Diabetes and other vascular risk factors in association with the risk of lower extremity amputation in chronic limb-threatening ischemia: a prospective cohort study

Vitamin D and Risk of Incident Type 2 Diabetes in Older Adults: An Updated Systematic Review and Meta-Analysis

Vitamin D deficiency is very common worldwide, particularly in old age, when people are at the highest risk of the negative adverse consequences of hypovitaminosis D. Additionally to the recognized functions in the regulation of calcium absorption, bone remodeling, and bone growth, vitamin D plays a key role as a hormone, which is supported by various enzymatic, physiological, metabolic, and pathophysiological processes related to various human organs and systems. Accruing evidence supports that vitamin D plays a key role in pancreatic islet dysfunction and insulin resistance in type 2 diabetes. From an epidemiological viewpoint, numerous studies suggest that the growing incidence of type 2 diabetes in humans may be linked to the global trend of prevalent vitamin D insufficiency. In the past, this association has raised discussions due to the equivocal results, which lately have been more convincing of the true role of vitamin D supplementation in the prevention of incident type 2 diabetes. Most meta-analyses evaluating this role have been conducted in adults or young older persons (50-60 years old), with only one focusing on older populations, even if this is the population at greater risk of both hypovitaminosis D and type 2 diabetes. Therefore, we conducted an update of the previous systematic review and meta-analysis examining whether hypovitaminosis D (low serum 25OHD levels) can predict incident diabetes in prospective longitudinal studies among older adults. We found that low 25OHD was associated with incident diabetes in older adults even after adjusting for several relevant potential confounders, confirming and updating the results of the only previous meta-analysis conducted in 2017.

Patients living farther from a tertiary care center are more likely to undergo peripheral arterial bypass for acute and chronic limb-threatening ischemia

OBJECTIVE

The aim of this study was to assess the association between the proximity to the tertiary care hospital and the severity of peripheral arterial disease (PAD) at the time of lower extremity bypass (LEB) in a rural-urban mix region.

METHODS

Patients undergoing LEB from 2010 to 2020 at Penn State Milton S. Hershey Medical Center were reviewed and stratified into two study groups based on a median distance from hospital (ie, Group I: ≥34 miles and Group II: <34 miles). Patients' demographic features, preoperative data including comorbidities, and medications were analyzed. A univariate analysis for the patient characteristics between the two study groups, along with evaluation of postoperative outcomes, and a multivariate predictive modeling to study the PAD stage as the indication of LEB was performed. A P-value of < .05 was set as a significant difference between the groups for all the analyses.

RESULTS

There were 175 patients (49.9%) in Group I and 176 patients (50.1%) in Group II with a mean age of 65 ± 11.92 years (median, 64.61 years). No significant difference was observed in gender (P = .530), age (P = .906), and functional status (P = .830) between study groups. It was observed that patients in Group I were more likely to be overweight or obese (71.3% vs 57%; P = .007) and had a prior history of myocardial infarction (24.3% vs 15.3%; P = .036) in comparison to Group II. No postoperative outcomes were found to be statistically different between the study groups. The multivariate analyses based on various confounders displayed that patients in Group I had 56% higher likelihood of LEB for chronic limb-threatening ischemia (adjusted odds ratio, 1.56; 95% confidence interval, 0.92-2.62; P = .042). Group I patients also had five times higher odds of LEB for acute limb ischemia (adjusted odds ratio, 5.07; 95% confidence interval, 1.42-18.13; P = .012) as compared with those in the Group II.

CONCLUSIONS

Patients' proximity to a major tertiary hospital may have implications on the disease progression for patients with PAD and could also be related to inadequate vascular services in primary and secondary hospitals. Lack of preventive care and disease management in regions afar from a tertiary hospital could be other implicating factors and highlights the need for outreach programs, along with distribution of vascular specialists, to reduce geographical disparities and ensure equity in access to care.

Factors Associated With Early Amputation in Patients With Chronic Limb Threatening Ischemia

INTRODUCTION

Despite advancements in revascularization procedures, early amputation (EA) among patients with chronic limb threatening ischemia (CLTI) are still common. The present study evaluated clinical outcomes of patients with CLTI and factors associated with EA.

