Introduction

Diabetes is a metabolic disorder characterized by high blood sugar levels and is one of the most common chronic non-communicable diseases worldwide [1]. According to the International Diabetes Federation (IDF) guidelines, there were approximately 537 million people with diabetes worldwide in 2021, and this number is expected to rise to 643 million by 2030 [2]. In China, the prevalence of diabetes in the mainland area is 11.2%, making it the country with the highest number of diabetes patients in the world [3, 4]. Long-term high blood sugar can lead to various diabetes-related complications, particularly in the eyes, kidneys, heart, blood vessels, and nerves, with diabetic foot ulcer (DFU) being the most common and serious [5]. The prevalence of DFU worldwide varies from 1.6% to 8.0% [6], and is estimated to reach 19% by 2045 [7]. DFU is associated with high incidence and mortality rates worldwide, with amputation rates as high as 74% for new DFU patients and 5-year mortality rates of 43% ~ 55% [8]. The annual cost of care is approximately 81.7 billion US dollars [9]. The rapid increase in global incidence rates and high treatment costs impose a heavy economic burden on patients, families, and society.

A comprehensive approach to foot care, including prevention, education for patients, multidisciplinary collaboration in managing foot ulcers, and close monitoring, leading to a reduction in amputation rates by 49% ~ 85% [10]. Perrin et al. [11] conducted a cross-sectional survey of 121 patients and divided them into three groups according to their knowledge of DFU development: one group had misconceptions about peripheral neuropathy, another group had a relatively accurate understanding of that, and the third group had no knowledge of foot conditions. The results showed that the group with misconceptions had more potentially destructive foot care behavior than the other groups, indicating that correct knowledge of foot care can guide appropriate foot care behavior and have impacts on foot conditions directly. In addition, physical factors such as wearing inappropriate footwear and socks, improper toenail trimming, and burns account for more than 75% of the factors leading to DFU, and good care can prevent the injuries from occurring [12]. Early identification of high-risk factors for diabetic foot and providing targeted interventions and management is crucial for preventing DFU.

The International Working Group on the Diabetic Foot (IWGDF) 2015 guidelines recommend implementing health education, prevention measures, and follow-up duration according to different foot risk levels [13]. However, previous studies have focused mainly on the overall population of diabetes patients, with little differentiation of DFU risk status among people with diabetes, making it difficult to provide targeted prevention measures based on research findings [14, 15]. Though a recent study failed to find significant difference in foot care knowledge and behavior scores among diabetes patients with different DFU risks [16], the authors suggested further studies be necessary on exploring the foot care knowledge and behavior of people with diabetes with different foot risk levels.

Therefore, this study has three objectives: (1) to assess the foot risk level of people with diabetes; (2) to describe the current status of foot care knowledge and behavior among people with diabetes with different foot risks; (3) to explore the impact of foot knowledge and behavior on high-risk foot occurrence in people with diabetes and other key factors.

Materials and methods

Study design

This is a cross-sectional study using convenience sampling, and including people with diabetes who were hospitalized in the endocrinology department of two tertiary hospitals in northern China between June 2021 and December 2022. All patients who met the inclusion criteria were enrolled in the study.

Inclusion criteria: people with diabetes diagnosed by a regular medical institution according to the 1999 diagnostic criteria of the World Health Organization, aged ≥ 18 years, with normal cognitive function and good communication skills, and willing to participate in the study.

Exclusion criteria: patients who had undergone major amputations (above the ankle), those with severe impairment of heart, liver or kidney function, those with severe diabetic complications, and nondiabetic neuropathy such as central nervous system injury, prolapse of lumbar intervertebral disc, and congenital neuropathy.

Sample size calculation

We used the formula for calculating the sample size of a single rate 95% confidence interval for cross-sectional studies: sample size \(N={\left(\frac{{Z}_{1-\alpha }}{\delta }\right)}^{2}P\left(1-P\right)\).

A previous study [17] indicated that the DFU 60-s screening tool can identify 37% to 48% of diabetic high-risk foot patients. In this study, we selected a p value of 37% and allowed for an error range of ± 5%. The calculated sample size was 359 patients, and a 10% expansion was added, resulting in a final sample size of 395 patients. A total of 410 patients were ultimately enrolled in this study, meeting the sample size requirements.

