The findings of this study showed that approximately 80% of patients with a self-reported diagnosis of diabetes would have voluntarily examined their feet in the past eight years. Despite the relatively high proportion of patients with diabetes who initiate foot examinations, the proportion of patients without an active foot examination in the last 8 years is still quite high (17%). The study was conducted using NHANES data, a population-based survey, which represents the approximately 3.9 million people with diabetes with no active examination of their feet during the survey period. It is a worrying statistic showing the lack of awareness of foot ulcers among diabetics, leading to a multi-fold increase in the likelihood of foot ulcers being one of the most common clinical causes. Health care and community workers should provide targeted and individualized health education to patients with diabetes. Early identification and timely effective intervention of risk factors for DFU is essential for the management of DFU.
In this study, we introduced age, sex, race, poverty status, education level, BMI, smoking, glycohemoglobin, dyslipidemia, hypertension, walking limitations, diabetic retinopathy, renal failure, stroke and coronary heart disease as risk factors associated with patient-initiated foot examinations, and calculated the proportion of each factor in the different populations, as well as analyzing the correlation with active foot examinations in diabetic patients.
In the conventional theory of cognitive thought, there are differences in the perception of various items by age, gender, education level and even poverty status. Notably, the literature has indicated that the incidence of foot ulcers in diabetic patients increases with age, and is more common in males than females (3). However, this analysis revealed no statistical difference in these factors between diabetic patients who had their feet examined and those not examined. Studies had shown that the occurrence of diabetic foot ulcers increased with the amount of smoking (12). The nicotine in tobacco stimulates the release of epinephrine and norepinephrine, causing vasoconstriction and spasm, which results in tissue ischaemia and hypoxia and reduced tissue perfusion making diabetics prone to foot ulcers (13, 14). However, the findings in this study did not indicate a difference in smoking in diabetic patients between those who had their feet examined autonomously and the ones who did not. Basit et al. found that poor glycaemic control and high HbA1c stimulated endothelial cell apoptosis, accompanied by the production of large amounts of terminal glycosylation products, leading to luminal narrowing, which was strongly associated with diabetic foot ulcers (15, 16). Elevated blood lipids cause large amounts of lipid to invade the vessel wall, thickening the basement membrane and narrowing the lumen of the artery, causing an increase in endogenous clotting factors and predisposing the formation of blood clots, leading to diabetic foot ulcers (17). Although there is no clear relationship between walking limitations and the development of DFU, in type 2 diabetics, peripheral neuropathy is associated with fewer steps per day but no significant mobility impairment (18). Because of the disturbance of calcium and phosphorus metabolism in the body due to renal insufficiency, itching and dryness of the skin are often caused, and scratching is likely to break the skin and bruise it, once combined with infection will lead to diabetic foot. The diabetic foot and diabetic retinopathy are both microvascular complications of diabetes mellitus, and a correlation between the pathogenesis of the two has been demonstrated (19). However, these risk factors associated with the development of DFU in this study were not significantly different between diabetic patients who actively examined their feet and those who did not, suggesting that diabetic patients lack awareness of self-prevention of foot ulcers and have not yet realized the importance of effective assessment in the prevention of DFU.
A significant correlation was found between the prevalence of disease and ethnic variability, particularly in diabetes, so that the occurrence of diabetic foot may also differ between ethnic groups (3). The corresponding results in this study indicated that the importance of foot examinations varied by ethnicity, with the Non-Hispanic White population being the most important group for foot examinations, which may also account for the lower limb amputations in this group compared to Black/African Americans (20). Among the diabetic population, BMI above normal levels is associated with an increased chance of lower limb complications, which was also reflected in this study (21). However, there was no positive association between obesity and active foot examination after correction for covariates in the regression analysis. Elevated systolic blood pressure is an independent risk factor for the development of diabetic foot ulcers. A prospective study also found that systolic blood pressure was significantly higher in the diabetic foot ulcer group than in the non-diabetic foot ulcer group (22). Prolonged hypertension leads to weakened arterial wall elasticity, reduced compliance, increased intima-media thickness and endothelial cell damage, as well as reduced production of nitric oxide by endothelial cells or its bioavailability, thus accelerating the formation of atherosclerosis (23). The destruction of endothelial cells impairs vascular self-regulation and reduces blood supply to the foot, resulting in tissue ischaemia and hypoxia, leading to the development of diabetic foot ulcers. In addition, the regression analysis of this study also revealed a positive correlation in that diabetic patients with hypertension were more likely to initiate foot examinations.
This study exposed the population in which foot ulcers are mainly concentrated in diabetic patients on their own. The study analysis revealed that diabetic patients with high blood pressure were more proactive in checking for foot ulcers, possibly because blood pressure measurements were more easily done on a regular basis. The patients are actively checking their feet for ulcers whenever their blood pressure increases. Nevertheless, in summary, elevated blood pressure is only one possible cause of DFU, and the convenience of checking blood pressure leads patients to focus only on blood pressure and thus ignore other causes. Therefore, the specialist medical staff should provide patients and their families with more forms and richer contents of education related to foot protection and strengthen health education on prevention of diabetic foot. These health education measures enable patients to detect early prediabetic foot lesions, strengthen self-behavioral management and prevent the occurrence of ulcers.
Additionally, this study invokes population data in the NHANES database of 2011–2018, which suffers from a short time period and an inadequate population base, and the awareness of DFU prevention among the population has now changed over time. In subsequent studies, we will extend the time period and increase the population base, and combine the clinical patient follow-up data to provide a scientific reference for the prevention of DFU.