METHODS

The 2016-2019 Nationwide Readmission Database was queried to identify all adults (≥18 years) with CLTI of lower extremities undergoing limb salvage (LS) procedures. The primary outcome of the study was EA within 90 days of discharge. Secondary outcomes included infectious complication, length of stay (LOS), cumulative hospitalization cost and non-home discharge.

RESULTS

Of 103,703 patients who initially underwent surgical or endovascular revascularization, 10,439 (10.1%) subsequently underwent major amputation within 90 days of discharge. Following risk adjustment, factors associated with higher odds of EA were male sex, low-income quartile, tissue loss due to ulceration or gangrene, end-stage renal disease, and diabetes. Compared to those undergoing open revascularization, patients with endovascular limb salvage had a higher likelihood of having early amputation (AOR 1.41, 95% CI 1.31-1.51). Patients undergoing EA had greater odd of infectious complication, incremental LOS, incremental cost and non-home discharge.

CONCLUSIONS

We identified several risk factors to be associated with EA in patients with CLTI. These findings may supplement the objective performance goals for limb-related outcomes and facilitate institutional limb salvage programs.

Analysis of Lower Extremity Amputations from the SerbVasc Registry

BACKGROUND

Peripheral arterial disease (PAD) and diabetes are the major causes of lower extremity amputations (LEAs) worldwide. Morbidity and mortality in patients with LEAs are high with an associated significant burden on the global health system. The aim of this article is to report the overall morbidity and mortality rates after major and minor LEAs from the Serbian Vascular Registry (SerbVasc), with an analysis of predictive factors that influenced adverse outcomes.

MATERIALS AND METHODS

SerbVasc was created in 2019 as a part of the Vascunet collaboration that is aiming to include all vascular procedures from 21 hospitals in Serbia. Prevalence of diabetes among patients with LEAs, previous revascularization procedures, the degree and the type of foot infection and tissue loss, and overall morbidity and mortality rates were analyzed, with a special reference to mortality predictors.

RESULTS

In the period from January 2020 to December 2022, data on 702 patients with LEAs were extracted from the SerbVasc registry, mean age of 69.06±10.63 years. Major LEAs were performed in 59%, while minor LEAs in 41% of patients. Diabetes was seen in 65.1% of the patients, with 44% of them being on insulin therapy. Before LEA, only 20.3% of patients had previous peripheral revascularization. Soft tissue infection, irreversible acute ischemia, and Fontaine III and IV grade ischemia were the most common causes of above-the-knee amputations while diabetic foot was the most common cause of transphalangeal and toe amputations. The infection rate was 3.7%, the re-amputation rate was 5.7%, and the overall mortality rate was 6.9%, with intrahospital mortality in patients with above-the-knee amputation of 11.1%. The most significant intrahospital mortality predictors were age >65 years (p<0.001), chronic kidney disease (CKD) (p<0.001), ischemic heart disease (IHD) (p=0.001), previous myocardial revascularization (p=0.017), emergency type of admission (p<0.001), not using aspirin (p=0.041), using previous anticoagulation therapy (p=0.003), and postoperative complications (p<0.001).

CONCLUSIONS

The main predictors of increased mortality after LEAs from the SerbVasc registry are age >65 years, CKD, IHD, previous myocardial revascularization, emergency type of admission, not using aspirin, using previous anticoagulation therapy, and postoperative complications. Taking into account high mortality rates after LEAs and a small proportion of previous peripheral revascularization, the work should be done on early diagnosis and timely treatment of PAD hopefully leading to decreased number of LEAs and overall mortality.

CLINICAL IMPACT

Mortality after lower limb amputation from the SerbVasc register is high. A small number of previously revascularized patients is of particular clinical importance, bearing in mind that the main reasons for above-the-knee amputations were irreversible ischemia, Fontaine III and Fontaine IV grade ischemia. Lack of diagnostics procedures and late recognition of patients with PAD, led to subsequent threating limb ischemia and increased amputation rates. The work should be done on early diagnosis and timely treatment of PAD in Serbia, hopefully leading to an increased number of PAD procedures, decreased number of LEAs, and lower overall mortality.

