Validation and comparison of currently available stratification systems for patients with diabetes by risk of foot ulcer development

External validation of the DIAFORA system to predict lower-extremity amputations in a prospective Danish cohort

AIM

A diabetes-related foot ulcer (DFU) is a major risk factor for lower-extremity amputation (LEA). To help clinicians predict the risk of LEA in people with DFU, the Diabetic Foot Risk Assessment (DIAFORA) system was developed but has never been externally validated.

METHODS

In this study, 317 people presenting with a new DFU were included. At baseline, participants were grouped into three groups based on their DIAFORA score: low-risk (<15), medium-risk (15-25), and high-risk (>25). Participants were followed until healing, LEA, death, or at least 3 months. Discriminative accuracy was evaluated using sensitivity, specificity, likelihood ratios (LRs) and the area under the curve (AUC).

RESULTS

All 317 participants completed at least 3 months of follow-up for a median duration of 146 days, during which 12.6% underwent minor amputation and 2.5% major amputation. People in the low- and medium-risk categories had major amputation rates of 0.9% and 2.1%, respectively, and negative LR of major LEA of 0.10 and 0.38, respectively, while the people in the high-risk category had an amputation rate of 25.0% and a positive LR of 12.9. The DIAFORA risk groups had a sensitivity of 75.0% and a specificity of 65.7%, with a corresponding AUC of 0.78 (95% CI 0.68-0.87) for the prediction of major LEA.

CONCLUSION

The DIAFORA score is a useful tool for risk stratification of people presenting with a newly occurred DFU, with the external validation presenting results similar to those presented in the original study. The DIAFORA score may guide clinicians towards more individualized DFU treatment regimens.

Prevalence of diabetic foot at risk of ulcer development and its components stratification according to the international working group on the diabetic foot (IWGDF): A systematic review with metanalysis

AIMS

To determine the overall prevalence of diabetic foot at risk according to the International Working Group on the Diabetic Foot stratification.

MATERIALS AND METHODS

We searched PubMed/Medline, Scopus, Web of Science, and Embase. We included cross-sectional studies or cohorts from 1999 to March 2022. We performed a meta-analysis of proportions using a random-effects model. We assessed heterogeneity through subgroup analysis by continent and other characteristics.

RESULTS

We included 36 studies with a total population of 11,850 people from 23 countries. The estimated overall prevalence of diabetic foot at risk was 53.2% (95% CI: 45.1-61.3), I2 = 98.7%, p < 0.001. In the analysis by subgroups, South and Central America had the highest prevalence and Africa the lowest. The factors explaining the heterogeneity were the presence of chronic kidney disease, diagnostic method for peripheral arterial disease, and quality. The estimates presented very low certainty of evidence.

CONCLUSIONS

The overall prevalence of diabetic foot at risk is high. The high heterogeneity between continents can be explained by methodological aspects and the type of population. However, using the same classification is necessary for standardization of the way of measuring the components, as well as better designed general population-based studies.

Predicting diabetic foot ulceration using routinely collected data in a foot clinic. What level of prognostic accuracy can be achieved?

This study aimed to investigate the efficacy of using routinely collected clinical data in predicting the risk of diabetic foot ulcer (DFU). The first objective was to develop a prognostic model based on the most important risk factors objectively selected from a set of 39 clinical measures. The second objective was to compare the prediction accuracy of the developed model against that of a model based on only the 3 risk factors that were suggested in the systematic review and meta-analyses study (PODUS). In a cohort study, a set of 12 continuous and 27 categorical data from patients (n = 203 M/F:99/104) who attended a specialised diabetic foot clinic were collected at baseline. These patients were then followed-up for 24 months during which 24 (M/F:17/7) patients had DFU. Multivariate logistic regression was used to develop a prognostic model using the identified risk factors that achieved p < 0.2 based on univariate logistic regression. The final prognostic model included 4 risk factors (Adjusted-OR [95% CI]; p) in total. Impaired sensation (116.082 [12.06-1117.287]; p = 0.000) and presence of callus (6.257 [1.312-29.836]; p = 0.021) were significant (p < 0.05), while having dry skin (5.497 [0.866-34.89]; p = 0.071) and Onychomycosis (6.386 [0.856-47.670]; p = 0.071) that stayed in the model were not significant. The accuracy of the model with these 4 risk factors was 92.3%, where sensitivity and specificity were 78.9%, and 94.0% respectively. The 78.9% sensitivity of our prognostic 4-risk factor model was superior to the 50% sensitivity that was achieved when the three risk factors proposed by PODUS were used. Also our proposed model based on the above 4 risk factors showed to predict the DFU with higher overall prognostic accuracy. These findings have implications for developing prognostic models and clinical prediction rules in specific patient populations to more accurately predict DFU.

