INTRODUCTION
Diabetes mellitus (DM) is one of the largest global health challenges of this century. The International Diabetes Federation estimates that there are 415 million people with diabetes in 2015 and is predicted to increase to 642 million by 2040, worldwide. However, more than 47% of the world’s population may still be undiagnosed for diabetes. Further, it has been noted that the majority of individuals suffering from type 2 diabetes, live in low- and middle-income countries, and among them, India stands second in prevalence.[1]
As a result of the dramatic increase in the worldwide prevalence of DM, a rise in diabetes-related complications is inevitable. Diabetic foot ulcer (DFU) is one of the chronic complications of DM and has significant effects on the patient’s quality of life. The prevalence of DFU ranges from 4% to 10% among hospitalized patients.[2–4]
Foot ulcers precede about 85% of diabetes-related amputations and it leads to more than half of nontraumatic lower limb amputations.[5] The diabetic foot is biologically compromised due to multiple contributing factors, predominantly peripheral neuropathy and ischemia from peripheral vascular disease (PVD). In addition, in the presence of these, moderate ischemia can cause ulcers and impair ulcer healing. The development of DFUs is also associated with multiple risk factors including gender (male), duration of diabetes longer than 10 years, advanced age of patients, foot deformity, high plantar pressure infections, and inappropriate foot self-care habits.
DFU is categorized as neuropathic ulcer (NPU) or neuroischemic ulcer (NIU), which differ in treatment and prognosis.[6–9] In the present study, authors have tried to assess the prevalence of peripheral neuropathy and ischemia in patients with type 2 DM (T2DM) presenting with foot ulcers, in addition to study their clinic-demographic profile and management.
Multiple factors have been postulated for the occurrence of infection and ulceration that lead to amputation. These include walking barefoot, illiteracy, low-socioeconomic status, late presentation, ignorance about diabetic foot care among primary care physicians, and belief in alternative systems of medicine.[9–11]
METHODS
The present study is a descriptive observational study, conducted over 19 months from January 2021 to July 2022. The study included 170 patients, presenting with foot ulcers and concomitantly suffering from T2DM at our center situated in South India. Nondiabetic patients with foot ulcers were excluded from the study.
The variable, DFU was defined by the break of skin continuity in any region below the ankle of any depth level with or without complications in people affected with diabetes; it also included gangrene and necrosis.
Foot ulcers were categorized as ischemic ulcers when peripheral pulses were absent with normal sensation, NPU when the sensation was absent with normal peripheral pulse, and neuroischemic when both sensation and peripheral pulses were absent.
Neuropathy was defined as inability of the patient to detect 10 g nylon monofilament on more than one site or vibration perception threshold of more than 25 V. Vibration perception threshold was measured using biothesiometry and plantar pressure measurements using Podiascan and pediograph. Examination of the foot, peripheral pulses, and blood pressure was done. Absent pulses were defined as the absence of both posterior tibial artery and dorsalis pedis artery pulses in the affected foot. PVD was defined by the Ankle Brachial Blood Pressure Index (ABI) ≤0.90.[12]
The mode of management including diabetic footwear, medical management, revascularization, and need for amputation on follow-up was noted.
RESULTS
Our study population predominantly consisted of elderly males with a mean age of 63.2 years and 71.7% males. Out of 170 patients presenting with DFU, NIUs were diagnosed in 35 patients, and the rest 135 patients were diagnosed to have NPUs [Graph 1]. NIU was observed more common among male patients with 25 males out of 35 patients (71.4%), similarly, NPU was more common in males (72.8%).
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Graph 1: Incidence of NPU and NIU in DFU. NPU: Neuropathic ulcer, NIU: Neuro-ischemic ulcer, DFU: Diabetic foot ulcer
Among the 35 patients who were diagnosed to have NIU, all required diabetic footwear; however, 10 patients required revascularization procedure, two patients required prostaglandin therapy infusion, and one patient required stem-cell implantation. The group of patients, who were diagnosed to have NPUs, required only diabetic footwear and medical therapy which involved antibiotics, antiplatelets, vasodilators, and prostaglandin infusion.
Amputation was required in 8 (23%) out of 35 patients suffering from NIU and in 12 (9%) out of 135 patients suffering from NPU.
DISCUSSION
Based on the WHO criteria, diabetic foot is defined as infection, ulceration, and/or destruction of deeper tissues associated with neurological abnormalities and various degrees of PVDs of the lower limb.[13] DFU is one of the most seriously debilitating complications of diabetes. Of all nontraumatic amputations, approximately 50% are performed on diabetics for complications of the diabetic foot such as nonhealing ulcers and gangrene. PVD is a common association in patients with T2DM. Around 14% of the patients with T2DM in Western countries suffer from PVD, but in India, these figures vary may from 4% to 15%.[14,15] Peripheral atherosclerosis observed in patients with DM is typically more distal in distribution and often more extensive. The distal popliteal, tibial, and metatarsal vessels of lower limbs are most commonly and severely affected.[16] The three main factors leading to diabetic foot ulceration – neuropathy, microangiopathy, and large vessel disease – gives rise to a similar array of abnormalities of microvascular function-limited vasodilatory reserve, impaired postural vasoconstriction, impaired pressure regulation, and maldistribution of blood flow.[17]
Peripheral pulse examination should be done in all patients with DM and ABI should also be measured in addition to clinical evaluation in patients presenting with DFU. Patients should be advised evaluation of leg vessels by peripheral Doppler study and or peripheral angiography when ABI is less than 0.9.
Retrospective and prospective studies have proven that elevated plantar pressure as an important cause of the development of plantar ulcers in diabetic patients[18–20] and that ulceration is often a precursor of lower extremity amputation.[21] Structural abnormalities in the foot have been associated with increased levels of plantar pressure, moreover, in individuals with diabetes, claw toe deformity and Charcot neuroarthropathy are among the most important abnormalities that may cause significant disruption to the architecture of the foot.[22–26] The combination of foot deformity, loss of protective sensation, and inadequate off-loading leads to tissue damage and ulceration. Once an ulcer has formed, studies described below indicate that unless the ulcerated area is off-loaded, healing may be chronically delayed, even in an adequately perfused limb. After an ulcer is healed, the risk of recurrence is high – 40% in a median of 4 months in one recent study[27] – showing the need for continuous off-loading in these patients in the prevention of ulcer recurrence. There is not yet sufficient evidence to support the primary prevention of ulcers by off-loading, although clinical opinion strongly favors such an approach. Many new potential solutions for healing DFUs – such as topically applied growth factors, bioengineered skin, and stem cells have been proposed. What all solutions have in common is that they require a mechanical environment that will not destroy the healing construct. This must be achieved by some device that will effectively remove mechanical stress from the wound and its immediate environment. The effectiveness of off-loading must be judged both by the relief of stress and by the patient’s adherence to the treatment.
A multidisciplinary approach is required for DFU involving a diabetologist, podiatrist, vascular surgeon, plastic reconstructive surgeon, and rehabilitation physicians.
CONCLUSION
DFU is a very debilitating complication of diabetes and a leading cause of amputation worldwide. ABI, biothesiometry, and plantar pressure measurement play an important role in planning management and need for diabetic footwear. The majority of the patients may have neuropathic involvement with a recurrence rate and need for amputation significantly reduced by the use of diabetic footwear.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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