European Journal of Cardiovascular Medicine

Diabetes mellitus represents a major public health concern due to its increasing prevalence. According to estimates by the International Diabetes Foundation, India had approximately 65.1 million people living with diabetes in 2013, a number projected to rise sharply to 142.7 million by 2035 (1).

The human foot often serves as a reflection of systemic disease, and diabetes accounts for nearly 80% of all non-traumatic amputations (2). Mortality following such amputations remains alarmingly high, ranging between 39% and 80% within five years (3).

The World Health Organization (WHO) defines diabetic foot as *“the foot of a diabetic patient that has the potential risk of pathologic consequences, including infection, ulceration, and/or destruction of deep tissues associated with neurologic abnormalities, various degrees of peripheral vascular disease, and/or metabolic complications of diabetes in the lower limb (4). Unfortunately, diabetic foot continues to contribute significantly to the overall number of amputations.

Diabetic patients have a 15- to 40-fold higher lifetime risk of undergoing amputation compared with non-diabetic individuals. Those with ischemic or infected lesions face up to a 90-fold greater risk than those without such complications (5). Beyond the heightened risk of amputation and mortality, only about half of the diabetic patients who undergo amputation achieve satisfactory rehabilitation (6).

Nevertheless, many of these complications can be prevented through multidisciplinary teamwork and early intervention. Although factors leading to diabetic foot ulceration are well established, the specific risk factors associated with progression to amputation remain less clear and vary across studies.

Modern surgical approaches to diabetic foot have become increasingly conservative, aiming to minimize morbidity by avoiding unnecessary proximal amputations. Despite the fact that diabetes cannot yet be prevented entirely, proper glycemic control and patient education play crucial roles in delaying or reducing complications.

Bloom aptly noted that “the elderly diabetic is often divorced from his feet, unable to see them because of poor eyesight and unable to palpate them because of sensory loss.” The landmark discovery of insulin in 1922 by Nobel laureates Frederick Grant Banting and Charles Herbert Best revolutionized diabetes management, reducing the mortality rate from surgical complications from 60% in the pre-insulin era to just 1% (7).

The present study aims to identify and quantify independent risk factors for lower-extremity amputation in our patient population. Understanding these variables will help recognize modifiable risk factors and guide the development of targeted preventive and therapeutic strategies to reduce amputation rates at the institutional level.

Study Design and Setting: This descriptive analytic study was conducted on patients aged between 18 and 80 years who presented with diabetic foot and its related complications. The study was carried out at Sri Ramakrishna Hospital, Coimbatore, Tamil Nadu, including patients from Coimbatore city and nearby villages who provided informed consent to participate. The study period spanned two years, from November 2014 to November 2016. A total of 150 diabetic foot patients (both inpatients and outpatients) were included in the study based on predefined inclusion and exclusion criteria.

Inclusion Criteria

1. Patients above 18 years of age presenting with diabetic foot disease and willing to participate in the study.
2. Patients with a history of amputation presenting with a diabetic ulcer on the same or opposite foot.

Exclusion Criteria

1. Patients with carcinoma, vasculitis, connective tissue disease, or immune system disorders, and those on corticosteroids, immunosuppressants, radiotherapy, or chemotherapy.
2. Patients with amputations due to causes other than diabetes, such as trauma or frostbite.
3. Patients with peripheral vascular disease alone, without diabetes mellitus.
4. Patients unwilling to participate or unable to provide consent.
5. Patients younger than 18 years.
6. Patients with psychiatric illness who are unable to care for themselves.

Data Collection Method: Each patient was subjected to a detailed evaluation, including history taking, physical examination, and relevant laboratory and imaging investigations.

History and Clinical Evaluation: Information was collected regarding age, sex, duration of diabetes, family history, personal habits (smoking, alcohol use, tobacco chewing), and any prior amputations. Physical examination included assessment of both feet for:

• Ulcer presence, site, size, and duration
• Depth of ulcer and surrounding skin changes
• Edema, cellulitis, discharge, and local temperature
• Presence of neuropathy (sensory, motor, or autonomic)

Sensory Neuropathy: Assessed using a 10 g monofilament applied to 10 standard sites on the foot. Inability to perceive the filament indicates large-fiber neuropathy.

Ischemia Assessment: Doppler ultrasonography was used to evaluate blood flow. Non-palpable dorsalis pedis or posterior tibial pulses indicated ischemia.

