Do diabetics do better after colon cancer surgery?

People with diabetes actually fare better after colon cancer surgery than people without the condition, according to surprising new findings published in the Journal of General Internal Medicine.

"We were really expecting to find the opposite," Dr. Geoffrey C. Nguyen of the University of Toronto, the lead researcher on the study, told Reuters Health.

Nguyen and his team looked at records for nearly 220,000 people who had colon cancer surgery at US hospitals between 1995 and 2005. Eighty-five percent didn't have diabetes, 14 percent had uncomplicated diabetes - meaning they didn't have diabetes-related problems like kidney disease or vision loss - and 1 percent had complicated diabetes.

While 3.2 percent of the non-diabetic patients died in the hospital after surgery, 2.5 percent of those with diabetes did. The difference only appeared among patients with uncomplicated diabetes, 2.4 percent of whom died, compared to 4.2 percent of the patients with complicated diabetes.

This translated to a 29 percent lower risk of death among patients with uncomplicated diabetes.

Twenty eight percent of patients with uncomplicated diabetes had complications related to surgery, for example an infection, compared to 31 percent of non-diabetics, giving them an 18 percent lower risk.

When the researchers analyzed subgroups of the patients, they found differences in survival and complication rates between non-diabetics and uncomplicated diabetics only appeared in patients older than 50, and among those who had health insurance.

Both these findings indirectly support the hypothesis that extra attention-known medically as perioperative care-was what made the difference for diabetics, Nguyen said. In other words, patients with insurance might have had access to better care, and doctors are more likely to be more vigilant in older patients.

"The doctors may be keeping a better eye on you," he explained.

There are a number of limitations of the current study, Nguyen noted, such as the fact that the data used came from hospital claims, rather than being gathered by researchers who could ensure that people were classified adequately.

"At this point, this is meant to stimulate further research," he added. If it did turn out that perioperative care was the factor that helped diabetic patients do better, he said, the findings could have much wider implications.

But for now, Nguyen concluded, "I don't think we can go out and say that everyone should go out and get perioperative care."

SOURCE: Journal of General Internal Medicine, online March 30, 2010.