Heart rate-corrected QT interval prolongation as a prognostic marker for 3-year survival in people with Type 2 diabetes undergoing above-ankle amputation

Association between corrected QT interval and long-term cardiovascular outcomes in elderly patients who had undergone endovascular therapy for lower extremity arterial disease

Background

Population-based studies have reported the association between prolonged corrected QT (QTc) intervals and an increased risk of adverse cardiovascular events. Data regarding the association between longer QTc intervals and incident cardiovascular outcomes in patients with lower extremity arterial disease (LEAD) are scarce.

Objective

To examine the impact of QTc interval on long-term cardiovascular outcomes in elderly patients with symptomatic LEAD.

Methods

This cohort study extracted data from the Tzu-chi Registry of ENDovascular Intervention for Peripheral Artery Disease (TRENDPAD) and enrolled 504 patients aged ≥ 70 treated with endovascular therapy for atherosclerotic LEAD from July 1, 2005, to December 31, 2019. The main outcomes of interest were all-cause mortality and major adverse cardiovascular events (MACE). Multivariate analysis was conducted using the Cox proportional hazard model to determine independent variables. We performed interaction analysis between corrected QT and other covariates and Kaplan-Meier analysis to compare the outcome of interest among the groups stratified by the tercile of QTc intervals.

Results

A total of 504 patients [235 men (46.6%); mean age, 79.9 ± 6.2 years; mean QTc interval, 459 ± 33 msec] entered the final data analysis. We categorized the baseline patient characteristics according to terciles of QTc intervals. During the median follow-up time of 3.15 (interquartile ranges, 1.65-5.42) years, we noted 264 deaths and 145 MACEs. The 5-year rates of freedom from all-cause mortality (71% vs. 57% vs. 31%, P < 0.001) and MACEs (83% vs. 67% vs. 46%, P < 0.001) were significantly different among the tercile groups. Multivariate analysis showed that a 1-SD increase in the QTc interval increased the risk of all-cause mortality [hazard ratio (HR) 1.49, P < 0.001] and MACEs (HR 1.59, P < 0.001) after adjusting for other covariates. The interaction analysis showed that QTc interval and C-reactive protein levels were most strongly associated with death (HR = 4.88, 95% CI 3.09-7.73, interaction P < 0.001) and MACEs (HR = 7.83, 95% CI 4.14-14.79, interaction P < 0.001).

Conclusions

In elderly patients with symptomatic atherosclerotic LEAD, a prolonged QTc interval is associated with advanced limb ischemia, multiple medical comorbidities, increased risk of MACEs, and all-cause mortality.

Cardiometabolic risk factors and electrocardiogram results in type 2 diabetes patients with or without non-infected foot ulcers: A comparative study

BACKGROUND: Numerous investigations have demonstrated that type-2 diabetes (T2D) causes electrocardiographic alterations, whether or not there are microvascular or macrovascular problems.

AIM: With respect to glycemic control and the accompanying cardio-metabolic risk factors, the goal of this study was to demonstrate the variations in electrocardiogram records between T2D patients with non-infected diabetic foot ulcers (DFUs) and those without ulcers.

METHODS: This study was performed in the Shar Teaching Hospital in the Sulaimani Governorate-Iraq from July 2018 to June 2019. 167 participants were grouped into Group I (T2D, n=72); Group II (T2D with non-infected diabetic foot ulcers, n=65) and Group III (healthy subjects, n= 30). Blood pressure, electrocardiography, and anthropometric measurements were taken. Fasting serum glucose and lipid profiles were assessed as part of laboratory tests.

RESULTS: Group II patients significantly differed from Group I by having lower diastolic blood pressure, a higher pulse pressure index, and a higher fasting serum glucose. The Group I patients had a significantly higher heart rate, a shortening of TQ-interval and widening of QRS dispersion. Group II patients had a significantly shorter TQ-interval compared with the corresponding value of Group I patients (523.6±136.4ms versus 579.2±110.0ms, respectively). These changes in the electrocardiograms are not related to the cardiometabolic risk factors.

CONCLUSION: In the non-infected diabetic foot, the TQ-interval, a measure of ventricular repolarization impairment, is much shorter and is linked to a broad pulse pressure. According to this finding, the electrocardiographic abnormalities are a result of cardiovascular autonomic dysfunction.