Data collection tool

The questionnaire used in this study consists of three parts: (1) demographic and disease-related information developed by the investigators. The demographic information includes age, gender, education level, marital status, occupation, smoking, and alcohol intake. The disease-related information includes duration of illness, fasting blood-glucose, other chronic diseases (hypertension, coronary heart disease, COPD, and cerebrovascular disease), history of diabetic foot ulcer and amputation. (2) Foot stratification methods, which were applied according to the IWGDF guidelines and the Guidelines for the Prevention and Treatment of Type [18]. The screening for high-risk diabetic foot includes assessment of peripheral neuropathy, peripheral vascular disease, and foot deformities using various tests such as pressure sensation (10 g monofilament test), vibration perception (128 Hz tuning fork test), ankle reflex, pinprick sensation, temperature sensation, ankle-brachial index (ABI), intermittent claudication, and rest pain. Foot deformities include hallux valgus, toe deformities (such as claw toe, hammer toe, and mallet toe), metatarsal head protrusion, and post-amputation deformities. Risk stratification is based on the screening results, with Grade 0 indicating low-risk foot and Grades 1–3 indicating high-risk diabetic foot (Table 2). (3) Investigation of knowledge and behavior related to foot care using the knowledge and behavior Foot Care Scale [18], which consists of 17 items related to five aspects of foot care: examination of footwear and socks, foot cleansing and maintenance, selection of shoes and socks, risky behaviors related to foot injuries, and management of foot problems. The total score is converted into a standard score with a range of 0–100, with lower scores indicating poorer knowledge and behavior related to foot care. The reliability of the questionnaire was assessed using Cronbach's α coefficient, which was 0.824 for the knowledge questionnaire and 0.768 for the behavior questionnaire.

Data analysis

The collected data were checked for completeness and coded. Then, the data were entered into EpiData version 3.1 and then exported to SPSS version 24.0 for analysis. Normally distributed continuous variables were presented as mean ± standard deviation, and non-normally distributed continuous variables were presented as median and quartile range. Categorical variables were presented as frequency and percentage. Multiple logistic regression analysis was performed with high-risk foot as the dependent variable and statistically significant variables in the univariate analysis as independent variables. Differences were considered statistically significant if p < 0.05.

Ethical consideration

This study has been approved by the hospital's ethics committee, and all participants have provided informed consent and voluntarily participated in the study.

Results

Sociodemographic and disease-related characteristics

Sociodemographic characteristics

The study population was predominantly composed of individuals aged 61 years or older (37.1%), with a roughly equal distribution of men and women (52% and 48%, respectively). Approximately half of the patients had a middle to high school education (48.6%), and most were married (82.2%). The majority of the patients were retired (76.6%) (Table 1).

Table1 Sociodemographic and Disease-Related Characteristics of the study population (n = 410)
Full size table

Disease-related characteristics

The majority of the patients had never smoked (63.4%), and had never alcohol intake (65.6%). The duration of diabetes was mostly greater than 10 years (60.7%), and the fasting blood-glucose was poor control (87.6%). The most common comorbidities were hypertension (55.4%) and coronary heart disease (29.3%) (Table 1).

Diabetic foot risk stratification

Among the 410 patients, a total of 367 (89.5%) were identified as high-risk for diabetic foot, while 43 (10.5%) were low-risk diabetic foot. Specifically, there were 135 (32.9%) patients for grade 1 high risk feet, 202 (49.3%) for grade 2 high risk feet, and 30 (7.3%) for grade 3 high risk feet (Table 2). The results of the three IWGDF screening tests are provided in Table 7 Appendix 1.

Table 2 DFU risk stratification (n = 410)
Full size table

Foot care knowledge and behavior status

Foot care knowledge score

The foot care knowledge questionnaire score was 50.65 ± 18.60 (ranging from 5.88 to 94.12). The scores of each dimension in descending order were: foot injury risk behavior, foot cleanliness and maintenance, shoes and socks selection, foot and shoes inspection, and foot problem management (Table 3). The specific scores for each item are shown in Table 8 Appendix 2.

Table 3 Scores of foot care knowledge questionnaire dimensions for patients (n = 410)
Full size table

Foot care behavior score

The score of the foot care behavior questionnaire for 410 people with diabetes was 54.46 ± 11.87 (ranging from 19.61 to 86.27). The scores of each dimension, from high to low, were foot cleaning and maintenance, selection of shoes and socks, examination of feet and footwear, management of foot problems, and risky foot behavior (Table 4). The scores for each item in the foot care behavior questionnaire are shown in Table 9 Appendix 2.