A novel therapeutic management for diabetes patients with chronic limb-threatening ischemia: comparison of autologous bone marrow mononuclear cells versus allogenic Wharton jelly-derived mesenchymal stem cells

BACKGROUND

Chronic limb-threatening ischemia (CLTI) represents the final stage of peripheral arterial disease. Approximately one-third of patients with CLTI are not eligible for conventional surgical treatments. Furthermore, patients with advanced stage of CLTI are prone to amputation and death. Thus, an effective therapeutic strategy is urgently needed. In this context, autologous bone marrow mononuclear cell (auto-BM-MNC) and allogeneic mesenchymal stem cells represent a promising therapeutic approach for treating CLTI. In this study, we compared the safety and beneficial therapeutic effect of auto-BM-MNC versus allogeneic Wharton jelly-derived mesenchymal stem cells (allo-WJ-MSCs) in diabetic patients with CLTI.

METHODS

We performed a randomized, prospective, double-blind and controlled pilot study. Twenty-four diabetic patients in the advanced stage of CLTI (4 or 5 in Rutherford's classification) and a transcutaneous oxygen pressure (TcPO2) below 30 mmHg were randomized to receive 15 injections of (i) auto-BM-MNC (7.197 × 106 ± 2.984 × 106 cells/mL) (n = 7), (ii) allo-WJ-MSCs (1.333 × 106 cells/mL) (n = 7) or (iii) placebo solution (1 mL) (n = 10), which were administered into the periadventitial layer of the arterial walls under eco-Doppler guidance. The follow-up visits were at months 1, 3, 6, and 12 to evaluate the following parameters: (i) Rutherford's classification, (ii) TcPO2, (iii) percentage of wound closure, (iv) pain, (v) pain-free walking distance, (vi) revascularization and limb-survival proportion, and (vii) life quality (EQ-5D questionnaire).

RESULTS

No adverse events were reported. Patients with CLTI who received auto-BM-MNC and allo-WJ-MSCs presented an improvement in Rutherford's classification, a significant increase in TcPO2 values‬, a reduction in the lesion size in a shorter time, a decrease in the pain score and an increase in the pain-free walking distance, in comparison with the placebo group. In addition, the participants treated with auto-BM-MNC and allo-WJ-MSCs kept their limbs during the follow-up period, unlike the placebo group, which had a marked increase in amputation.

CONCLUSIONS

Our results showed that patients with CLTI treated with auto-BM-MNC and allo-WJ-MSCs conserved 100% of their limb during 12 months of the follow-up compared to the placebo group, where 60% of participants underwent limb amputation in different times. Furthermore, we observed a faster improvement in the allo-WJ-MSC group, unlike the auto-BM-MNC group. Trial registration This study was retrospectively registered at ClinicalTrials.gov (NCT05631444).

Potential metabolic biomarkers of critical limb ischemia in people with type 2 diabetes mellitus

INTRODUCTION

Type 2 diabetes mellitus (T2DM) is a significant risk factor for the development of critical limb ischemia (CLI), the most advanced stage of peripheral arterial disease. The concurrent existence of T2DM and CLI often leads to adverse outcomes, namely limb amputation.

OBJECTIVE

To identify biomarkers for improving the screening of CLI in high-risk people with T2DM.

METHODS

We investigated metabolome profiles in serum samples of 113 T2DM people with CLI (n = 23, G2) and without CLI (n = 45, G0: no lower limb stenosis (LLS) and n = 45, G1: LLS < 50%), using hydrogen nuclear magnetic resonance (¹H NMR) approach. Principle component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used to analyze ¹H NMR data.

RESULTS

Twenty potential metabolites that could discriminate people with T2DM and CLI (G2) from non-CLI patients without LLS (G0) were determined in serum samples. The correct percent of classification for the PLS-DA model for the test set samples was 85% (n = 20) and 100% (n = 5) for G0 and G2 groups, respectively. Non-CLI patients with LLS < 50% (G1) were projected on the PCA abstract space built using 20 discriminatory metabolites. Eleven people with T2DM and LLS < 50% were prospectively followed, and their ankle-brachial index (ABI) was measured after 4 years. A promising agreement existed between the PCA model's predictions and those obtained by ABI values.

CONCLUSION

The findings suggest that confirmation of blood potential metabolic biomarkers as a complement to ABI for screening of CLI in a large group of high-risk people with T2DM is needed.

