Prediction models for amputation after diabetic foot: systematic review and critical appraisal

BACKGROUND

Numerous studies have developed or validated prediction models aimed at estimating the likelihood of amputation in diabetic foot (DF) patients. However, the quality and applicability of these models in clinical practice and future research remain uncertain. This study conducts a systematic review and assessment of the risk of bias and applicability of amputation prediction models among individuals with DF.

METHODS

A comprehensive search was conducted across multiple databases, including PubMed, Web of Science, EBSCO CINAHL Plus, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang, Chinese Biomedical Literature Database (CBM), and Weipu (VIP) from their inception to December 24, 2023. Two investigators independently screened the literature and extracted data using the checklist for critical appraisal and data extraction for systematic reviews of prediction modeling studies. The Prediction Model Risk of Bias Assessment Tool (PROBAST) checklist was employed to evaluate both the risk of bias and applicability.

RESULTS

A total of 20 studies were included in this analysis, comprising 17 development studies and three validation studies, encompassing 20 prediction models and 11 classification systems. The incidence of amputation in patients with DF ranged from 5.9 to 58.5%. Machine learning-based methods were employed in more than half of the studies. The reported area under the curve (AUC) varied from 0.560 to 0.939. Independent predictors consistently identified by multivariate models included age, gender, HbA1c, hemoglobin, white blood cell count, low-density lipoprotein cholesterol, diabetes duration, and Wagner's Classification. All studies were found to exhibit a high risk of bias, primarily attributed to inadequate handling of outcome events and missing data, lack of model performance assessment, and overfitting.

CONCLUSIONS

The assessment using PROBAST revealed a notable risk of bias in the existing prediction models for amputation in patients with DF. It is imperative for future studies to concentrate on enhancing the robustness of current prediction models or constructing new models with stringent methodologies.

Are Thiol/Disulfide and 8-OHdG Levels in the Blood of Patients with Diabetic Foot a Risk Factor for Amputation?

OBJECTIVE

As diabetic patients live longer and there are more effective treatments available, the incidence of diabetes and its complications is increasing. The effects of oxidative stress and antioxidant processes on diabetes behavior, especially diabetic foot, are really direct. The goal of this research is to investigate the effects of oxidative stress and antioxidant mechanism on the outcome of amputation by examining the levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and thiol/disulfide in the blood of patients diagnosed with diabetic foot.

METHODS

The research consisted of 76 patients with type 2 diabetes with associated diabetic foot, ages 40-65 (51 men, 25 women). Patients with diabetic foot wounds and accompanying peripheral artery disease were not included in the study. After a mean follow-up of 9.6 months, 28 patients resulted in amputation. Between patients who required amputation and those who did not, the levels of 8-OHdG, native thiol, total thiol, disulfide, native thiol/total thiol ratio, disulfide/native thiol ratio, and disulfide/total thiol ratio were compared. Additionally, the age, sex, Wagner stage, and amputation outcome of these 2 patient groups were compared.

RESULTS

The outcomes of amputation in diabetic foot patients were not related to the levels of native thiol, total thiol, disulfide, native thiol/total thiol ratio, disulfide/native thiol ratio, total thiol/disulfide ratio, or 8-OHdG (P > .05). However, patients with diabetic foot who were male, older, and at a more advanced Wagner stage had a higher rate of amputations (P < .05).

CONCLUSION

Oxidative stress and antioxidant mechanism are effective on diabetes complications. However, since there are many factors affecting the outcome of amputation, they are not directly effective in terms of resulting amputation in patients with diabetic foot ulcer.

Time trends (2001-2019) and sex differences in incidence and in-hospital mortality after lower extremity amputations among patients with type 1 diabetes in Spain

Background

We examined trends in incidence (2001–2019), clinical characteristics, and in-hospital outcomes following major and minor lower extremity amputations (LEAs) among type 1 diabetes mellitus (T1DM) patients in Spain and attempted to identify sex differences.

Methods

Retrospective cohort study using data from the Spanish National Hospital Discharge Database. We estimated the incidence of the LEA procedure stratified by type of LEA. Joinpoint regression was used to estimate incidence trends, and logistic regression was used to estimate factors associated with in-hospital mortality (IHM).