Table 4 Scores of foot care behavior questionnaire dimensions for patients (n = 410)
Full size table

Knowledge and behavior status of people with diabetes at different foot risk

Univariate analysis of variance found no statistically significant differences in knowledge scores among people with diabetes at different foot risk levels. However, there was a statistically significant difference in behavior scores (p < 0.05) among the different foot risk levels (Table 5).

Table 5 Knowledge and behavior status of diabetic patients with different foot risk classifications (n = 410)
Full size table

Analysis of risk factors associated with diabetic high-risk foot

Univariate analysis showed that there were statistically significant differences in age, occupation, the history of cerebrovascular disease, foot care knowledge standard score, and foot care behavior standard score between patients with high-risk and low-risk diabetic foot (p < 0.05), as shown in (Table 6). Using the presence of high-risk diabetic feet as the dependent variable, and the factors that showed statistical significance in the univariate analysis as independent variables, a multiple logistic regression analysis was conducted. Age, the standard scores for foot care knowledge and behavior were used as original values, and the remaining variables were set as dummy variables, with good fasting blood glucose control, retired, and no history of cerebrovascular disease as reference levels. The multiple logistic regression analysis showed that age, the history of cerebrovascular disease, and the foot care behavior score were the influencing factors for people with diabetes to develop high-risk feet (Table 6).

Table 6 Univariate and Multivariable logistic regression analysis for high-risk foot in patients with diabetes (n = 410)
Full size table

Discussion

Late complications of diabetes, especially DFU, can lead to amputation, functional decline, increased financial burden for patients, and a sharp decline in their quality of life. Therefore, preventing DFU is necessary. To our knowledge, this is the first such survey conducted in northern China to determine the status of foot care knowledge and behaviors of patients with different DFU risk levels during hospitalization in a tertiary hospital, as well as the related risk factors for high-risk foot development.

In this study, a total of 367 cases of high-risk foot (89.5%) and 43 cases of low-risk foot (10.5%) were screened. Among them, 135 cases (32.9%) were classified as grade 1 high-risk foot, 202 cases (49.3%) were grade 2 high-risk foot, and 30 cases (7.3%) were grade 3 high-risk foot. Compared with previous studies, the overall detection rate of high-risk foot in this study was relatively high [19, 20]. This may be due to the fact that tertiary hospitals in China usually admit difficult and critically ill patients, who are older, have a longer course of disease, and more complications [21]. Screening for high-risk foot as the first step in DFU prevention should be given more attention by healthcare workers. However, in practice, medical staff often pay more attention to patients' blood glucose control and the management of related complications, and insufficient attention is paid to the early screening of high-risk foot. Therefore, in patient education, the importance of high-risk foot screening should be emphasized first. Additionally, it may be related to the increase in screening tools. Previous studies mainly focused on single examinations for high-risk foot screening [22, 23], while the research tool used in this study had more screening items and higher sensitivity, resulting in more cases of neuropathy being detected [18]. Currently, research on high-risk foot screening tools is still in its early stages. Developing a systematic and simple method for high-risk foot screening and making it easy to implement in various settings can better serve people with diabetes for high-risk foot screening.

The results of this study indicate that the knowledge and behavior scores for foot care in people with diabetes were at a moderately low level. In terms of foot care knowledge, patients had good knowledge of foot cleaning and maintenance, as well as knowledge of the risk behaviors associated with foot injury. However, their knowledge of shoes and socks selection, examination of feet and footwear, and management of foot problem was insufficient, particularly in terms of knowledge of the need for regular foot checkups at the hospital and applying moisturizing cream after washing their feet. This is similar to the findings of Zheng et al. [24], which showed that patients had limited knowledge of foot care and shoes selection. Due to cultural differences, many Chinese people habitually soak or wash their feet in warm water daily, which may not indicate sufficient knowledge of foot cleaning and maintenance [16]. Therefore, when providing patient education, it is important not only to explain the correct knowledge, but also to inform patients about the harmful effects of incorrect knowledge on the development of DFU, so that patients can consciously accept correct knowledge of DFU and maintain good foot behaviors.