Clinical Potential of Hydrogen Sulfide in Peripheral Arterial Disease

Peripheral artery disease (PAD) affects more than 230 million people worldwide. PAD patients suffer from reduced quality of life and are at increased risk of vascular complications and all-cause mortality. Despite its prevalence, impact on quality of life and poor long-term clinical outcomes, PAD remains underdiagnosed and undertreated compared to myocardial infarction and stroke. PAD is due to a combination of macrovascular atherosclerosis and calcification, combined with microvascular rarefaction, leading to chronic peripheral ischemia. Novel therapies are needed to address the increasing incidence of PAD and its difficult long-term pharmacological and surgical management. The cysteine-derived gasotransmitter hydrogen sulfide (H₂S) has interesting vasorelaxant, cytoprotective, antioxidant and anti-inflammatory properties. In this review, we describe the current understanding of PAD pathophysiology and the remarkable benefits of H₂S against atherosclerosis, inflammation, vascular calcification, and other vasculo-protective effects.

Focus on the Prevention of Acute Limb Ischemia: Centrality of the General Practitioner from the Point of View of the Internist

The thrombotic mechanism, being common to peripheral arterial disease (PAD), acute myocardial infarction (AMI), and stroke, is responsible for the highest number of deaths in the western world. However, while much has been done for the prevention, early diagnosis, therapy of AMI and stroke, the same cannot be said for PAD, which is a negative prognostic indicator for cardiovascular death. Acute limb ischemia (ALI) and chronic limb ischemia (CLI) are the most severe manifestations of PAD. They both are defined by the presence of PAD, rest pain, gangrene, or ulceration and we consider ALI if symptoms last less than 2 weeks and CLI if they last more than 2 weeks. The most frequent causes are certainly atherosclerotic and embolic mechanisms and, to a lesser extent, traumatic or surgical mechanisms. From a pathophysiological point of view, atherosclerotic, thromboembolic, inflammatory mechanisms are implicated. ALI is a medical emergency that puts both limb and the patient's life at risk. In patients over age 80 undergoing surgery, mortality remains high reaching approximately 40% as well as amputation approximately 11%. The purpose of this paper is to summarize the scientific evidence on the possibilities of primary and secondary prevention of ALI and to raise awareness among doctors involved in the management of ALI, in particular by describing the central role of the general practitioner.

Lower-limb peripheral arterial disease and amputations in people with diabetes: Risk factors, prognostic value and management

Lower-limb peripheral arterial disease (PAD), is a common manifestation of systemic atherosclerosis, resulting from a partial or complete obstruction of at least one lower-limb arteries. PAD is a major endemic disease with an excess risk of major cardiovascular events and death. It also leads to disability, high rates of lower-limb adverse events and non-traumatic amputation. In patients with diabetes, PAD is particularly frequent and has a worse prognosis than in patients without diabetes. The risk factors of PAD are comparable to those for cardiovascular disease. The ankle-brachial index is usually recommended to screen PAD despite its limited performance in patients with diabetes, affected by the presence of peripheral neuropathy, medial arterial calcification, incompressible arteries and infection. Toe brachial index and toe pressure emerge as alternative screening tools. The management of PAD requires strict control of cardiovascular risk factors including diabetes, hypertension and dyslipidaemia, the use of antiplatelet agents and lifestyle management, to reduce cardiovascular adverse events, but few randomized controlled trials have evaluated the benefits of these treatments in PAD. Several advances have been achieved in endovascular and surgical revascularization procedures, with obvious improvement in PAD prognosis. Further studies are required to increase our understanding of the pathophysiology of PAD and to evaluate the interest of different therapeutic strategies in the occurrence and progression of PAD in patients with diabetes. Here, we present a narrative and contemporary review to synthesize the key epidemiology findings, screening and diagnosis methods, and major therapeutic advances regarding PAD in patients with diabetes.

Temporal trends in patients with peripheral artery disease influenced by diabetes mellitus in Germany

INTRODUCTION

In patients with peripheral artery disease (PAD) the presence of diabetes mellitus (DM) is associated with higher morbidity and mortality. Because huge efforts are made to improve medical care of patients with DM including chronic disease programs, the aim of the present study was to investigate temporal trends regarding the clinical burden of DM on PAD patients within a 15-year observational period.

METHODS

We analyzed all patients hospitalized because of PAD between 2005 and 2019 in Germany stratified regarding DM.