Results

LEA was coded in 6011 patients with T1DM (66.4% minor and 33.6% major). The incidence of minor LEA decreased by 9.55% per year from 2001 to 2009 and then increased by 1.50% per year, although not significantly, through 2019. The incidence of major LEA decreased by 13.39% per year from 2001 to 2010 and then remained stable through 2019. However, incidence increased in men (26.53% per year), although not significantly, from 2017 to 2019. The adjusted incidence of minor and major LEA was higher in men than in women (IRR 3.01 [95% CI 2.64–3.36] and IRR 1.85 [95% CI 1.31–2.38], respectively). Over the entire period, for those who underwent a minor LEA, the IHM was 1.58% (2.28% for females and 1.36% for males; p = 0.045) and for a major LEA the IHM was 8.57% (10.52% for females and 7.59% for males; p = 0.025).

IHM after minor and major LEA increased with age and the presence of comorbid conditions such as peripheral arterial disease, ischemic heart disease or chronic kidney disease. Female sex was associated with a higher IHM after major LEA (OR 1.37 [95% CI 1.01–1.84]).

Conclusions

Our data show a decrease in incidence rates for minor and major LEA in men and women with T1DM and a slight, albeit insignificant, increase in major LEA in men with T1DM in the last two years of the study. The incidence of minor and major LEA was higher in men than in women. Female sex is a predictor of IHM in patients with T1DM following major LEA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01502-y.

Trends of Non-Traumatic Lower-Extremity Amputation and Type 2 Diabetes: Spain, 2001-2019

(1) Background: To examine trends in the incidence (2001–2019), clinical characteristics and in-hospital outcomes following major and minor non-traumatic lower-extremity amputations (LEAs) among people with type 2 diabetes mellitus (T2DM) in Spain, assessing possible sex differences. (2) Methods: Retrospective cohort study using data from the Spanish National Hospital Discharge Database. Joinpoint regression was used to estimate incidence trends, and multivariable logistic regression to estimate factors associated with in-hospital mortality (IHM). (3) Results: LEA was coded in 129,059 patients with T2DM (27.16% in women). Minor LEAs accounted for 59.72% of amputations, and major LEAs comprised 40.28%. The adjusted incidences of minor and major LEAs were higher in men than in women (IRR 3.51; 95%CI 3.46–3.57 and IRR 1.98; 95%CI 1.94–2.01, respectively). In women, joinpoint regression showed that age-adjusted incidence of minor LEAs remained stable over time, and for major LEAs, it decreased from 2006 to 2019. In men, incidences of minor and major LEAs decreased significantly from 2004 to 2019. In-hospital mortality (IHM) increased with age and the presence of comorbidity, such as heart failure (OR 5.11; 95%CI 4.61–5.68, for minor LEAs and OR 2.91; 95%CI 2.71–3.13 for major LEAs). Being a woman was associated with higher IHM after minor and major LEA (OR 1.3; 95%CI 1.17–1.44 and OR 1.18; 95%CI 1.11–1.26, respectively). (4) Conclusions: Our data showed major sex differences indicating decreasing and increasing LEA trends among men and women, respectively; furthermore, women presented significantly higher IHM after minor and major LEA procedures than men.

Sodium-Glucose Cotransporter 2 (SGLT2) Inhibitors vs. Dipeptidyl Peptidase-4 (DPP4) Inhibitors for New-Onset Dementia: A Propensity Score-Matched Population-Based Study With Competing Risk Analysis

Introduction: The effects of sodium-glucose cotransporter 2 inhibitors (SGLT2I) and dipeptidyl peptidase-4 inhibitors (DPP4I) on new-onset cognitive dysfunction in type 2 diabetes mellitus remain unknown. This study aimed to evaluate the effects of the two novel antidiabetic agents on cognitive dysfunction by comparing the rates of dementia between SGLT2I and DPP4I users.

Methods: This was a population-based cohort study of type 2 diabetes mellitus patients treated with SGLT2I and DPP4I between January 1, 2015 and December 31, 2019 in Hong Kong. Exclusion criteria were <1-month exposure or exposure to both medication classes, or prior diagnosis of dementia or major neurological/psychiatric diseases. Primary outcomes were new-onset dementia, Alzheimer's, and Parkinson's. Secondary outcomes were all-cause, cardiovascular, and cerebrovascular mortality.

