If you’re anything like me, when you hear “diabetic foot ulcers”, it doesn’t really hit home. You know what all of those words mean individually. You understand diabetes. You know what an ulcer is. You have a general idea that we’re dealing with something pretty uncomfortable. But then you Google image search “diabetic foot ulcers,” and the graphic pictures of the chronic open wounds found at the bottom of the foot is far more visceral than anything you were picturing in your head.
At this point, I should probably give you time to actually check this for yourself. Go ahead. Google it. I’ll wait here.
Pretty gruesome, right?
But go beyond the harsh reality of the wound itself. The American Diabetes Association estimates that 15 percent of patients who develop diabetic foot ulcers will need to have some type of lower limb amputation as a result. These ulcers can double the risk of death compared to the risk associated with diabetes alone. A staggering 45 to 55 percent of diabetic foot ulcer patients will die within five years.
“The mortality rate associated with diabetic foot ulcers is higher than the rate for Hodgkin’s lymphoma, breast cancer, or prostate cancer, which really puts this into context,” said Elizabeth Grice, PhD, a researcher and assistant professor in the department of Dermatology at the Perelman School of Medicine.
But diabetic foot ulcers don’t just double the risk. They can also double the cost of care. A recent study published by the American Diabetes Association found ulcer care adds between $9 billion and $13 billion dollars to the yearly costs associated with diabetes itself.
The high-stakes health risks and cumbersome costs make treating diabetic foot ulcers a top priority. And two new pieces of research from Grice and her team are adding to our understanding of what makes the wounds so uniquely challenging. Together, these studies are looking at what goes on inside these wounds in a way no one has before. According to Grice, putting the two studies together could be the first step in getting the full picture when it comes to treating these devastating and costly chronic wounds. Turns out it’s all about the fungi and bacteria.
The first study, led by post-doctoral researcher Lindsay Kalan, PhD, followed 100 patients with diabetic foot ulcers for 26 weeks, or until the wound healed or required amputation. Participants all received the same medical care, which included having their deep wound fluid sampled every two weeks. When Grice’s team analyzed the samples, they found 80 percent of them contained fungi – a stunning number much higher than previous estimates. They found 284 different species of fungi overall. The most common type was Cladosporium herbarum, which showed up in 41 percent of the samples.
“Other studies have looked at wounds at one point in time, which only provides a cross-section,” Grice said. “Our approach of following the patients over a period of time gives us a more precise readout of how microbial communities fluctuate and how they are linked to outcomes.”
The study found fungi were able to get a stronger foothold in wounds with high levels of dead tissue, which could lead to more complications. Additionally, the team showed that fungal pathogens closely interact with and form structures with bacterial pathogens co-isolated from the wounds.
The second study dealt with microbiota – tiny organisms living in the wound itself. That research, led by Michael Loesche, and MD/PhD candidate at the Perelman School of Medicine, tried to find the correlation between bacteria colonization and healing, as well as potential complications. The team used the same process as in the first study, following 100 patients for 26 weeks, or until the wound healed or required amputation.
“Past studies on this question have been limited because they’ve only looked at the wound at one point in time,” Grice said. “This is, we believe, the largest group ever continuously sampled with outcome data included.”
Grice‘s team found the more a stable community of microbiota were in a wound, the harder it was for the wound to heal.
“That stability may be indicative of the microbes shifting into a biofilm state, where they are more difficult to treat and remove,” Grice said.
Grice said the next steps are to more precisely determine how the microbes are impairing healing and to analyze the impact they could be having on patient outcomes.