Foot Deformity Assessment: Any contracture not fully correctable manually, such as hallux valgus, hammer toes, claw toes, hallux rigidus, or ankle equinus, was considered a deformity.

Charcot Arthropathy: Defined as fractures or dislocations of foot and ankle bones occurring with minimal trauma due to neuropathy or sensory loss.

Laboratory evaluation included:

• Complete blood count
• Fasting blood glucose and HbA1C levels
• Blood urea and serum creatinine
• Urine examination for albuminuria

Radiological evaluation included foot X-rays, Doppler ultrasonography, and chest X-rays when necessary.

Microbiological Evaluation: Deep tissue or pus samples were sent for culture and sensitivity testing in cases of infection. Empirical antibiotic therapy was started covering Gram-positive, Gram-negative, and anaerobic organisms and later modified according to culture results.

Treatment Protocol

• Regular dressing and debridement were performed as required.
• Drainage of abscesses or collections was carried out when indicated.
• Amputation was considered in cases of gangrene, severe infection, or non-response to medical therapy.
• Post-amputation care included antibiotics and supportive therapy until complete healing.

Statistical Analysis: Data from all 150 patients were analyzed using SPSS version 17.0. Descriptive statistics such as mean and standard deviation were calculated. Comparative analyses were performed using Student’s t-test or ANOVA, with a p-value < 0.05 considered statistically significant. Significant variables were identified as independent risk factors for lower limb amputation.

Table 1: Age and Gender Distribution of Diabetic Foot Patients

Table 1 presents the distribution of diabetic foot patients according to age and gender. Out of the total 150 patients studied, 98 (65.3%) were males and 52 (34.7%) were females, indicating a clear male predominance. The majority of cases occurred in the 51–60 years age group (40%), followed by the 61–70 years group (28.7%), reflecting that diabetic foot complications are more common in the middle-aged and elderly population. In all age categories, males outnumbered females, suggesting that men are more frequently affected, possibly due to higher occupational exposure, lifestyle factors, and lesser health-seeking behaviour compared to women.

Figure 1: Distribution of Non-Amputated, Minor, and Major Amputation Cases among Diabetic Foot Patients

Figure 1 illustrates the overall distribution of amputation status among 150 diabetic foot patients. More than half of the patients (50.7%) were successfully managed without any amputation. However, 49.3% of cases required surgical removal of affected parts, out of which 33.3% underwent minor amputations (such as toe or ray amputations) and 16% underwent major amputations (below- or above-knee).

Table 2: Association of Duration of Diabetes, Smoking, and Peripheral Vascular Disease (PVD) with Amputation Status among Diabetic Foot Patients

Table 2 shows the relationship between the duration of diabetes, smoking habits, and presence of peripheral vascular disease (PVD) with the occurrence and severity of amputations among diabetic foot patients.

Patients with longer duration of diabetes (>11 years) showed a higher proportion of major amputations (21.1%) compared to those with shorter duration, indicating chronicity as a strong risk factor for severe limb involvement. Similarly, smokers had markedly higher rates of both minor (48.0%) and major amputations (24.0%) than non-smokers, highlighting smoking as a major modifiable risk factor contributing to vascular compromise and poor wound healing.

Regarding PVD, patients with vascular insufficiency exhibited greater rates of minor amputations (39.7%), while those without PVD had a higher incidence of major amputations (23.0%), possibly reflecting differing pathophysiological mechanisms in tissue loss progression. Overall, these findings underscore that longer diabetes duration, smoking, and PVD significantly increase the risk and severity of amputations in diabetic foot disease.

Table 3: Association of HbA1C Levels, Neuropathy, Ulcer Presence, and PEDIS Grade with Amputation Status among Diabetic Foot Patients

Table 3 demonstrates patients with poor glycemic control (HbA1C in the diabetic range) showed a markedly higher rate of both minor (33.6%) and major (16.1%) amputations, whereas no amputations occurred in the pre-diabetic category, highlighting the direct impact of uncontrolled diabetes on limb outcomes.

Neuropathy was strongly associated with amputation severity 26.7% of patients with neuropathy required major amputations compared to only 8.9% among those without neuropathy, indicating that sensory loss predisposes to unnoticed injuries and ulceration.

