Risk categorisation of patients attending a diabetic foot screening clinic in Suez

Diabetes is a growing public health problem in Egypt, with the prevalence of type 2 diabetes among adults in 2021 at 18.4 %.¹ Diabetic foot is defined by the International Working Group on the Diabetic Foot (IWGDF) as ‘infection, ulceration or destruction of tissues of the foot associated with neuropathy and/or peripheral artery disease in the lower extremity of a person with (a history of) diabetes mellitus'.²

The International Diabetes Federation (IDF) mainly attributes diabetic foot disease to neuropathy, peripheral arterial disease (PAD) and/or infection, often leading to ulceration and possible subsequent limb amputation. This can result in an economic, social and public health burden, especially in low-income communities, if there is neither an appropriate educational programme for patients about foot care and when to visit a physician, nor adequate and suitable protective or therapeutic footwear.³

The World Health Organization (WHO) has stated that diabetic foot is one of the costliest complications of diabetes, especially in communities with a lack of availability of appropriate footwear. It results from both vascular and neurological disease processes—changes in blood vessels and nerves—often leading to ulceration and subsequent limb amputation. Regular inspection and effective and timely foot care can prevent amputations.⁴ The use of comprehensive foot care programmes, including early screening and evaluation of problems, foot care education, preventive therapy and referral to specialists, has been shown to reduce amputation rates by 49–85%.⁵

Several authors have proposed classification systems in the past. Most of them incorporated neuropathy, bony foot deformity, history of ulceration or amputation, or various combinations of these. Of these classification systems, three also included peripheral vascular disease (PVD). Mayfield et al.⁶ validated their classification for amputations; Lavery et al.⁷ validated their classification for ulcerations; and Rith-Najarian et al.⁸ validated their classification for both ulcers and amputations.

The IWGDF classification differs from earlier classification systems because of the multidisciplinary and international group of clinicians and researchers involved in its conceptualisation. Some of the authors of other classification systems were also members of the IWGDF. The IWGDF foot risk classification predicts ulceration and amputation, and can function as a tool to prevent lower extremity complications of diabetes.⁹

It is important that people with diabetes, in particular those classed as IWGDF risk 1 or higher, should learn how to examine their feet daily, and identify any warning signs, such as:

• Changes in skin colour and/or skin temperature
• Swelling in the foot or ankle
• Leg pain
• Open sores on the feet that are slow to heal or are draining
• Ingrown toenails or toenails infected with fungus
• Corns or calluses
• Dry cracks in the skin, especially around the heel.

Patients also need to be aware of the preventive measures and actions needed when problems arise.¹⁰

Methods

Suez General Hospital Diabetes Foot Screening Clinic was held every Saturday by a family physician (the researcher) after approval of the Suez Governorate health authorities in November 2017.

For six months, all patients with type 2 diabetes attending the clinic were enrolled in the study after obtaining their verbal consent to participate. Ethical approval was not required for this study.

Full medical history, standard foot examination and data registration for each enrolled patient was done by the researcher. The history included:

• Name, age, job, marital status, address, family history of diabetes, diabetes duration, type of treatment, diet, exercise, smoking and associated comorbidities, i.e., cardiovascular, retinopathy, neuropathy or renal
• Past history of foot ulcers or amputations documented by date and site.

Patients' feet were evaluated and any findings were reported in a form specially designed for the study, including:

• Condition of skin, nails, presence of any deformity, and its type/location
• Vascular assessment by evaluating pulsations (aided by ultrasound Doppler)
• Neurological assessment (carried out using a 128Hz tuning fork and Semmes–Weinstein 10g monofilament) with loss of sensation at one or more sites on the plantar surface of the foot considered as presence of neuropathy.
• Foot care assessment was also documented whenever there was poor hygiene, long nails and inappropriate footwear.

Then, according to the IWGDF guidance,¹¹ patients were divided into four risk groups:

• Group 0: patients who had no distal sensory neuropathy
• Group 1: patients who had only distal sensory neuropathy
• Group 2: Patients with neuropathy who had foot deformity or/and vascular foot disease
• Group 3: Patients who had a history of prior foot ulcer or amputation.

