2.8% of patients with a Body Mass Index (BMI) of 23.1 die within 30 days of surgery compared to 1% of those with a BMI of 35.3 or more, researchers from the University of Virginia, Charlottesville, reported in Archives of Surgery. Those with a BMI of 23.1 or less were found to be 40% more likely to die within 30 days of surgery than those with a BMI from 26.3 to 29.6 (mid-range BMI).

Put simply: it seems that slim people are more likely to die within a month of surgery than overweight or obese people.

The authors wrote, as background information:

“Recent reports suggest that the prevalence of obesity among U.S. adults has increased more than 100 percent since 1990. This analysis examines the relationship between obesity (as measured by body mass index [BMI; calculated as weight in kilograms divided by height in meters squared]) and surgical mortality.”

Florence E. Turrentine, Ph.D., R.N. and team set out to determine whether a patient’s BMI might be linked to 30-day mortality after surgery. They gathered data from the American College of Surgeons National Surgical Quality Improvement Program, involving 189,533 individuals who had undergone general or vascular surgery in 2005 or 2006 at one of 183 different sites.

Below are some of their findings:

  • 3,245 patients died within 30 days of a surgical procedure; 1.7% of the 189,533 individuals
  • 2.8% of those with a BMI of 23.1 or less died within thirty days
  • 1% of those with a BMI of 35.3 or more died within thirty days
  • Those with a BMI of 23.1 or less were 40% more likely to die within thirty days compared to patients whose BMI was from 26.3 to 29.6
  • 13.9% of those who underwent exploratory Laparotomy died within thirty days – the category with the highest mortality rate
  • 01% of those who had a breast lumpectomy died within thirty days – the category with the lowest mortality rate

They detected a statistically significant interaction between Body Mass Index and the type of procedure, suggesting that the link between BMI and mortality varied for patients who underwent these surgical procedures, including hernia repair, colorectal resection, upper gastrointestinal procedures, musculoskeletal system procedures, wound debridement, and colostomy.

The researchers concluded:

“These results indicate that BMI is a significant predictor of mortality within 30 days of surgery, even after adjusting for the contribution to mortality risk made by type of surgery and for a specific patient’s overall expected risk of death.”

Written by Christian Nordqvist