Results: A total of 13,276 SGLT2I and 36,544 DPP4I users (total n = 51,460; median age: 66.3 years old [interquartile range (IQR): 58–76], 55.65% men) were studied (follow-up: 472 [120–792] days). After 1:2 matching (SGLT2I: n = 13,283; DPP4I: n = 26,545), SGLT2I users had lower incidences of dementia (0.19 vs. 0.78%, p < 0.0001), Alzheimer's (0.01 vs. 0.1%, p = 0.0047), Parkinson's disease (0.02 vs. 0.14%, p = 0.0006), all-cause (5.48 vs. 12.69%, p < 0.0001), cerebrovascular (0.88 vs. 3.88%, p < 0.0001), and cardiovascular mortality (0.49 vs. 3.75%, p < 0.0001). Cox regression showed that SGLT2I use was associated with lower risks of dementia (hazard ratio [HR]: 0.41, 95% confidence interval [CI]: [0.27–0.61], P < 0.0001), Parkinson's (HR:0.28, 95% CI: [0.09–0.91], P = 0.0349), all-cause (HR:0.84, 95% CI: [0.77–0.91], P < 0.0001), cardiovascular (HR:0.64, 95% CI: [0.49–0.85], P = 0.0017), and cerebrovascular (HR:0.36, 95% CI: [0.3–0.43], P < 0.0001) mortality.

Conclusions: The use of SGLT2I is associated with lower risks of dementia, Parkinson's disease, and cerebrovascular mortality compared with DPP4I use after 1:2 ratio propensity score matching.

The impact of gender on diabetes-related lower extremity amputations: An Italian regional analysis on trends and predictors

BACKGROUND

Diabetes-related lower extremity amputations (LEAs) are a major public health issue. The aim of the study was to evaluate trends by gender and predictors of LEAs in an Italian region.

METHODS

Data were collected from hospital discharge records between 2006 and 2015. Gender- and age-adjusted standardised hospitalisation rates for major and minor amputations were calculated. Poisson regression model was performed to estimate trends in LEAs.

RESULTS

Hospitalisation rates decreased for minor amputations both among males (-30.0%) and females (-5.3%), while the major amputation rates decreased only for males (-44.7%). Males were at higher risk of undergoing major (IRR 1.41, 95%CI 1.19-1.67) and minor (IRR 1.62, 95%CI 1.45-1.82) amputations. Peripheral vascular disease was the leading predictor of major and minor amputations.

CONCLUSION

A significant reduction of LEAs was observed only for males. Identifying their predictable factors may help caregivers to provide higher standards of diabetes care.

Active smoking is associated with higher rates of incomplete wound healing after endovascular treatment of critical limb ischemia

The association between active smoking and wound healing in critical limb ischemia (CLI) is unknown. Our objective was to examine in a retrospective cohort study whether active smoking is associated with higher incomplete wound healing rates in patients with CLI undergoing endovascular interventions. Smoking status was assessed at the time of the intervention, comparing active to no active smoking, and also during follow-up visits at 6 and 9 months. Cox regression analysis was conducted to compare the incomplete wound healing rates of the two groups during follow-up. A total of 264 patients (active smokers: n = 41) were included. Active smoking was associated with higher rates of incomplete wound healing in the 6-month univariate Cox regression analysis (hazard ratio (HR) for incomplete wound healing: 4.54; 95% CI: 1.41-14.28; p = 0.012). The 6-month Kaplan-Meier (KM) estimates for incomplete wound healing were 91.1% for the active smoking group versus 66% for the non-current smoking group. Active smoking was also associated with higher rates of incomplete wound healing in the 9-month univariable (HR for incomplete wound healing: 2.32; 95% CI: 1.11-4.76; p = 0.026) and multivariable analysis (HR for incomplete wound healing: 9.09; 95% CI: 1.06-100.0; p = 0.044). The 9-month KM estimates for incomplete wound healing were 75% in the active smoking group versus 54% in the non-active smoking group. In conclusion, active smoking status at the time of intervention in patients with CLI is associated with higher rates of incomplete wound healing during both 6- and 9-month follow-up.

[Clinical study of local injection of autologous platelet-rich plasma in treatment of diabetic foot ulcer]

OBJECTIVE

To investigate the effectiveness of local injection of autologous platelet-rich plasma (PRP) in treatment of diabetic foot ulcer.