The association between neuropathy and ulceration further reinforces this, as 40% of neuropathic patients had active ulcers, compared to only 13.3% among non-neuropathic individuals.

Regarding PEDIS grading, higher grades were closely related to the severity of tissue damage. All Grade 2 cases were managed conservatively, while Grade 3 and Grade 4 cases accounted for most minor and major amputations, respectively. This pattern shows that increasing PEDIS grade corresponds to worsening infection and ischemia, making amputation more likely.

Figure 2: Distribution of Microorganisms Isolated from Diabetic Foot Infections

The figure 2 illustrates the distribution of microorganisms isolated from diabetic foot infections in the study population. The most frequently isolated organism was Pseudomonas species (15.3%), followed by Staphylococcus aureus (12.7%), ESBL-producing organisms (10.7%), and MRSA (9.3%). Klebsiella (8.7%), Proteus (5.3%), and MSSA (5.3%) were also identified in smaller proportions, while mixed infections involving Klebsiella and MSSA accounted for 1.3% of cases. Notably, no bacterial growth was observed in 31.3% of samples, likely due to prior antibiotic use or inadequate tissue sampling. Overall, the results highlight that Pseudomonas and Staphylococcus aureus are the predominant pathogens in diabetic foot infections, underlining the importance of targeted antibiotic therapy guided by culture and sensitivity testing.

Table 4: Distribution of Local Complications among Diabetic Foot Patients

*Corrected total percentage for ulcer category to maintain consistency (82.0% instead of 92.0%).

Table 4 presents the prevalence of various local complications associated with diabetic foot among 150 patients. The most frequent finding was ulceration (18%), followed closely by gangrene (16.7%), abscess formation (16%), and cellulitis (16%) indicating that infection and tissue necrosis are common outcomes of poorly controlled diabetes and peripheral vascular compromise. Other complications such as osteomyelitis (12.7%), rest pain (10%), necrotizing fasciitis (5.3%), and Charcot’s foot (5.3%) were less frequent but clinically significant, as they often indicate advanced disease requiring aggressive management.

Table 5: Association between Previous History of Amputation and Current Amputation Status among Diabetic Foot Patients

Chi-square = 2.882, df = 2, p = 0.237 (Statistically not significant)

Table 5 examines the relationship between a previous history of amputation and the current amputation status among diabetic foot patients. Of the total 150 patients, 32 (21.3%) had undergone amputation previously. Among them, 34.4% required another minor amputation and 25% required a major amputation during the study period.

Although a slightly higher proportion of patients with previous amputations required further surgical interventions compared to those without prior amputations, the association was not statistically significant (p = 0.237).

Table 6: Distribution of Ischemic and Neuropathic Involvement among Diabetic Foot Patients

Table 6 demonstrates the prevalence of ischemic and neuropathic components among 150 diabetic foot patients. Ischemia was present in 35.3% of cases, indicating significant peripheral arterial compromise contributing to poor wound healing and increased amputation risk. Neuropathy was observed in 40% of patients, reflecting the role of sensory loss and impaired protective response in ulcer formation and progression.

Table 7: Association of Foot Deformity with Duration of Diabetes, Ulceration, and Amputation Status among Diabetic Foot Patients

Table 7 summarizes the relationship of foot deformity with duration of diabetes, presence of ulceration, and amputation status among 150 diabetic foot patients.

Patients with a shorter duration of diabetes (<10 years) accounted for the majority of deformities (85.7%), suggesting that structural changes can develop early, possibly due to undiagnosed neuropathy or poor glycemic control. Foot deformity was more common in patients with ulcers (28.6%) compared to those without (21.3%), indicating that deformity increases plantar pressure and predisposes to ulceration.

Regarding amputation, 25% of patients with deformity required major amputations, compared to only 10.6% among those without deformity. This shows a clear association between deformity and the severity of limb loss, as structural abnormalities can impair healing and increase the risk of recurrent infections.

Table 8: Association of Peripheral Vascular Disease (PVD), Systemic Hypertension, Renal Failure, and Coronary Artery Disease (CAD) with Amputation Status among Diabetic Foot Patients

Table 8 assesses the association between major comorbid conditions and the occurrence of amputations in diabetic foot patients. Peripheral vascular disease (PVD) showed a significant relationship (p = 0.020), with higher rates of both major and minor amputations among affected individuals, confirming vascular insufficiency as a strong determinant of limb loss. Systemic hypertension (p = 0.001) and renal failure (p = 0.001) were also found to be statistically significant, indicating their contributory role in poor microvascular perfusion and impaired wound healing. Conversely, coronary artery disease (p = 0.343) did not show a significant association with amputation in this study population.