Follow-up frequency was arranged with the patient according to their risk category:

• Once a year for patients in Group 0
• Every six months for patients in Group 1
• Every three months for patients in Group 2
• Monthly for patients in Group 3.

Any medications or referral were registered in the diabetic foot screening and risk assessment form noted above.

Statistical analysis

All data manipulation and statistical analyses were performed using the Statistical Package for Social Sciences (SPSS version 25.0; IBM Corporation, US). Categorical variables were presented as frequencies and percentages (%), while continuous variables were described as mean±standard deviation (SD) and range.

Associations between categorical variables were tested for statistical significance by Chi-squared test or Fisher's exact test (if >20% of expected values were <5). Differences between means were tested for statistical significance by the independent samples t-test. Multinomial logistic regression was performed where the ‘diabetic foot risk category’ was the dependent variable (risk Group 0 was set as the reference group), and the significant demographic and clinical risk factors served as the independent variables. Model fit was tested with likelihood-ratio test. A p-value of <0.05 was considered statistically significant.

Results

A total of 220 patients were enrolled in the study, of whom 65 (29.5%) were male and 155 (70.5%) were female. Patient age ranged from 19–85 years, with a mean of 54.6±10.3 years. Patients who were ≥60 years of age represented one-third (31.8%) of all participants. The majority of patients were married (80%), and 86.4% were living in urban areas. Of the participants, one-third (30.5%) were working, while 54% were homeworkers, with the remaining patients either retired or not working. With regards to lifestyle, 25 (11.4%) patients were smokers, 26 (11.8%) patients were regularly undertaking physical exercise, and 84 (38.2%) patients were controlling well their dietary intake (Table 1).

The duration of diabetes among study participants ranged from 1–40 years, with a mean duration of 11.7±7.6 years. More than half of patients (59.1%) had diabetes for ≥10 years, while 17.3% of patients had it for <5 years. About 45% of patients were taking oral hypoglycaemic medication, while about 55% were taking insulin. However, the majority of patients (78.6%) had uncontrolled diabetes. Only 8.6% had no diabetes-related complications. The most prevalent complications were neuropathy and cardiovascular disease (CVD), followed by retinopathy and nephropathy (82.3%, 62.3%, 22.7% and 6.4%, respectively) (Table 1).

In bivariate analysis (Table 2), the diabetic foot risk categories were significantly associated with a patient's age, sex, working status, disease duration, treatment regimen and diabetes-related complications. The percentage of patients with advanced risk categories (i.e., Groups 2 and 3) increased significantly with increasing age. Furthermore, male patients were more frequently classified to the advanced risk categories compared with female patients. Patients who were working and homeworkers tended to be more frequently classified to less advanced risk categories compared with retired and non-working patients.

Regarding disease-related factors, higher risk categories were significantly associated with a longer duration of diabetes, particularly ≥15 years. Patients taking insulin tended to be classified more frequently to the advanced risk categories compared with patients taking oral hypoglycaemic medication. Likewise, patients with diabetes-related complications (particularly neuropathy, CVD and retinopathy) tended to be classified more frequently to advanced risk categories compared with patients without complications. On the other hand, diabetic foot risk classification was not significantly associated with lifestyle factors such as smoking, physical exercise and dietary control.

Multivariate analysis (Table 3) showed that a patient's sex and diabetic complications had the most significant effect on risk classification. Compared with female patients, male patients were 6.94 times more likely to be classified as risk Group 3 rather than risk Group 0. Patients with diabetes who had systemic complications were 4.03 times more likely to be classified as risk Group 1 rather than risk Group 0, compared with patients with no complications.

The overall effect of patient age and the duration of their diabetes on their IWGDF risk classification was not statistically significant. However, patients aged ≥60 years were, significantly, 9.18 times more likely to be classified as risk Group 1 rather than risk Group 0, compared with patients <40 years (p=0.008). Likewise, patients with a long history of diabetes (≥15 years) were, significantly, 13.19 times more likely to be classified to risk Group 3 rather than risk Group 0, compared with patients with a shorter duration of diabetes (p=0.003).