METHODS

Between October 2017 and October 2018, 90 diabetic foot ulcer patients who met the selection criteria were randomly divided into 3 groups: PRP injection group (group A, PRP was injected and hydrogel dressing covered the wounds), PRP covered group (group B, PRP gel and hydrogel dressing covered the wounds), and the control group (group C, hydrogel dressing covered the wounds), 30 cases in each group. There was no significant difference in gender, age, injured side, disease duration, preoperative glycosylated hemoglobin, wound size, and Wagner grading between groups (P>0.05). The frequency of treatments and hospitalization day in all groups and the total amount of PRP application in groups A and B were recorded. The wound healing condition was recorded during the treatment, and the wound healing rate was calculated at 3 months after the first debridement.

RESULTS

The frequency of treatments in groups A, B, and C were (10.2±0.8), (11.4±0.6), (12.5±0.5) times, respectively. The total amount of PRP application of groups A and B were (306±24) and (342±18) mL, respectively. There was no significant difference in the frequency of treatments and the total amount of PRP application between groups (P>0.05). The hospitalization days of groups A, B, and C were (40.5±1.8), (62.1±2.3), and (88.6±1.4) days, respectively, showing significant differences between groups (P<0.05). In the course of treatment, the necrosis and exudation of the wounds gradually reduced, the areas of wounds gradually reduced; and the above conditions of group A were significantly better than groups B and C, and group B was better than group C. At 3 months after the first debridement, the wound healing rates of groups A, B, and C were 93.2%±0.8%, 52.1%±1.1%, and 21.3%±1.3%, respectively, with significant differences between groups (P<0.05).

CONCLUSION

PRP can effectively promote the repair of diabetic foot ulcer. The effectiveness of local injection of PRP is superior to the local coverage.

Canagliflozin and Amputation Risk: Evidence So Far

The CANVAS program detected a 2-fold increased risk of lower limb amputation in patients treated with canagliflozin compared with those with placebo. This adverse effect was not confirmed in the CREDENCE trial. Moreover, randomized controlled trials with other agents in this class, dapagliflozin and empagliflozin, did not detect increased risk of amputation. Observational studies, cohort studies, and pharmacovigilance reports with sodium-glucose cotransporter 2 inhibitor (SGLT2i) have reported conflicting results. Whether this adverse event is a drug effect specific to canagliflozin, or a SGLT2i class effect, remains controversial. Until more evidence emerges, clinicians should avoid using SGLT2i, especially canagliflozin, in patients with previous amputations or existing foot ulceration.

Vacuum-assisted closure versus moist dressings in the treatment of diabetic wound ulcers after partial foot amputation: A retrospective analysis in 65 patients

PURPOSE

Changes in weight-bearing patterns after partial foot amputations may lead to new localized high-pressure points and keratosis due to ulcerations in patients with neuropathies and hypovascular limbs. As a result, diabetic foot ulcers (DFUs) after partial foot amputations are very complex. The aim of this study was to compare the effectiveness of vacuum-assisted closure (VAC) therapy with conventional moist wound dressings in the treatment of diabetic wound ulcers after partial foot amputations.

METHODS

Sixty-five diabetic patients with a DFU, who had previously undergone partial foot amputation surgery, were assigned to treatment with VAC (group A: 31 patients) or conventional wound moist dressing (group B: 34 patients). The final results were considered as failed treatment if reamputation was required. Conversely, reaching 90% of wound granulation was considered to be a successful endpoint.

RESULTS

The average time to reach 90% granulation tissue was significantly lower in group A (7.8 ± 1.2 weeks vs. 11.1 ± 1.2 weeks; p < 0.001). However, there was no significant difference regarding the reamputation requirements; 38.7% (12 patients) in group A and 41.2% (14 patients) in group B, ( p = 0.839).

CONCLUSION

The results of this study allowed us to conclude that VAC therapy system appears to be an effective treatment for patients with complex DFUs who had previously undergone partial foot amputation.