This prospective study was carried out on 150 patients with diabetic foot disease treated at the Department of General Surgery, Sri Ramakrishna Hospital, Coimbatore, from November 2014 to November 2016. The data were analyzed using the SAS (Study, Analyse and Subgroup) protocol, ensuring systematic and in-depth evaluation of multiple clinical parameters and subgroups.

Out of the 150 cases, 98 (65.3%) were males and 52 (34.7%) were females, demonstrating a clear male predominance (ratio 1.8:1). The higher male incidence may be attributed to greater outdoor activity, occupational exposure, barefoot walking, smoking, and alcohol consumption. Most patients belonged to the 51–60 years age group, which is consistent with A.K. Ramani et al. (51–60 years) but younger than Western studies such as Badderly and Fulfold (61–70 years) and Oakley et al. (71–80 years). This suggests that diabetic complications tend to occur at an earlier age in the Indian population (9-11).

In terms of clinical presentation, ulceration (18%), abscess (16%), cellulitis (16%), and gangrene (16.7%) were the predominant features, followed by osteomyelitis (12.7%), rest pain (10%), Charcot’s foot (5.3%), and necrotizing fasciitis (5.3%). The incidence of neuropathy was 40% and ischemia 35.3%, indicating that diabetic neuropathy and vasculopathy are the primary mechanisms underlying ulceration and tissue loss.

The overall amputation rate was 49.3%, of which 16% were major amputations (below or above knee) and 33.3% were minor amputations (Ray, Lisfranc, or Chopart). Half of the patients (50.7%) were successfully managed conservatively with antibiotics, debridement, and local wound care. Compared with earlier studies Pittet et al. (12) the amputation rate in this series was higher, likely reflecting delayed presentation and advanced disease at the time of admission.

Foot infection was seen in 68.6% of patients. The most common isolates were Pseudomonas (15.3%) and Staphylococcus aureus (12.7%), consistent with reports from Jones et al. and Lipsky et al., though the proportion of Staphylococcus was lower in this study (13). Most cultures were monomicrobial, emphasizing the diagnostic value of deep tissue samples over superficial swabs.

Peripheral vascular disease was detected in 42% of patients, comparable with D.K. Rastogi (44.3%) and Ramani et al. (49.35%), confirming its strong association with ischemic changes in diabetic feet. Neuropathy was present in 40% of cases lower than the 59.4% and 67% reported by Sumpio et al. and Murray et al., respectively but still a major contributor to ulceration and deformity (14).

Univariate analysis identified smoking, peripheral vascular disease, neuropathy, higher PEDIS grade (≥3), and the presence of comorbidities as statistically significant risk factors for amputation. In contrast, duration of diabetes, HbA1C level, previous amputation, and foot deformity were not independently significant. These findings indicate that microvascular and neuropathic complications, compounded by infection and systemic comorbidities, play a more decisive role in predicting limb loss than disease duration or glycemic status alone.

The major amputation rate (16%) in this study was comparable and lower than Leung et al. (30.3%), suggesting that timely surgical intervention and conservative management helped reduce extensive limb loss (15). However, the higher overall amputation rate reflects the persistent challenge of late presentation and limited awareness regarding foot care among diabetic patients.

The study duration was limited to two years, restricting long-term follow-up. Although the sample size was adequate for statistical analysis, a larger multicentric cohort could provide more robust and generalizable results

This study reaffirms that diabetic foot disease is a multifactorial complication arising from neuropathy, ischemia, and infection. Most patients presented with advanced disease requiring surgical intervention. Early recognition of risk factors particularly neuropathy, peripheral vascular disease, and infection along with strict glycemic control, smoking cessation, appropriate footwear, and regular foot examinations are critical in reducing the burden of amputation.

A multidisciplinary approach involving diabetologists, vascular surgeons, orthopedic specialists, and wound care teams is essential for effective management and prevention of limb loss. With focused patient education and preventive strategies, the rate of diabetic foot complications and amputations can be substantially minimized, improving both quality of life and long-term survival.

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