乌鸦传媒

In patients with type 2 diabetes undergoing surgery, metformin appeared to offer some protection against poor outcomes, researchers reported.

In an analysis of 10,088 adults with diabetes undergoing a major surgical intervention, those with a prescription for metformin prior to surgery saw a 27% lower risk for 90-day mortality (adjusted hazard ratio 0.72, 95% CI 0.55-0.95, P=0.02), relative to patients not on presurgical metformin, according to Katherine Reitz, MD, of the University of Pittsburgh School of Medicine, and colleagues.

Their study, online in , also found lower risk of 5-year mortality with metformin taken before surgery (HR 0.74, 95% CI 0.65-0.85, P<0.001). However, preoperative metformin prescriptions didn't have any significant association on 30-day mortality rates (HR 0.91, 95% CI 0.61-1.34, P=0.62).

Readmission rates were lower as well in the metformin group (HR at 30 days 0.84, 95% CI 0.72-0.98; HR at 90 days 0.86, 95% CI 0.77-0.97).

"Metformin is actively being explored as both a preventative medication and treatment for numerous diseases in both diabetic and non-diabetic patients," Reitz told 乌鸦传媒. "These studies have shown promising results, and we were hopeful that metformin would be effective for our surgical patients." She added that the researchers were "very surprised by both the magnitude and the strength of the positive effect associated with metformin therapy."

"If we conservatively estimate that 20 million major surgeries occur annually in the United States, our data would suggest metformin may help to reduce readmissions for 200,000 Americans and prolong the life of 10,000 each year," Reitz said.

She noted that these surgical outcomes may be related to the in patients with diabetes, as recent data have indicated.

The retrospective cohort analysis assessed adults with diabetes who underwent a major operation at one of 15 community and academic hospitals in a single hospital system from 2010 to 2016. A major operation was defined as one requiring both general anesthesia and postoperative hospital admission. Among the 10,088 adults with diabetes included, 5,962 (59%) had a preoperative metformin prescription, defined as one or more prescriptions for metformin within the 180 days prior to the procedure. A total of 5,460 of these patients with metformin prescriptions were propensity score matched to surgical diabetes patients without metformin exposure.

"Metformin now joins β-blockers, statins, and immunonutrition as preoperative agents associated with improved surgical outcomes," wrote the authors of an . "It may be only a matter of time before optimization of postoperative outcomes with perioperative medications and supplements becomes a standard," said Elizabeth George, MD, and Sherry Wren, MD, both of Stanford University School of Medicine in California.

They explained that metformin is usually held following surgery -- unlike statins -- due to its potential interaction with contrast agents. But both drug types "are postulated to be mediated through anti-inflammatory and immunomodulatory properties."

A study limitation, George and Wren said, was that there was no adjustment for statin use, since more than half of the patients included were on a statin either before or after surgery. Future studies, therefore, the commentators said, should either exclude patients taking statins or investigate possible interactions in the model between the two agents.

"We would be interested in seeing a subanalysis of this data set that excludes patients who were prescribed statins," the commentators concluded, noting that such data could further strengthen metformin's role as a potentially new modifiable perioperative factor.

Reitz also noted that the findings have been the impetus for a currently underway at the University of Pittsburgh Medical Center assessing the association of surgical outcomes and metformin use. The trial will assess low, intermediate, and high doses of metformin given for various durations.

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