Patients on insulin treatment were also, significantly, 2.63 times more likely to be classified as risk Group 1 rather than risk Group 0, compared with patients taking oral hypoglycaemic medication (p=0.002). This model as a whole fits significantly better than an empty model, with a likelihood-ratio Chi-squared of 81.51 and a p-value <0.0001.

Discussion

In this descriptive analytical study, patients were classified based on IWGDF criteria into four risk groups: 36.3% in Group 0; 37.7% in Group 1; 11.8% in Group 2; and 13.2% in Group 3. This is similar to a study by Cardoso et al. in Brazil adopting the same classification, where observed risks for stratification categories 0, 1, 2, and 3 were 28.2%, 29.4%, 23.5%, and 8.2%, respectively.¹² It was also similar to a study in by Kumar et al. in India, in which 32.9% of patients were in risk category 0, 42.4% in risk category 1, 15.2% in risk category 2, and 9.5% in risk category 3.¹³

However, the findings of this study are in contrast to those of studies which proposed that risk Group 0 was the most prevalent. A study by Tshitenge et al. in Botswana stated that 85% of patients were in risk category 0, 6.9% in risk category 1, 4.9% in risk category 2 and 3.5% in risk category 3.¹⁴ Another study by Shahbazian et al. found that 65% of patients were in risk category 0, 17% in risk category 1, 11% in risk category 2 and 7% in risk category 3.¹⁵ In a study by AlAyed et al. in Jordan, 82.8% of patients were in risk category 0, 6.2% in risk category 1, 8.2% in risk category 2 and 2.8% in risk category 3.¹⁶

This study showed that a patient's sex had the most significant effect on risk classification as male patients were more likely to be classified in the higher risk groups. This finding is consistent with the results of a survey in Alexandria, which found that 4.4% of patients with diabetes had a past history of non-traumatic amputation, past history of ulceration or active ulcer, with a majority of patients being male.^17,18,19,20 However, it is not consistent with Kumar et al.'s study which stated that being female was significantly associated with diabetic foot syndrome (DFS) (p=0.009).¹³

This present study also showed that diabetic complications (particularly neuropathy, CVD and retinopathy) had the most significant effect on risk classification (p=0.019; p=0.034; and p=0.005, respectively). This finding was supported by other studies which stated that patients in higher risk groups had more systemic complications of diabetes,^9,17 and that hypertension and ischaemic heart disease were significantly associated with DFS among study participants (p=0.000 and p=0.042, respectively).¹³

This study also found that IWGDF diabetic foot risk group was significantly associated with a patient's age, which is consistent with other studies,^{13,14,19,21,22} longer duration of diabetes,^{9,12,13,21,22,23,24} treatment with insulin^13,22 and working.

This study showed no significant correlation with smoking, which is not consistent with Kumar et al.'s study,¹³ control of diabetes—some studies stated that worse glycaemic control increased risk of diabetic foot ulcer,^9,21 or with exercise, control of diet, family history of diabetes, marital status or residence. This latter characteristic contrasts with the finding of the study by Salama et al.,²⁵ which stated that rural residence was identified as a risk factor for diabetic foot.

Limitations

Suez General Hospital had no database of patients with diabetes so cooperation with relevant authorities to prepare a complete database of such and their complications is a priority which will help future studies.

It was not usual practice in Suez to have a foot screening clinic for patients with diabetes and so patient attendance rates at the clinic were low. Further studies for the assessment of risk factors and incidence of ulcers in the followed patients using the more recent risk categorisation systems of IWGDF 2019 and IDF 2017 will be conducted.

Conclusions

This study showed that 62.7% of patients with diabetes were at high risk of developing ulcers and/or requiring amputation. Physicians should assess and apply foot risk categorisation for all patients with diabetes as early management or referral will prevent further complications. Further studies are also needed to identify the risk factors of diabetic foot ulcer and amputation in Egypt.

Reflective questions

• How can the prevalence of foot ulcer or amputation be reduced in high-risk patients with diabetes in Egypt?
• What are the risk factors for diabetic foot ulcer or amputation in patients with diabetes?
• How does the presence of systemic complications such as retinopathy, neuropathy and cardiovascular diseases in patients with type 2 diabetes impact on their risk of having a foot ulcer or amputation?