Obese patients more likely to survive infection in hospital

Obesity can shorten lives, but obese people who are hospitalised for infectious diseases, pneumonia and sepsis have a better chance of surviving than those who are of normal weight, according to new research.

The so-called “obesity paradox” was illustrated by three separate presentations at the European Congress on Obesity in Vienna. A study of more than 18,000 people admitted to hospital with an infectious disease in Denmark found those who were overweight were 40% less likely to die, and those who were obese 50% less likely to die, than those of normal weight.

A second study using data from 1.7m hospital admissions for pneumonia in the United States in 2013 to 2014 found that overweight patients were 23% more likely to survive and obese patients 29% more likely to survive than those of normal weight.

Other data from the US in patients with sepsis – blood poisoning – found a similar pattern. In more than three million hospital admissions, overweight patients were 23% less likely to die and obese patients 22% less likely to die than those of normal weight.

Sigrid Gribsholt from Aarhus University hospital department of clinical epidemiology in Denmark led the research in the first study, on people admitted with infectious diseases during 2011-2015 in the Central Denmark Region. They looked at the risk of death within 90 days of entering hospital and made allowances for people who smoked or had other medical conditions.

Gribsholt said there were two reasons obese people might be more likely to survive. One is that obesity causes inflammation which invokes a strong response from the immune system – which could help people recover from infection. The second is that people who are obese are less likely to experience wasting as a result of their disease. “They have larger energy reserves, which may also be protective,” she said.