Time Trends in the Incidence of Long-Term Mortality in T2DM Patients Who Have Undergone a Lower Extremity Amputation. Results of a Descriptive and Retrospective Cohort Study

(1) Background: The aims of this study were to examine the incidence of lower extremity amputations (LEAs) among patients with type 2 diabetes mellitus (T2DM) and to compare the mortality risk of diabetic individuals who underwent LEA with age and sex-matched diabetic individuals without LEA. (2) Methods: We performed a descriptive observational study to assess the trend in the incidence of LEA and a retrospective cohort study to evaluate whether undergoing LEA is a risk factor for long-term mortality among T2DM patients. Data were obtained from the Hospital Discharge Database for the Autonomous Community of Madrid, Spain (2006–2015). (3) Results: The incidence rates of major below-knee and above-knee amputations decreased significantly from 24.9 to 17.1 and from 63.9 to 48.2 per 100000 T2DM individuals from 2006 to 2015, respectively. However, the incidence of minor LEAs increased over time. Mortality was significantly higher among T2DM patients who underwent LEA compared with those who did not undergo this procedure (HR 1.75; 95% CI 1.65–1.87). Male sex, older age, and comorbidity were independently associated with higher mortality after LEA. (4) Conclusions: Undergoing a LEA is a significant risk factor for long term mortality among T2DM patients, and those who underwent a major above-knee LEAs have the highest risk.

Amputations in patients with diabetic foot ulcer: a retrospective study from a single centre in the Northern Territory of Australia

BACKGROUND

Lower extremity amputations (LEAs) in diabetic patients are common in the indigenous population. There is no published data from the Northern Territory.

METHODS

All patients with diabetic foot ulcer, presenting for the first time to the multi-disciplinary foot clinic at Royal Darwin Hospital, between January 2003 and June 2015, were included. These patients were followed until 2017, or death. LEA rates over the follow-up period and the risk factors were studied.

RESULTS

Of the 513 included patients, 62.8% were males and 48.2% were indigenous. The majority (93.6%) had type 2 diabetes with median diabetes duration of 7.0 years (interquartile range 3-12). During the follow-up period of 5.8 years (interquartile range 3.1-9.8), a total of 435 LEAs (16.6% major; 34.7% minor) occurred in 263 patients (mean age 57.0 ± 11.8 years). In multivariate analysis, the following variables were associated with LEAs (adjusted odds ratio (95% confidence interval)): prior LEA (4.49 (1.69-11.9)); peripheral vascular disease (2.67 (1.27-5.59)); forefoot ulcer (7.72 (2.61-22.7)); Wagner grade 2 (3.71 (1.87-7.36)); and Wagner grade 3 (17.02 (3.77-76.72)). Indigenous patients were 1.8 times more likely to have LEAs than non-indigenous patients. Indigenous amputees were approximately 9 years younger than their non-indigenous counterparts.

CONCLUSION

Half of patients presenting with diabetic foot ulcer had LEA during follow-up. Prior LEAs, peripheral vascular disease, forefoot ulcers and higher Wagner grades were independent risk factors for LEA. Indigenous patients were at higher risk for LEAs and were younger at the time of amputation.

Patients' clinical charecteristics and predictors for diabetic foot amputation

INTRODUCTION

Medical and surgical treatment options are available for patients with diabetic foot ulcers. In more severe cases, amputation decisions are determined by patient comorbidities, performance, imaging studies, and clinical examination results. However, an objective indicator that predicts how this amputation process will end has not yet been clarified. This study identifiies clinical characteristics that can be predictors of the need for diabetic foot amputation among patients.

METHODS

In this retrospective observational study, a total of 400 patients with type 2 diabetes who were over the age of 18 and possessed diabetic foot ulcers were examined. The clinical, radiological, and scintigraphic profiles of these patients including age, gender, duration of diabetes, smoking history, previous diabetic foot amputation, presence of hypertension (HT), coronary artery disease (CAD), peripheral artery disease (PAD), cerebrovascular disease, cardiovascular disease, retinopathy, neuropathy and nephropathy were analyzed.

RESULTS

Of the 400 patients with diabetic foot ulcers, 143 (35.75%) underwent foot amputation. Moreover, the frequency of proteinuria in amputees was significantly higher than in non-amputees (p<0,05). Amputees also exhibited significantly longer smoking histories (p<0,001), and the frequency of reamputation was significantly higher in those who possesed histories of previous amputation (p=0.038). After multivariate analysis PAD presence and previous diabetic ulcer history were the significant factors to determine the amputation decision.

CONCLUSION

The following patient characteristics were determined as being effective for predicting the need for amputation: male sex, CAD, PAD, HT, proteinuria, ulcers with Wagner Stages 4-5, smoking histories, previous diabetic ulcer histories, and previous amputation histories. The specificity of the model with these variables was determined as 86% in the patients who did not need amputation. Significant determinants were peripheral artery disease presence and diabetic foot ulcer history. Still, further and more extensive research with higher numbers of patients is necessary for determining more precisely the need for amputation.