Validation and application of the 2019 International Working Group on the Diabetic Foot risk stratification for diabetic foot in Chinese patients

AIMS/INTRODUCTION

The purpose of the present study was to evaluate the validation and application of the 2019 International Working Group on the Diabetic Foot (IWGDF) risk stratification system among Chinese patients with diabetes.

MATERIALS AND METHODS

A retrospective cohort study was carried out with 254 patients with diabetes, but without an active diabetic foot (DF) ulcer. Patients hospitalized from January to May 2017 were enrolled, and the follow-up period was from January to May 2020. Patients were stratified into four risk groups based on the 2019 IWGDF risk stratification system.

RESULTS

Of the 254 patients, four of 31 patients at risk 1 were diagnosed with DF within 3 years, whereas 12 of 26 patients at risk 2 and 16 of 20 patients at risk 3 developed DF. The area under the curve was 0.919 (P < 0.01, 95% confidence interval 0.893-0.945). Because DF risk 2 and greater (risk 2 + risk 3) was the optimal cut-off point, we simplified the risk stratification system by using two tiers, namely, low risk (risk 0 + 1) and high risk (risk 2 + 3). For the simplified risk stratification system, the sensitivity, specificity, positive likelihood ratio, percent agreement, positive predictive value and negative predictive value were 87.5%, 91.8%, 10.607, 91.3%, 60.8% and 98.1%, respectively. The χ² -test showed that the odds ratio of the high-risk group (risk 2 + 3) was 29.33-fold that of the low-risk group (risk 0 + 1).

CONCLUSIONS

The 2019 IWGDF risk stratification system showed high validity and primary screening value in Chinese patients with diabetes. Thus, a simplified, two-tiered IWGDF stratification might be more efficient and cost-effective for predicting DF ulcers.

Analysis of clinical phenotypes of neuropathic symptoms in patients with type 2 diabetes: A multicenter study

Aims/Introduction

We investigated the classification of diabetic peripheral neuropathy (DPN) patients by subjective symptoms, and identification of the relationship between the patterns and intensities of symptoms and the clustered groups of DPN patients.

Materials and Methods

This multicenter study analyzed epidemiological data and sensory symptoms of 649 patients with DPN. Cluster analysis was carried out to identify subgroups of patients with characteristic symptom profiles. Factor analysis was carried out to investigate the symptom patterns of the clustered groups of DPN patients.

Results

Three clusters of patients with DPN were identified: severe symptoms with decreased quality of life (cluster 1, n = 119, 18.3%), predominantly insensate symptoms with relatively good quality of life (cluster 2, n = 318, 49.0%), and moderate pain intensity and decreased quality of life (cluster 3, n = 204, 31.4%). The frequency of symptoms on each item of the Michigan Neuropathy Screening Instrument questionnaire showed a similar distribution according to pain intensities along with the three clusters.

Conclusions

Our study supports the hypothesis that diversity in sensory symptoms exists in patients with DPN. Heterogeneity in DPN patients should be taken into account for a more stratified or individualized treatment approach. Based on a multicenter study, we identified three clusters of patients with DPN. Our research supports the hypothesis that diversity in sensory symptoms exists in patients with DPN. Heterogeneity in DPN patients should be taken into account for a more stratified or individualized treatment approach.

Risk assessment and classification for foot ulceration among patients with type 2 diabetes in South Korea

AIM

This study aimed to investigate the distribution of foot conditions, the risk of foot ulceration and its associated factors in patients with diabetes. Few studies have focused on the risk of foot ulceration in patients with diabetes.

