Introduction
Diabetes mellitus, one of the most common chronic metabolic diseases worldwide, is characterized by high blood sugar and leads to many serious complications.1 The complications caused by long-term high blood glucose include nephropathy, retinopathy and neurovascular complications.2 One of the most serious conditions of diabetes-related neurovascular complications is foot ulcers. It was estimated that approximately 15% of people with type 2 diabetes would be affected by foot ulcers.3 However, in 2015, the International Diabetes Federation reported that this rate was approximately 34%.4 Diabetic foot ulcers lead to amputation at various levels, depending on severity, in approximately 20% of patients. Furthermore, diabetic foot ulcers increase the risk of death. Patients with diabetic foot ulcers have a 2.5-fold higher risk of death at 5 years than those without diabetic foot ulcers.5 Unfortunately, despite significant improvements in diabetic foot care and treatment, the rate of amputation due to diabetic foot ulcers is increasing.
One of the classifications of diabetic foot ulcers was developed by Wagner in the 1970s, in which ulcers were graded between 0-5. In this classification, only the depth of the ulcer, osteomyelitis and gangrene are evaluated, but the presence of ischemia is not considered.6, 7, New classification systems have been developed after this classification; however, the Wagner classification is simple and very effective in predicting low extremity amputation.8, 9 Ischemia in tissues due to the decreased blood flow in diabetic foot ulcers is not considered in the Wagner classification, making it difficult to determine the level of amputation. Therefore, a biomarker to help determine the level of ischemia in these patients may be more effective in determining the degree of amputation. Classical blood parameters such as the erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), procalcitonin and white blood cells (WBC) are used to determine the severity of infection in diabetic foot ulcers. However, there is no blood biomarker to determine the level of ischemia in diabetic foot ulcer.10
Ischemia-modified albumin (IMA) is a structure formed by the change of the N-terminal end as a result of ischemic damage of circulating albumin; due to this modification, the transport of elements such as cobalt and nickel is impaired.11 In recent years, many studies have been reported on whether IMA may be a novel predictor in ischemic injury-related diseases such as stroke, acute mesenteric ischemia, acute pulmonary embolism and coronary syndrome.12 In previous studies, IMA levels were examined for diabetes and diabetes-related complications such as diabetic nephropathy and diabetic ketoacidosis.13 It has also been reported that IMA may be an indicator of diabetes-related complications.14 In the literature review we conducted, we found only one study that examined IMA levels in diabetic foot patients, but there is no study examining the relationship of IMA levels with the Wagner classification in these patients.15
In this study, we aimed to compare IMA levels in diabetic foot patients and a healthy control group. In addition, we aimed to determine the relationship of IMA levels with diabetic foot severity by grouping diabetic foot patients according to the Wagner classification.