Obesity Linked to Infection after Colon Surgery

With obesity in the national spotlight as a major health problem, many people are now aware that morbid obesity (more than 100 pounds overweight) can directly lead to a number of serious health conditions such as heart disease, high blood pressure and adult-onset diabetes. Far fewer may realize that severe obesity is also linked to a much higher risk of surgical site infection (SSI).

As a bariatric surgeon, I am well aware of the risk of SSI for the severely obese. When performing open bowel surgery on a morbidly obese patient, the infection risk is 20-40 percent. The good news is that we now typically perform the surgery laparoscopically, which reduces the infection risk to only one percent.

I recently read an article, detailed further below, about a study which found that in patients undergoing colon surgery, obesity is associated with a 60 percent increased risk for SSI, with a 14.5 percent infection rate for obese patients versus a 9.5 percent risk for non-obese patients. I concur with the article, and was actually surprised that the infection rates for obese patients weren’t even higher.

The article makes good points in saying that, in addition to the risk of infection, obese patients undergoing colon surgery typically have longer hospital stays and a greater risk of long-term complications such as ventral hernias and stoma complications.

So, should an obese patient try to delay colon surgery until after they’ve had an opportunity to lose weight? For a person 20-40 pounds overweight, I don’t believe it would make that much of a difference. For an individual 100 pounds overweight with a medical condition that doesn’t require immediate surgery, losing weight through bariatric surgery prior to colon surgery would be an option worth exploring.

Delving Deeper

Medscape.com published an article on May 16, 2011, regarding a retrospective study, led by Elizabeth C. Wick, MD, from the Department of Surgery at the Johns Hopkins University School of Medicine (Baltimore, Md.) and colleagues, reported online May 16 in Archives of Surgery.

Article Overview

A new study has found that in patients undergoing colectomy, obesity is associated with a 60 percent increased risk for surgical site infection (SSI), and those developing SSIs had significantly increased costs and longer hospital stays than those who did not.

To evaluate this issue, the researchers designed a retrospective study of patients undergoing colectomy because of the greater risk for SSI with this surgery compared with other abdominal surgeries. The cohort included 7,020 patients undergoing colectomy. The authors reviewed administrative claims data from eight BlueCross BlueShield insurance plans and compared 30-day SSI rates among obese and non-obese patients and determined health care claims in the 90 days after surgery. Patients had undergone complete or segmental colectomy for colon cancer, diverticulitis, or inflammatory bowel disease between Jan. 1, 2002, and Dec. 31, 2008.

Study Results

The overall rate of SSI was 10.3 percent. Obese patients had a significantly higher rate of SSI compared with non-obese patients (14.5 vs. 9.5 percent, respectively; P <.001). Obesity was the strongest predictor of SSI after adjusting for laparoscopy, diagnosis, sex and age. Obese patients experienced a 60 percent increased odds of SSI compared with non-obese patients (odds ratio, 1.59; 95 percent confidence interval, 1.32 – 1.91). Open surgery vs. laparoscopy was also associated with SSI (odds ratio, 1.57; 95 percent confidence interval, 1.25 – 1.97).

Average cost was more than $17,000 higher in patients with SSI ($31,933) compared with the cost for those without infection ($14,608; P <.001). In addition, in patients with SSIs, hospital stays were an average of more than a day longer (mean, 9.5 vs. 8.1 days, respectively; P <.001), and these patients were more likely to be readmitted into hospital (27.8 vs. 6.8 percent, respectively; P <.001).

Summary of Findings:

Obesity was the strongest predictor of SSI after adjusting for laparoscopy, diagnosis, sex and age. Obese patients experienced a 60 percent increased odds of SSI compared with non-obese patients. SSIs increase the cost of care, lengthen hospital stays and increase the likelihood of hospital readmission.

Summary of Commentator Side Statements:

Dr. Wick and colleagues added:

  • SSI rate is now considered to be one of the best measures of quality for surgical procedures. By far, the most common major SSI risk factor encountered is obesity — a condition that is increasing in prevalence and differentially affects certain minority populations.
  • The costs to society of SSIs are far greater can be estimated in this study, as patients with SSIs have delayed return to daily activities after surgery and have increased risk of long-term complications such as ventral hernias and stoma complications.
  • Pay-for-performance policies in surgery should account for the increased risk of infection and cost of caring for this population.

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