METHODS

A total of 267 patients with diabetes who attended outpatient clinics in two tertiary referral hospitals were recruited from June to September 2016. The risk of foot ulceration was classified using the American Diabetes Association (ADA), International Working Group on the Diabetic Foot (IWGDF) and Scottish Intercollegiate Guidelines Network (SIGN) classification systems. The risk categories of each system were reclassified into high- (categories of 2 and 3 for the ADA and IWGDF systems and high for the SIGN system) and low-risk.

RESULTS

Foot deformity was the most prevalent condition (38.2%). Among 261 patients without active ulcers, between 17.6% to 35.2% were classified in the high-risk group and overall agreement among systems ranged from .42 to .56 of the kappa statistic. Insulin treatment was consistently associated with a high-risk of foot ulceration.

CONCLUSIONS

As the risk varies between systems, nurses should select a suitable classification system through validation studies and assess the risk in patients with diabetes, particularly, those receiving insulin treatment.

Clinician Assessment Tools for Patients with Diabetic Foot Disease: A Systematic Review

The amputation rate in patients with diabetes is 15 to 40 times higher than in patients without diabetes. To avoid major complications, the identification of high-risk in patients with diabetes through early assessment highlights as a crucial action. Clinician assessment tools are scales in which clinical examiners are specifically trained to make a correct judgment based on patient outcomes that helps to identify at-risk patients and monitor the intervention. The aim of this study is to carry out a systematic review of valid and reliable Clinician assessment tools for measuring diabetic foot disease-related variables and analysing their psychometric properties. The databases used were PubMed, Scopus, SciELO, CINAHL, Cochrane, PEDro, and EMBASE. The search terms used were foot, ankle, diabetes, diabetic foot, assessment, tools, instruments, score, scale, validity, and reliability. The results showed 29 validated studies with 39 Clinician assessment tools and six variables. There is limited evidence on all of the psychometric characteristics of the Clinician assessment tools included in this review, although some instruments have been shown to be valid and reliable for the assessment of diabetic neuropathy (Utah Early Neuropathy Scale or UENS); ulceration risk (Queensland High Risk Foot Form or QHRFF); diabetic foot ulcer assessment, scoring, and amputation risk (Perfusion, extent, depth, infection and sensation scale or PEDIS and Site, Ischemia, Neuropathy, Bacterial Infection, and Depth score or SINBAD); and diabetic foot ulcer measurement (Leg Ulcer Measurement Tool LUMT).

Predicting the risk of future diabetic foot ulcer occurrence: a prospective cohort study of patients with diabetes in Tanzania

OBJECTIVES

The aim of this study was to identify the parameters that predict the risk of future foot ulcer occurrence in patients with diabetes.

RESEARCH DESIGN AND METHODS

1810 (male (M)/female (F): 1012/798) patients, with no foot ulcer at baseline, participated in this study. Data from a set of 28 parameters were collected at baseline. During follow-up, 123 (M/F: 68/55) patients ulcerated. Survival analyses together with logistic regression were used to identify the parameters that could predict the risk of future diabetic foot ulcer occurrence.

RESULTS

A number of parameters (HR (95% CI)) including neuropathy (2.525 (1.680 to 3.795)); history of ulceration (2.796 (1.029 to 7.598)); smoking history (1.686 (1.097 to 2.592)); presence of callus (1.474 (0.999 to 2.174)); nail ingrowth (5.653 (2.078 to 15.379)); foot swelling (3.345 (1.799 to 6.218)); dry skin (1.926 (1.273 to 2.914)); limited ankle (1.662 (1.365 to 2.022)) and metatarsophalangeal (MTP) joint (2.745 (1.853 to 4.067)) ranges of motion; and decreased (3.141 (2.102 to 4.693)), highly decreased (5.263 (1.266 to 21.878)), and absent (9.671 (5.179 to 18.059)) sensation to touch; age (1.026 (1.010 to 1.042)); vibration perception threshold (1.079 (1.060 to 1.099)); duration of diabetes (1.000 (1.000 to 1.000)); and plantar pressure at the first metatarsal head (1.003 (1.001 to 1.005)), temperature sensation (1.019 (1.004 to 1.035)) and temperature tolerance (1.523 (1.337 to 1.734)) thresholds to hot stimuli and blood sugar level (1.027 (1.006 to 1.048)) were all significantly associated with increased risk of ulceration. However, plantar pressure underneath the fifth toe (0.990 (0.983 to 0.998)) and temperature sensation (0.755 (0.688 to 0.829)) and temperature tolerance (0.668 (0.592 to 0.0754)) thresholds to cold stimuli showed to significantly decrease the risk of future ulcer occurrence. Multivariate survival model indicated that nail ingrowth (4.42 (1.38 to 14.07)); vibration perception threshold (1.07 (1.04 to 1.09)); dry skin status (4.48 (1.80 to 11.14)); and temperature tolerance threshold to warm stimuli (1.001 (1.000 to 1.002)) were significant predictors of foot ulceration risk in the final model. The mean time to ulceration was significantly (p<0.05) shorter for patients with: dry skin (χ²=11.015), nail ingrowth (χ²=14.688), neuropathy (χ²=21.284), or foot swelling (χ²=16.428).

