Overweight and obese people are twice as likely to survive if admitted to hospital for any kind of infectious disease, according to a major new study on the so-called “obesity paradox”.
The study by researchers in Denmark is one of the latest to examine the controversial link between body mass index (BMI) and mortality.
“Overweight and obesity were associated with substantially reduced 90-day mortality”
While being overweight or obese is associated with many different health risks – a growing trend nurses and others are working hard to reduce – there is some evidence it offers protection against infection and other issues that can threaten a patient’s survival.
The Danish study is among a series unveiled at this year’s European Congress on Obesity looking at this interesting relationship.
The study team from Aarhus University Hospital identified more than 35,000 patients admitted to hospital in central Denmark for an infectious disease between 2011 and 2015.
The researchers went on to compare the risk of death within 90 days for different groups including people who were underweight, normal weight, overweight and obese.
The findings showed that people who were underweight were 2.2 times more likely to die than those of a normal weight.
However, there was no real difference if patients classed as underweight had a stable weight – in other words they had not recently experienced a drop in weight that could be the result of other health problems.
“This might be the metabolic protective shield also described as the ‘obesity paradox’”
In contrast, patients who were overweight were found to be 40% less likely to die than people who were a normal weight, while people classed obese were 50% less likely to die.
This was the case even when other factors like smoking, recent weight loss or gain, cancer and other health conditions were taken into account, noted the researchers.
The study findings were presented today at the conference, which is taking place in Vienna from May 23 to 26.
“Overweight and obesity were associated with substantially reduced 90-day mortality following incident hospital admission for infection,” said the research team, which was led by Sigrid Gribsholt.
Meanwhile, a large-scale study looking at data from the US – which was also presented at the same event – found obese and overweight people who had been hospitalised for pneumonia were between 20% and 30% less likely to die than patients with a normal weight.
Researchers from the US and Taiwan examined data on more than 1.7 million cases of pneumonia across 1,000 hospitals in America to look at link between BMI and 30-day mortality rates.
When they looked at cases where patients did not need a ventilator, they found overweight patients were 23% more likely to survive and obese patients were 29% more likely to survive than those of normal weight.
Among those with more serious pneumonia who did need a ventilator, overweight and obese patients were 21% and 30% more likely to live respectively compared with those of normal weight.
The same research team from Taipei Medical University Hospital and the John Peter Smith Hospital in Texas also found overweight and obese patients were less likely to die from sepsis in hospital after 30 days based on data on 3.7 hospital admissions in the US.
Meanwhile, yet another paper – this time by researchers from the Netherlands – has suggested that being obese may be an advantage if a patient needs intensive care.
The study, led by the Erasmus University Medical Centre in Rotterdam, found obese people who were seriously ill may have a better chance of survival because they suffer less muscle wasting.
The snapshot study looked at group of critically ill 26 patients – nine of whom were classed as obese – and used ultrasound to look at muscle quality.
Researchers found the obese group had a higher muscle quality and observed “distinctly different” muscle wasting patterns between obese and non-obese patients. The speed of wasting was also lower in the first four to five days in the obese group.
“Critically ill patients with obesity seem to have higher muscle quality, as measured by ultrasound at the point of admittance to intensive care compared to non-obese patients,” said the researchers.
“This might be the metabolic protective shield also described as the ‘obesity paradox’,” they noted.