Obesity may increase risk of death from H1N1

Researchers recently found that extreme obesity can increase patients’ risk of death from the H1N1 influenza virus.

The California Department of Public Health and the California Pandemic (H1N1) Working Group collected data on 534 adult patients who were hospitalized for H1N1 infections in 2009. Of the 92 patients who died, 61% had body mass indexes (BMIs) of 30 or more, and 30% had BMIs of 40 or more.

“This is one of the first studies to identify extreme obesity as a risk factor for severe influenza infection (in this case, 2009 H1N1 influenza). The Advisory Committee on Immunization Practices recommendations developed in 2010 suggested that persons with extreme obesity should be vaccinated annually, because of their increased risk,” said Janice Louie, MD, MPH, lead author of the study and chief of the Surveillance and Epidemiology Section, Communicable Disease and Emergency Response Branch, California Department of Public Health.

Many of both the fatal and nonfatal cases of H1N1 that the researchers studied had other medical conditions such as heart failure or kidney infection. “However, when we performed complex statistical analysis to account for all of those different underlying medical illnesses, extreme obesity with a BMI equal to or more than 40 still stood out as a risk factor for death, independent of those other illnesses,” Dr. Louie said.

Dr. Louie recommends that extremely obese individuals see their healthcare provider early, when it is known that influenza is circulating, to get the appropriate testing and antiviral medications, if needed.

The findings will be published in the February 1 issue of Clinical Infectious Diseases.