CONCLUSION

Nail ingrowth and dry skin were found to be strong indicators of vulnerability of patients to diabetic foot ulceration. Results highlight that assessments of neuropathy in relation to both small and larger fiber impairment need to be considered for predicting the risk of diabetic foot ulceration.

Risk of diabetic foot ulcer and its associated factors among Bangladeshi subjects: a multicentric cross-sectional study

OBJECTIVE

To assess the risk of diabetic foot ulcer (DFU) and find out its associated factors among subjects with type 2 diabetes (T2D) of Bangladesh.

DESIGN, SETTING AND PARTICIPANTS

This cross-sectional study recruited 1200 subjects with T2D who visited 16 centres of Health Care Development Project run by Diabetic Association of Bangladesh.

PRIMARY AND SECONDARY OUTCOME MEASURES

Risk of DFU was assessed using a modified version of International Working Group on the Diabetic Foot (IWGDF) Risk Classification System. The modified system was based on five parameters, namely peripheral neuropathy (PN), peripheral arterial diseases (PAD), deformity, ulcer history and amputation. The risks were categorised as group 0 (no PN, no PAD), group 1 (PN, no PAD and no deformity), group 2A (PN and deformity, no PAD), group 2B (PAD), group 3A (ulcer history) and group 3B (amputation). The associated factors of DFU risk were determined using multinomial logistic regression for each risk category separately.

RESULTS

Overall, 44.5% of the subjects were found 'at risk' of DFU. This risk was higher among men (45.6%) than women and among those who lived in rural areas (45.5%) as compared with the urban population. According to IWGDF categories, the risk was distributed as 55.5%, 4.2%, 11.6%, 0.3%, 20.6% and 7.9% for group 0, group 1, group 2A, group 2B, group 3A and group 3B, respectively. The associated factors of DFU (OR >1) were age ≥50 years, rural area, low economic status, insulin use, history of trauma, diabetic retinopathy and diabetic nephropathy.

CONCLUSION

A significant number of the subjects with T2D under study were at risk of DFU, which demands an effective screening programme to reduce DFU-related morbidity and mortality.

Diabetic foot ulcer development risk classifications' validation: A multicentre prospective cohort study

AIMS

To prospectively validate the existing classifications to stratify subjects with diabetes mellitus (DM) by their risk of diabetic foot ulcer (DFU), in high and low risk settings.

METHODS

A prospective multicentre cohort study was conducted, including 446 subjects with DM without active DFU followed in the hospital or primary care setting. Demographic, clinical characterization variables, and those included in the classifications were collected at baseline. Subjects were followed for 1year, until DFU or death.

RESULTS

In our sample, with a mean age of 65years, 52% were male; 32 developed a DFU, 7 required an amputation and 18 died. Differences were found between participants' characteristics and classifications' accuracy according to the setting. The great majority of the variables were associated with higher DFU risk. Globally, classifications were highly and equally valid, positive predictive values (PV) were inferior to 40%, negative PV superior to 90% and area under the receiver operating characteristic curve superior to 0.75.

DISCUSSION

All the existing classifications are valid to be applied in high risk clinical context and have a very high capacity to categorize as low risk those subjects that will not develop a DFU. Further research is needed in the primary care setting.

