gastroenteritis outbreaks are never etiologically confirmed because of challenges in performing diagnostic testing, norovirus is implicated in 86% of etiologically confirmed outbreaks," the researchers added. Because hospitalizations and deaths are common among nursing home patients, it has been difficult to ascertain whether a greater number of those events take place during norovirus outbreaks.
Tarak K. Trivedi, BS, a fourth-year medical student at the University of Chicago Pritzker School of Medicine, and colleagues conducted a study to assess the association between norovirus outbreaks and excess all-cause hospitalization and mortality in nursing homes. The study included 308 Medicare-certified nursing homes in Oregon, Wisconsin and Pennsylvania that reported at least one confirmed or suspected norovirus outbreak to the Centers for Disease Control and Prevention’s National Outbreak Reporting System between January 2009 and December 2010.
The nursing homes in the study reported a total of 407 norovirus outbreaks, with a median duration of 13 days. Nursing homes experienced 2,533 hospitalizations (124 per home-year) and 1,097 deaths (53.7 per home-year) during outbreak periods compared with 65,197 hospitalizations (109.5 per home-year) and 24,958 deaths (41.9 per home-year) during non-outbreak periods. After adjusting for seasonality by month, the rates of hospitalization and death were significantly elevated during outbreak periods.
Relative to outbreak onset, the increase in hospitalizations was concentrated in the initial week and the subsequent week, and the increased mortality rate was concentrated in the initial week. In subsequent weeks, the rates of hospitalizations and deaths returned to the levels observed in non-outbreak periods.
"In conclusion, we detected a consistently increased risk of hospitalization and death from all causes during norovirus outbreaks among residents in nursing homes from three U.S. states," the researchers wrote. "As a next step, research should be directed to determine if this increase is directly attributable to norovirus infection and subsequent disease resulting from gastroenteritis.
"At present, strategies for averting these severe outcomes include general treatment for dehydration and infection control to prevent and control outbreaks. More targeted interventions would be welcome and in light of recent progress with a norovirus vaccine, these results highlight a setting and population that may benefit if efficacy and safety of immunization can be demonstrated."
The study appeared on the JAMA website Oct. 18 in conjunction with presentation at the IDWeek 2012 conference in San Diego, and is available at http://jama.jamanetwork.com/article.aspx?articleid=1380392.
The researchers found that nursing homes with lower daily RN hours per resident had a significantly increased rate of mortality during norovirus outbreaks compared with baseline, while no increased risk was observed in homes with higher daily RN hours per resident.
In background information for the study, which is scheduled for publication in the Oct. 24-31 issue of the Journal of the American Medical Association, researchers noted that more than 1,000 outbreaks of acute gastroenteritis a year are reported by nursing homes to U.S. public health agencies. "This likely represents only a fraction of the actual number due to underreporting."
"Although nearly half of all reported nursing home gastroenteritis outbreaks are never etiologically confirmed because of challenges in performing diagnostic testing, norovirus is implicated in 86% of etiologically confirmed outbreaks," the researchers added. Because hospitalizations and deaths are common among nursing home patients, it has been difficult to ascertain whether a greater number of those events take place during norovirus outbreaks.
Tarak K. Trivedi, BS, a fourth-year medical student at the University of Chicago Pritzker School of Medicine, and colleagues conducted a study to assess the association between norovirus outbreaks and excess all-cause hospitalization and mortality in nursing homes. The study included 308 Medicare-certified nursing homes in Oregon, Wisconsin and Pennsylvania that reported at least one confirmed or suspected norovirus outbreak to the Centers for Disease Control and Prevention’s National Outbreak Reporting System between January 2009 and December 2010.
The nursing homes in the study reported a total of 407 norovirus outbreaks, with a median duration of 13 days. Nursing homes experienced 2,533 hospitalizations (124 per home-year) and 1,097 deaths (53.7 per home-year) during outbreak periods compared with 65,197 hospitalizations (109.5 per home-year) and 24,958 deaths (41.9 per home-year) during non-outbreak periods. After adjusting for seasonality by month, the rates of hospitalization and death were significantly elevated during outbreak periods.
Relative to outbreak onset, the increase in hospitalizations was concentrated in the initial week and the subsequent week, and the increased mortality rate was concentrated in the initial week. In subsequent weeks, the rates of hospitalizations and deaths returned to the levels observed in non-outbreak periods.
"In conclusion, we detected a consistently increased risk of hospitalization and death from all causes during norovirus outbreaks among residents in nursing homes from three U.S. states," the researchers wrote. "As a next step, research should be directed to determine if this increase is directly attributable to norovirus infection and subsequent disease resulting from gastroenteritis.
"At present, strategies for averting these severe outcomes include general treatment for dehydration and infection control to prevent and control outbreaks. More targeted interventions would be welcome and in light of recent progress with a norovirus vaccine, these results highlight a setting and population that may benefit if efficacy and safety of immunization can be demonstrated."
The study appeared on the JAMA website Oct. 18 in conjunction with presentation at the IDWeek 2012 conference in San Diego, and is available at http://jama.jamanetwork.com/article.aspx?articleid=1380392.
Send comments to editor@nurse.com or post comments below.
