UT Health San Antonio study uncovers key risk factors for diabetic foot infection recurrence

Texas has one of the highest rates of diabetes in the country, with more than 2.7 million Texans diagnosed with the condition. About one in six people in San Antonio have Type 2 diabetes, and a third of residents are prediabetic, according to the American Diabetes Association.

Type 2 diabetes is a chronic condition in which the body cannot produce enough insulin or use insulin properly and, if left uncontrolled, can lead to high blood sugar, heart disease and kidney failure. It also predisposes people to foot ulcers, of which almost 50% become infected, subsequently leading to hospitalization and potentially amputation of part of the foot or a lower limb.

A study published in November 2024 in the International Wound Journal conducted by scientists at The University of Texas Health Science Center at San Antonio (UT Health San Antonio) outlined for the first time the risk factors for reinfection after treatment of a diabetic foot infection. According to the findings, nearly half of patients who receive treatment for diabetic foot infections will experience reinfection. Understanding risk factors of reinfection can guide provider care and produce better patient outcomes.

Lawrence Lavery, DPM, MPH

Leading the study was Lawrence A. Lavery, DPM, MPH, a diabetic foot complications specialist and professor of orthopaedics in the Joe R. and Teresa Lozano Long School of Medicine’s Division of Podiatry. He recently returned to UT Health San Antonio — 30 years after completing his residency at the university and then serving as a faculty member — to conduct research on the high-risk populations of San Antonio and the South Texas region.

What you can’t feel can hurt you

Approximately 50% of patients with diabetes will develop what is called peripheral neuropathy that is severe enough to cause sensory loss in the feet, among other symptoms. Chronically elevated blood glucose, common among diabetics, can damage the nerves of the hands or feet, and this may cause tingling, pain or numbness.

Because people with neuropathy have reduced or absent feeling in their feet, they may not feel a minor cut, blister or callus. These can turn into an open wound and a breakdown of surrounding tissue called an ulcer. Having diabetes can also cause the body to heal more slowly, adding to an increased risk of long-term open wounds and infection.

“When a wound hasn’t healed, that is the doorway for bacteria to get in and cause a second infection,” Lavery said.

For their report, the research team completed a retrospective study of eight years of patient charts and gathered data for 294 patients who had been admitted to the hospital for a moderate to severe diabetic foot infection. Patients were between the ages of 18 to 89, with a median age of 53, and 75% were men. The team then investigated rates of reinfection in the soft tissue or bone of the foot over an additional 12-month period.

Clock starts ticking on unhealed wounds

From their review, the most significant factor in predicting reinfection was the presence of wounds that took three months or longer to heal. Patients in this group were three times more likely to experience reinfection. Additionally, patients with bone infections were more than twice as likely to experience reinfection than patients with soft tissue infections only. Patients whose wounds healed completely had a significantly lower risk of reinfection.

“It’s not related to people not having effective treatment of the first infection. It’s wound healing. When your wound fails to heal or you develop another wound, the clock starts ticking,” Lavery said.

Along with a higher risk of reinfection, patients with unhealed wounds had greater instances of other complications including longer healing time, more foot-related hospital readmission and longer hospital stays. Calling awareness to these risk factors could help stem a cycle of infection, reinfection, amputation, re-amputation, repeat hospitalizations and even early death.

Diabetic foot complications can be emotionally and financially draining for a patient’s entire family, Lavery said. Diabetic men have twice the amputation rate as women, and many are of working age with children at home. He said individuals often face the difficult decision of staying home to heal properly or returning to work to provide for their family, risking a longer recovery and a higher chance of reinfection.

Younger adults face diabetes crisis

Lavery said there is a stark increase in diabetic complications among younger adults in recent years caused, in part, by individuals developing obesity, high blood pressure and other comorbidities earlier than ever.

“It’s not as much the chronological age as the physiological age caused by the burden of disease that is making them ‘older.’ We are getting more and more 30-year-olds in the hospital with foot infections. Usually, people don’t get neuropathy until they’ve had diabetes for a decade. People are getting diabetes younger, and it is increasing the number of people facing limb-threatening infections,” Lavery said.

An eye on prevention

To help prevent diabetic foot infections and other health complications, UT Health San Antonio developed a comprehensive program that includes specialized prevention clinics in San Antonio. According to Lavery, the university is the ideal place to coordinate a framework of multidisciplinary care that incorporates education, preventive care and addressing potential health care barriers.

“This is a call for us to be more aggressive about treating complex wounds so we prevent infection, create better ways to monitor infection and better ways to be proactive about using new technology. It’s a great opportunity to bring evidence-based medicine to the clinic and to the patients and their families,” Lavery said.



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