A new diabetic foot risk assessment tool: DIAFORA

AIMS

This study aimed to derive a new model to classify subjects with diabetes and active diabetic foot ulcer by their risk of lower extremity amputation.

METHODS

A prospective cohort study was conducted that included all subjects with diabetic foot ulcer attending our Hospital Diabetic Foot Clinic from 2010 to 2013. Variables were collected at baseline. Subjects were followed up until healing, lower extremity amputation, death or for at least 3 months. Logistic regression was used to derive the new model, and the area under the receiver operating characteristic curve was assessed to propose the model with the greatest discrimination.

RESULTS

A total of 293 participants were included and followed for a median of 91 days. In 23.2% amputation was required, 5.1% died and 3.1% were lost. Our final model included the variables most commonly used in clinical practice for diabetic foot risk assessment (presence of neuropathy, foot deformity, peripheral arterial disease and previous foot complications) in addition to multiple diabetic foot ulcer, infection, gangrene and bone involvement. This model had an area under the receiver operating characteristic curve of 0.91 [95% confidence interval (CI) 0.87-0.95] and as classification of 0.89 (95% CI 0.84-0.93) for lower extremity amputation prediction. The high-risk group presented a positive likelihood ratio of 5 (95% CI 3-8) and predictive value of 58 (46-71). Only one minor lower extremity amputation occurred in the low-risk group.

CONCLUSIONS

We propose a new classification: diabetic foot risk assessment (DIAFORA). This classification was equally or more accurate for lower extremity amputation prediction in diabetic foot ulcer patients when compared with the existing ones.

Diabetic foot risk assessment

Diabetes is a serious chronic disease that results in foot complications for many people world-wide. In 2014, the World Health Organization estimated the global prevalence of diabetes in adults to be 9%. To ascertain the risk that an individual patient might develop a diabetic foot ulcer that could lead to an amputation, clinicians are strongly encouraged to perform a risk assessment. Monteiro-Soares and Dinis-Ribeiro have presented a new DIAbetic FOot Risk Assessment with the acronym DIAFORA. It is different from other risk assessments in that it predicts the risk of developing both diabetic foot ulcers and amputation specifically. The risk variables were derived by regression analysis based on a data set of 293 patients from a high-risk setting, a Hospital Diabetic Foot Clinic, who had diabetes and a diabetic foot ulcers. Clear descriptions of the risk variables are provided as well as sensitivity, specificity, positive and negative predictive values for the risk categories. As an added benefit, likelihood ratios are provided that will help clinicians determine the risk of amputation for individual patients. Having a risk assessment form is important for clinician use and examples exist. A question is raised about the effectiveness of risk assessment and how effectiveness might be determined.

Clinical decision support software for diabetic foot risk stratification: development and formative evaluation

Background

Identifying people at risk of developing diabetic foot complications is a vital step in prevention programs in primary healthcare settings. Diabetic foot risk stratification systems predict foot ulceration. The aim of this study was to explore the views and experiences of potential end users during development and formative evaluations of an electronic diabetic foot risk stratification tool based on evidence-based guidelines and determine the accuracy of the tool.

Methods

Formative evaluation of the risk tool occurred in five stages over an eight-month period and employed a mixed methods research design consisting of semi-structured interviews, focus group and participant observation, online survey, expert review, comparison to the Australian Guidelines and clinical testing.

Results

A total of 43 healthcare practitioners trialled the computerised clinical decision support system during development, with multiple software changes made as a result of feedback. Individual and focus group participants exposed critical design flaws. Live testing revealed risk stratification errors and functional limitations providing the basis for practical improvements. In the final product, all risk calculations and recommendations made by the clinical decision support system reflect current Australian Guidelines.

Conclusions

Development of the computerised clinical decision support system using evidence-based guidelines can be optimised by a multidisciplinary iterative process of feedback, testing and software adaptation by experts in modern development technologies.

Reliability and validity of the perfusion, extent, depth, infection and sensation (PEDIS) classification system and score in patients with diabetic foot ulcer

Aims

To validate the perfusion, extent, depth, infection and sensation (PEDIS) classification system and to make the clinical practice easier, we created a score system and compared this system with two previously published common score systems.

