Australians consume an average of 60 grams —or 14 teaspoons — of sugar per day. But, if you are a diabetic, too much sugar in your blood can lead to diabetic foot ulcers, foot amputations, and a higher mortality rate. For her PhD thesis, Dr Chanika Alahakoon from the Australian Institute of Tropical Health and Medicine (AITHM) worked with patients admitted to the Townsville University Hospital for diabetic foot ulcers with the aim to prevent future hospital readmissions.
Sugar is an important energy source for the body. But at the same time, too much sugar in the blood can cause severe damage. “When you have high levels of sugars, there's a process called ‘glycation’ that happens in your blood,” Dr Alahakoon said. “This means that sugar attaches itself, for instance, to haemoglobin — the red colour pigment in your red blood cells — or to other proteins and cell membranes. This can lead to a variety of problems.
“In a healthy person, glycation of haemoglobin should be kept at less than six per cent. However, if you're diabetic, it is recommended to keep it under seven per cent,” she said. “In those who have diabetic foot ulcers, we see nine or ten per cent persistently. This indicates that other protein substances are being subjected to the same glycation process.”
People will often feel the effects of high blood sugar in their hands and feet first. “This sensory loss is known as the glove and stocking pattern,” Dr Alahakoon said. “If people then sustain injuries, they don’t feel the pain. When this happens repeatedly, people can get deformed feet or a ‘diabetic foot’, for example. This could be a little ulcer that just doesn’t heal and can become infected because the white bloods cells cannot get to the infection site.”
For her PhD research, Dr Alahakoon and AITHM Distinguished Professor Jonathan Golledge worked with 190 patients who had been admitted to the Townsville University Hospital for diabetic foot disease. “The patients received the usual treatments such as antibiotics and treatments to restore blood flow,” Dr Alahakoon said. Some patients were also fitted with a ‘total contact casting’, which is similar to a regular plaster cast. “A total contact casting distributes the pressure on the foot evenly and gives the ulcer time to heal.”
Even though a total contact casting contributes to the healing process, foot ulcers will return if the patients don’t change their diet and take better care of their feet. More than half of the patients in Dr Alahakoon’s study were readmitted within 12 months. “The main reason for readmission was a subsequent diabetes-related foot problem,” she said.
This is why Dr Alahakoon examined how recurrent diabetes-related foot ulcers could be prevented in the first place. “Patient education was favoured by other researchers because it does carry some weight if you tell patients, ‘don't do this’ and ‘don't do that’,” Dr Alahakoon said. “Regular GP visits are important, too. But overall, in our meta-analysis, we found that telling patients not to walk barefoot or not to wear thin-soled shoes or, generally, to take better care of their feet is not very effective,” she said.
However, there are other methods to prevent foot ulcers. “We looked at foot temperature monitoring with an infrared thermometer, which patients can do at home,” Dr Alahakoon said. “The studies we analysed show that it was easier to predict a foot ulcer in patients who measured their foot temperature every day.”
Thermometers can show signs of inflammation, as an inflamed foot is indeed hotter than a foot that is not affected. “The idea was if you can measure the temperature, if you find it to be higher than the opposite leg and seek help from your podiatrist or doctor quickly, they will be able to help before things worsen.”
Podiatrists can, among other things, measure the patient’s foot and order custom-made shoes that perfectly fit the shape of the foot. “We call this ‘offloading footwear,’ as it evenly distributes pressure on the foot. It’s just like a total contact casting, but definitely more comfortable,” Dr Alahakoon said.
Dr Alahakoon was awarded a Medal for Excellence for her PhD thesis, Burden of Diabetes-Related Foot Disease in North Queensland, Australia, which was recognised as making a significant contribution to the future wellbeing of people suffering from diabetic foot disease.
Supported by a Medical Research Future Fund (MRFF) Cardiovascular Health Mission grant, Dr Alahakoon and Professor Golledge are now examining ways to prevent peripheral artery disease (reduced blood flow to the arms or legs) in diabetes patients.