Diabetic foot is one of the most common, costly, and severe complications of diabetes, with an estimated limb or part of a limb lost every thirty seconds. Consequently, diabetic foot (DF) represents a significant public, economic, and social health challenge (13). However, not all individuals with diabetes are at risk for ulceration. The primary risk factors include loss of protective sensation (LOPS), peripheral arterial disease (PAD), and foot deformities (7). LOPS diminishes the foot’s response to harmful external stimuli, often leading to ulcers due to unperceived repetitive pressure in specific areas; PAD is considered an independent risk factor that impacts wound healing and the necessity for amputation (14–16). Most research focuses on the incidence of LOPS and PAD, with less attention given to foot deformities. Diabetic peripheral neuropathy (DPN), PAD, and foot deformities are relatively common among diabetic patients, inflicting physical and emotional distress on patients and their families, thereby affecting their quality of life (17). Understanding the prevalence and risk factors of DPN, PAD, and foot deformities is crucial for developing preventive strategies for diabetic foot in diabetic patients. Therefore, we conducted a multi-community diabetic foot screening across nine communities in Xiamen, ultimately analyzing 1,224 cases from the natural diabetic population to determine the prevalence and risk factors of diabetic foot disease among individuals over 60 years old.

This study found that the incidence of at-risk diabetic foot in the diabetic population over 60 years old was 33.50%, which differs from the 27.8% reported by Ren et al. (2), possibly due to differences in the study populations and regions. Chen et al. (18), who included 13,315 diabetic patients in their study, reported that 4.9% of the patients had PAD and 43.9% had DPN. This contrasts significantly with our findings, where 16.42% of participants had PAD and 22.54% had LOPS. The discrepancy may be due to Chen et al. using only a 10 g monofilament for diagnosing DPN and an ankle-brachial index (ABI) less than 0.9 for diagnosing PAD, without considering decreased vibratory perception and ABI greater than 1.3, and only reporting the incidence of diabetic peripheral neuropathy and PAD without attention to foot deformities. Liu et al. (17) conducted an epidemiological survey of diabetic patients in outpatient clinics across 11 hospitals in Beijing, focusing on foot deformities and reported a deformity incidence of 29.7%, similar to our finding of 22.79%. Our study, based on the IWGDF 2023 stratification, not only reports the incidence of LOPS, PAD, and foot deformities but also addresses the incidence of conditions combining LOPS with PAD, LOPS with foot deformities, and PAD with foot deformities. We also found that even in the very low-risk group, the incidence of foot deformities was as high as 23.90%, a clinically significant issue since even non-diabetic patients with foot deformities can develop skin ulcers at the deformity site. Therefore, whether interventions for foot deformities in the very low-risk group are warranted merits further study. The IWGDF guidelines focus more on the contribution of LOPS and PAD to the risk of diabetic foot and also consider foot deformities but do not describe toenail deformities. Our study addresses toenail deformities and inappropriate footwear, as we have observed in clinical practice that some cases requiring toe amputation in diabetic foot are due to toenail deformities and improper toenail trimming. Therefore, this aspect was included in our screening process and presented in the results. Additionally, we focused on the mobility of the foot and ankle joints, as joint mobility is crucial in the gait cycle, and limited mobility can lead to abnormal pressure in certain areas of the footed (19–21), similar to foot deformities, becoming a risk factor for diabetic foot. Due to the challenges of community screening, the typical study populations in Chinese research are hospitalized or outpatient diabetic patients, which do not represent the prevalence and characteristics of the natural diabetic population. Based on the latest guidelines and comprehensive screening, our study more objectively describes the prevalence and characteristics of the natural diabetic population over 60 years old in China.

Our study results show that each increase of 1 mmol/L in fasting blood glucose levels raises the probability of a high-risk foot condition by 4.8%. This finding is consistent with prior research indicating that poor glycemic control is a significant risk factor for diabetic foot (2, 22). However, other studies have noted that good glycemic control does not necessarily reduce the incidence of PAD (23). Additionally, we found that an increase in income level significantly correlates with an increased risk of foot complications. This may suggest that individuals with higher economic status may have more opportunities to engage in activities that increase the risk of foot complications, or it could reflect other unadjusted confounding factors. This was only a cross-sectional study, and the observed associations need to be confirmed by further research.

It is noteworthy that although hypertension is commonly considered a risk factor for cardiovascular diseases, in our study, we found that the prevalence of diabetic at-risk foot was lower in the hypertensive population, which may be explained by the following reasons: (1) Treatment and health management effects: Diabetic patients with hypertension received more frequent community follow-up, more standardized antihypertensive and hypoglycemic treatment, and better diabetes management adherence, which indirectly reduced at-risk foot risk, rather than hypertension itself having a protective effect; (2) Residual confounding: Unmeasured factors such as foot care awareness and self-management behavior may still exist despite multivariable adjustment; (3) Survivor bias: The study population was elderly patients aged ≥60 years, and hypertensive patients who survived and participated in the screening may have better overall health status and treatment adherence. Conversely, cardiovascular diseases and kidney diseases significantly increased the probability of high-risk foot conditions, consistent with previous studies indicating that these systemic diseases are associated with an increased risk of diabetic foot (24–26).

Most notably, the prevalence of diabetic at-risk foot in the population with peripheral neuropathy was 7.8 times that in the population without peripheral neuropathy. This finding underscores the importance of closely monitoring individuals with a history of conditions such as peripheral nerve compression or peripheral neuritis, as they play a significant role in the risk of diabetic foot. Numerous studies have been conducted on the relationship between Carpal Tunnel Syndrome (CTS) and diabetic peripheral neuropathy (DPN), showing consistent conclusions that DPN patients have an increased risk of developing CTS compared to diabetic patients without DPN (27–30), aligning with our findings. This highlights the indispensable role of understanding the history of peripheral neuropathic diseases in the foot risk assessment of diabetic patients.

It is noteworthy that although our results did not show a direct association between the duration of diabetes, retinopathy, and cataracts with an increased risk of diabetic foot, this does not imply that these factors are unimportant in diabetes management. Some studies have found that the occurrence of diabetic foot is related to factors such as the duration of diabetes, retinopathy, and cataracts (17, 31, 32), which may indirectly affect foot health through other mechanisms.

In summary, our study provides an in-depth understanding of the risk factors for diabetic foot and emphasizes the importance of comprehensive management strategies, including glycemic control, management of cardiovascular and kidney diseases, and early diagnosis and treatment of neuropathy. Future research should further explore how these risk factors affect foot health through specific mechanisms and how effective prevention strategies can reduce the incidence of diabetic foot.

Our study has several strengths and unique features, including multiple community health service centers, a broad sample population data, and a standardized team of examiners trained in diabetic foot screening, which ensures a high degree of homogeneity and representativeness in the results. However, our study has certain limitations. Firstly, our sample is limited to Xiamen, China, and the conclusions may not be generalizable to other regions. Secondly, our analysis population consists of diabetic individuals over 60 years old, and the conclusions may not be applicable to those under 60 years old. We emphasizing that the cross-sectional design cannot determine the temporal sequence between exposure and outcome, thus cannot support causal inference.