In terms of foot care behavior, patients had good behaviors in foot cleaning and maintenance and shoes and socks selection, but poor behaviors in feet and footwear examination, foot injury behavior, and foot problem management, particularly in terms of patients not being able to visit the hospital for regular foot checkups, not being able to trim their toenails correctly, and wearing slippers in bare feet. This is consistent with the findings of Long et al. [25], which showed that regular foot checkups were the worst behavior of people with diabetes. However, the findings of Maha Obaid Alharbi [26], which indicated that over 50% of patients demonstrated good foot care behaviors, appear to differ from the results of our study. One possible explanation for this discrepancy is the absence of specialized foot clinics in community or general hospitals in China, as well as the lack of regular foot checkups included in diabetes follow-up. As a result, patients mainly rely on their own knowledge and daily habits for foot care, and may not fully appreciate the importance of good foot care behaviors in preventing foot complications. Therefore, it is necessary to provide prevention methods and educational programs for foot ulcers, encourage patients to regularly check their foot condition, and promote the establishment of self-care behaviors.

The results of this study showed no statistically significant difference in foot care knowledge scores among patients with different levels of foot risk, while statistically significant differences were found in foot care behaviors. This may be related to the insufficient emphasis on DFU prevention in various medical institutions in China, and even if patients develop DFU, medical staff tend to focus more on regulating blood glucose, controlling infection, improving nutrition, and neglecting the impact of preaching foot care knowledge on DFU. In addition, this study found a statistically significant correlation between foot condition and patient age and foot care behavior, indicating that as patients age and their personal knowledge reserves increase, they will pay more attention to blood glucose monitoring and control, and establish good behavioral habits [27]. However, the source of this difference is not that medical staff have health education targeted at patients with different foot risk levels, but rather the natural differences in lifestyle habits that arise as patients' educational levels increase and their disease awareness deepens with age. Therefore, it cannot be assumed that as patients' foot risk levels increase, their foot behavior will improve.

The results of this study showed that age is an important predictive factor for high-risk diabetic foot patients. Other studies have also indicated that people with diabetes over 60 years of age are three times more likely to experience peripheral neuropathy than those under 60 [28, 29]. This may be due to age-related visual impairment, which may limit the ability to conduct normal foot and footwear examinations, as well as the presence of osteoporosis and poor coordination. Therefore, education on foot care should be provided to elderly patients and their families. The results of this study also showed that having cerebrovascular disease is an important risk factor for high-risk feet. This is consistent with the results of a cross-sectional survey that included 62,681 patients [30]. That study showed that cerebrovascular disease, age ≥ 45 years, and poor glycemic control were all important risk factors for DFU. This may be due to the fact that people with cerebrovascular disease often have limb sensory impairments, which can lead to delayed diagnosis and treatment. It is recommended that patients with cerebrovascular disease undergo regular foot examinations to assess their risk status and ensure early detection and treatment of foot problems.

In addition, the results of this study show that foot care behaviour scores are also a risk factor for diabetic high risk feet. This finding highlights the importance of patient self-management in preventing complications of DFU. This is consistent with previous research, indicating that foot care practices are crucial for preventing and managing complications of DFU [27]. Relevant studies have shown that the development of foot care education programs can improve foot health outcomes and reduce the incidence of diabetes complications [31]. Therefore, healthcare providers should emphasize the importance of foot care behavior in diabetes management and incorporate this education into their treatment plans to further improve the quality of life of patients .

Limitations

The sample collection for this study was conducted only at two tertiary hospitals in northern China, which may limit the representativeness and generalizability of the findings. In addition, as this study was designed as a cross-sectional study, causal relationships cannot be inferred. Furthermore, due to the short study period, we were unable to diagnose the late outcomes of people with diabetes and observe the progression of their high-risk feet.

Conclusions

The prevalence of high-risk feet in patients with diabetes was found to be high in tertiary hospitals in northern China, with more cases of grade 1 and grade 2 high-risk feet, and poor knowledge of diabetic foot prevention and foot care behavior. We found that age, history of cerebrovascular disease, and foot care behavior score significantly influenced the incidence of high-risk feet in patients. Therefore, it is necessary to strengthen follow-up and education on diabetic foot prevention knowledge for patients who are elderly, suffer from cerebrovascular diseases, and have lower foot care behavior scores. The results of this study can guide the future resource promotion for the most needed groups, thereby helping to reduce the incidence of diabetic feet in adult populations.