健康英语新闻:Underweight patients more likely to die than mildly obese patients

BEIJING, Nov. 22 (Xinhuanet) -- Underweight patients may have more possibilities of mortality within 30 days of general and vascular surgery compared with mildly obese patients, according to a research published online in Archives of Surgery Tuesday.

Researchers at the U.S. National Surgical Quality Improvement Program conducted the research for the years 2005 and 2006, and assessed the contribution of BMI (Body Mass Index) to 189,533 postsurgeries morbidity and mortality by obesity classes.

They found that compared with the middle BMI quintile group, patients with BMI value below 23.1, had greater chances for death. For the highest BMI quintile group, higher mortality rate was also observed.

However, the researchers also found that obesity may as well be associated with increased mortality for some individual types of surgeries.

"These individual types of procedures include procedures with which the general surgeon should have definite experience: colorectal resection, colostomy formation, cholecystectomy, hernia repair, mastectomy, and wound debridement," said George J. Stukenborg, PhD, of the University of Virginia inCharlottesvilleand his colleagues.

Based on a 30 –day morbidity and mortality risk calculation, the sample patients were categorized into BMI quintile ranges. BMI value of less than 23.1 was considered as lowest, values from 26.3 to 29.6 considered as the middle quintile, and above 35.2 considered as the highest.

Factors such as lack of enough data on nonfatal complications and hospital resources, or examining mortality over the 30-day baseline, may cause limitations and inaccuracy to the research and more studies on a wider range of patients in terms of BMI are needed to further confirm the current conclusion, researchers said.