RESULTS

Overall, 2 654 871 hospitalizations of PAD patients (865 823 with DM) were included. Hospitalizations based on PAD inclined from 142 778 in 2005 to 190 135 in 2019 (β 3956 per year; 95% confidence interval [CI] 3034-4878, p < .001) with simultaneous increase of hospitalizations of PAD patients with DM (2005: 41609 (29.1%) versus 2019: 65 302 (34.3%); β 2019 per year [95% CI 1593-2446], p < .001). Amputation rates (β -0.42 [95% CI -0.44 to -0.40]; p < .001) as well as in-hospital case-fatality rate (2005: 4.7%, 2019: 2.8%; β -0.64 [95% CI -0.69 to -0.59]; p < .001) decreased in diabetic PAD patients during the observational time. In spite of improved morbidity and mortality in the last years of the observational period, patients with DM still suffered from an increased risk for morbidity and mortality during the observational period compared to nondiabetic PAD patients.

CONCLUSIONS

Despite the progress in DM treatments, DM still was associated with an unfavorable clinical patient profile and remained a substantial risk factor for morbidity and mortality in hospitalized patients with PAD and DM in Germany between 2005 and 2019.

Real-world risk of lower-limb amputation associated with sodium-glucose cotransporter 2 inhibitors versus metformin: A propensity score-matched model analysis in Japan

AIMS/INTRODUCTION

We aimed to clarify the real-world risk of lower-limb amputation and identify factors related to increased risk in Japanese patients with type 2 diabetes using sodium-glucose cotransporter 2 inhibitors (SGLT2is).

MATERIALS AND METHODS

We carried out a retrospective observational cohort study utilizing the Japanese Medical Data Vision, a diagnosis procedure combination database. We identified 107,296 patients with type 2 diabetes who were initiated on SGLT2is or metformin (control; n = 53,648 per group) using 1:1 propensity score matching from April 2014 to October 2019. The hazard ratio (HR) for the risk of lower-limb amputation was analyzed using a Cox proportional hazards model adjusted for patients' baseline characteristics and use of concomitant medical agents.

RESULTS

Of the 107,296 patients, 66 (0.06%); that is, 41 (0.08%) in the SGLT2is group and 25 (0.05%) in the metformin group, underwent amputation, with no significant difference in the proportions between the groups. There was no significant difference in the risk of amputation between the SGLT2is and metformin groups (HR 1.34, 95% confidence interval [CI] 0.80-2.24). However, female sex (HR 2.78, 95% CI 1.12-6.94) and use of strong statins (HR 2.68; 95% CI 1.18-8.20) were significantly associated with a higher risk of amputation in the SGLT2is group than in the metformin group.

CONCLUSIONS

SGLT2is might not be related to an increased risk of lower-limb amputation in patients with type 2 diabetes in real-world clinical practice. The possible increased risk of SGLT2is-associated amputation in female patients with type 2 diabetes and patients with type 2 diabetes requiring strong statins is notable.

BAG3 Attenuates Ischemia-Induced Skeletal Muscle Necroptosis in Diabetic Experimental Peripheral Artery Disease

Peripheral artery disease (PAD) is characterized by impaired blood flow to the lower extremities, resulting in ischemic limb injuries. Individuals with diabetes and PAD typically have more severe ischemic limb injuries and limb amputations, but the mechanisms involved are poorly understood. Previously, we identified BAG3 as a gene within a mouse genetic locus termed limb salvage QTL1 on mouse chromosome 7 that determined the extent of limb necrosis following ischemic injury in C57Bl/6 mice. Whether BAG3 deficiency plays a role in the severe ischemic injury observed in diabetic PAD is not known. In vitro, we found simulated ischemia enhanced BAG3 expression in primary human skeletal muscle cells, whereas BAG3 knockdown increased necroptosis markers and decreased cell viability. In vivo, ischemic skeletal muscles from hind limbs of high-fat diet (HFD)-fed mice showed poor BAG3 expression compared to normal chow diet (NCD)-fed mice, and this was associated with increased limb amputations. BAG3 overexpression in ischemic skeletal muscles from hind limbs of HFD mice rescued limb amputation and improved autophagy, necroptosis, skeletal muscle function and regeneration. Therefore, BAG3 deficiency in ischemic skeletal muscles contributes to the severity of ischemic limb injury in diabetic PAD, likely through autophagy and necroptosis pathways.