Methods

A retrospective cohort study was conducted on patients with diabetic foot ulcer (DFU) attending our hospital (n=364) from May 2007 to September 2013. Participants’ characteristics and all variables composing the PEDIS classification system were assessed.

Results

During a median follow-up of 25 months (range 6-82), ulcers healed in 217 of the 364 patients (59.6%), remained unhealed in 37 patients (10.2%), and were resolved by amputation in 62 patients (17.0%); 48 patients (13.2%) died. When measured using the PEDIS classification system, the outcome of DFU deteriorated with increasing severity of each subcategory. Additionally, longer ulcer history, worse perfusion of lower limb, a larger extent of the ulcer, a deeper wound, more severe infection, and loss of protective sensation were independent predictors of adverse outcome. More importantly, the new PEDIS score system showed good diagnostic accuracy, especially when compared with the SINBAD and Wagner score systems.

Conclusions

The PEDIS classification system, which encompasses relevant variables that contribute to the outcome of DFU and has excellent capacity for predicting the ulcer outcome, demonstrated acceptable accuracy. The PEDIS classification system might be useful in clinical practice and research both for the anticipation of health care costs and for comparing patient subgroups.

BE SMART: strategies for foot care and prevention of foot complications in patients with diabetes

BACKGROUND

Diabetic foot ulcers and lower extremity amputations are common complications of diabetes mellitus that are associated with substantial morbidity, loss of quality of life, disability, and a high social and economic burden. The implementation of strategies to prevent these complications is a key aspect of diabetes care.

OBJECTIVES

The objective of this article is to provide an overview of the available evidence on preventive diabetic foot care.

STUDY DESIGN

Literature review.

METHODS

Narrative review based on a thorough search of previous relevant studies, systematic reviews, and clinical guidelines on diabetic foot care published in English.

RESULTS

We describe diabetic foot care strategies that can be categorized within defined domains for the purpose of helping clinicians to remember them. We use the mnemonic "BE SMART" (Be aware of the risk factors, Educate patients and health providers, Structured clinical assessment, Metabolic evaluation and management, Assessment of Risk, and Team care) to organize these domains.

CONCLUSION

Diabetic foot ulcers and lower extremity amputations are potentially preventable complications. Clinicians taking care of patients with diabetes should know, understand, and remember the multiple aspects of diabetic foot care.

CLINICAL RELEVANCE

This review can be used as a reference source for those interested in the care of diabetic foot. It highlights the importance of risk factor recognition, education, a structured clinical and metabolic evaluation, and also the importance of assigning patients a risk category that can help guiding multidisciplinary management efforts.

Serum Uric Acid Levels and Diabetic Peripheral Neuropathy in Type 2 Diabetes: a Systematic Review and Meta-analysis

Previous studies suggested a possible association between serum uric acid levels and peripheral neuropathy in patients with type 2 diabetes, but no definite evidence was available. A systematic review and meta-analysis of relevant studies were performed to comprehensively estimate the association. Pubmed, Web of Science, Embase, and China Biology Medicine (CBM) databases were searched for eligible studies. Study-specific data were combined using random-effect or fixed-effect models of meta-analysis according to between-study heterogeneity. Twelve studies were finally included into the meta-analysis, which involved a total of 1388 type 2 diabetic patients with peripheral neuropathy and 4746 patients without peripheral neuropathy. Meta-analysis showed that there were obvious increased serum uric acid levels in diabetic patients with peripheral neuropathy (weighted mean difference [WMD] = 50.03 μmol/L, 95% confidence interval [95%CI] 22.14-77.93, P = 0.0004). Hyperuricemia was also significantly associated with increased risk of peripheral neuropathy in patients with type 2 diabetes (risk ratio [RR] = 2.83, 95%CI 2.13-3.76, P < 0.00001). Meta-analysis of two studies with adjusted risk estimates showed that hyperuricemia was independently associated with increased risk of peripheral neuropathy in type 2 diabetic patients (RR = 1.95, 95%CI 1.23-3.11, P = 0.005). Type 2 diabetic patients with peripheral neuropathy have obvious increased serum uric acid levels, and hyperuricemia is associated with increased risk of peripheral neuropathy. Further prospective cohort studies are needed to validate the impact of serum uric acid levels on peripheral neuropathy risk.