Augmented contractility of murine femoral arteries in a streptozotocin diabetes model is related to increased phosphorylation of MYPT1

Diabetes mellitus (DM) is a metabolic disorder with high prevalence, and a major risk factor for macro- and microvascular abnormalities. This study was undertaken to explore the mechanisms of hypercontractility of murine femoral arteries (FA) obtained from mice with streptozotocin (STZ)-induced diabetes and its relation to the phosphorylation profile of the myosin phosphatase target subunit 1, MYPT1. The immunoreactivity of MYPT1 toward phospho-MYPT1-T696, MYPT1-T853, or MYPT1-S695, used as a read out for MYPT1 phosphorylation, has been studied by Western Blotting. Contractile activity of FA from control and STZ mice has been studied by wire myography. At basal conditions (no treatment), the immunoreactivity of MYPT1-T696/T853 was ~2-fold higher in the STZ arteries compared with controls. No changes in MYPT1-T696/853 phosphorylation were observed after stimulation with the Thromboxan-A2 analog, U46619. Neither basal nor U46619-stimulated phosphorylation of MYPT1 at S695 was affected by STZ treatment. Mechanical distensibility and basal tone of FA obtained from STZ animals were similar to controls. Maximal force after treatment of FA with the contractile agonists phenylephrine (10 μmol/L) or U46619 (1 μmol/L) was augmented in the arteries of STZ mice by ~2- and ~1.5-fold, respectively. In summary, our study suggests that development of a hypercontractile phenotype in murine FA in STZ diabetes is at least partially related to an increase in phosphorylation of MLCP at MYPT1-T696/853. Interestingly, the phosphorylation at S695 site was not altered in STZ-induced diabetes, supporting the view that S695 may serve as a sensor for mechanical activity which is not directly involved in tone regulation.

To Smoke or Not To Smoke: Cigarettes Have a Negative Effect on Wound Healing of Diabetic Foot Ulcers

Diabetic foot ulcers (DFUs) have a complex pathophysiology and require an expert multidisciplinary treatment. There are several, both systemic and local, risk factors for DFUs. A recent meta-analysis of 18 studies has now provided robust evidence on the detrimental effect of smoking on healing of DFUs. Indeed, healing rates were consistently lower among smokers than among nonsmokers. Based on this new evidence, it is reasonable to consider the utility of smoking cessation programs. Incorporation of the latter into the holistic therapeutic strategy for DFUs may be anticipated to improve healing rates, but this remains to be shown.

Association Between Cigarette Smoking and Diabetic Foot Healing: A Systematic Review and Meta-Analysis

The role of smoking for wound healing in patients with diabetic foot has been unclear. This meta-analysis examined the relationship between cigarette smoking and diabetic foot wound healing. Observational studies for the association between smoking and diabetic foot wound healing of patients were systematically searched through PubMed and Wanfang Data, published up to June 2018. Healing rates of wounds were recognized as outcomes. Meta-analysis models were chosen by heterogeneity. A total of 3388 eligible studies were identified, of which 18 met all our inclusion criteria. In the smoking group, healing rate had an average of 62.1%, ranging from 20.0% to 89.6%; in the nonsmoking group, healing rate had an average of 71.5%, ranging from 40.2% to 93.8%. A significant association was found between smoking and the healing of diabetic foot wounds ( z = 3.08; P = .002), with an odds ratio (OR) of 0.70 (95% CI = 0.56-0.88), based on a random-effects model. Meta-regression analyses indicated that the heterogeneity did not come from publication year ( t = -0.50, P = .622) or overall healing rate ( t = 0.16, P = .872). The leave-one-out sensitivity analysis was robust; sensitivity analysis for pooled estimate of adjusted ORs had an OR of 0.20 (95% CI = 0.07-0.56; z = 3.08; P = .002). Subgroup analysis had an OR of 0.62 (95% CI = 0.41-0.95; z = 2.21; P = .027) in retrospective cohort studies and had an OR of 0.75 (95% CI = 0.57-0.99; z = 2.02; P = .043) in prospective cohort studies. Our meta-analysis indicated that smoking had an overall negative effect on the wound healing of diabetic foot individuals. This study provides evidence for the harm of smoking to diabetic foot and may help reduce the medical and economic burden on poor healing of diabetic foot.