Current Therapeutic Modalities for the Management of Chronic Diabetic Wounds of the Foot

Impaired wound healing is common in patients with diabetes mellitus (DM). Different therapeutic modalities including wound debridement and dressing, transcutaneous electrical nerve stimulation (TENS), nanomedicine, shockwave therapy, hyperbaric (HBOT) and topical (TOT) oxygen therapy, and photobiomodulation (PBM) have been used in the management of chronic diabetic foot ulcers (DFUs). The selection of a suitable treatment method for DFUs depends on the hosts' physiological status including the intricacy and wound type. Effective wound care is considered a critical component of chronic diabetic wound management. This review discusses the causes of diabetic wounds and current therapeutic modalities for the management of DFUs, specifically wound debridement and dressing, TENS, nanomedicine, shockwave therapy, HBOT, TOT, and PBM.

Association between heart rate-corrected QT interval and severe peripheral arterial disease in patients with type 2 diabetes and foot ulcers

BACKGROUND

A prolonged heart rate-corrected QT interval (QTc) has been associated with peripheral artery disease (PAD) in the general population. However, no study to date has identified a link between prolonged QTc and the severity of PAD in patients with diabetes mellitus and foot ulcers (DFUs). This study aimed to investigate this relationship.

METHODS

This multicenter study enrolled 281 patients with DFUs. The severity of PAD was classified into no severe PAD group (without stenosis or occlusion) and severe PAD group (with stenosis or occlusion) based on duplex ultrasonography. The association of prolonged QTc with severe PAD was evaluated in a multivariable mixed-effect logistic regression model, with the hospital as a random effect. Directed acyclic graphs were used to drive the selection of variables to fit the regression model.

RESULTS

Patients with severe PAD had longer QTc than those without. Based on the multivariable mixed-effect logistic regression model, a prolonged QTc was positively associated with severe PAD (odds ratio (OR) = 2.61; 95% CI: 1.07-6.35) and severe DFUs (Wagner grade score ≥ 3) (OR = 2.87; 95% CI: 1.42-5.81).

CONCLUSIONS

A prolonged QTc was associated with severe PAD in patients with DFUs. Further research is required to ascertain whether the association is causal.

Effects of adding adjunctive hyperbaric oxygen therapy to standard wound care for diabetic foot ulcers: a protocol for a systematic review with meta-analysis and trial sequential analysis

INTRODUCTION

Diabetic foot ulcer represents a major health problem globally. Preliminary studies have indicated that systemic treatment of diabetic foot ulcer patients with hyperbaric oxygen therapy have beneficial effects on wound healing, risk of amputation, glycaemic control, atherosclerosis, inflammatory markers and other clinical and laboratory parameters. This protocol for a systematic review aims at identifying the beneficial and harmful effects of adding hyperbaric oxygen therapy to standard wound care for diabetic foot ulcers.

METHODS AND ANALYSIS

This protocol was performed following the recommendations of the Cochrane Collaboration and the eight-step assessment procedure suggested by Jakobsen and colleagues. We plan to include all relevant randomised clinical trials assessing the effects of hyperbaric oxygen therapy in the treatment of diabetic foot ulcer versus any control group with any intervention defined as standard wound care or similar, together with sham interventions. Our primary outcome will be: all-cause mortality, serious adverse events and quality of life. Our secondary outcomes will be: healing of index wound, major amputation and wound infection. Any eligible trial will be assessed and classified as either high risk of bias or low risk of bias, and our conclusions will be based on trials with low risk of bias. The analyses of the extracted data will be performed using Review Manager 5 and Trial Sequential Analysis. For both our primary and secondary outcomes, we will create a 'Summary of Findings' table and use GRADE (Grading of Recommendations Assessment, Development and Evaluation) assessment to assess the quality of the evidence.

ETHICS AND DISSEMINATION

We use publicly accessible documents as evidence, there is no participant involvement at an individual level and an institutional ethics approval is not required. The results of the review will be sought published in a peer-reviewed journals, also in the event of insignificant results or null results, and thereby it will be disseminated to clinicians and public available.

PROSPERO REGISTRATION NUMBER

CRD42019139256.

Transcutaneous oxygen pressure as a predictor for short-term survival in patients with type 2 diabetes and foot ulcers: a comparison with ankle-brachial index and toe blood pressure

AIMS

Ankle-brachial index (ABI) is the most commonly used test when diagnosing peripheral vascular disease and is considered a marker for cardiovascular risk. Transcutaneous oxygen pressure (TcPO₂), a test associated with microvascular function, has in several studies shown better correlation with diabetic foot ulcer (DFU) healing. Whether a low TcPO₂ could be a marker for mortality in the high-risk population of DFU patients has not been evaluated before. The aim of this study was to evaluate the predictive value of TcPO₂ in comparison with ABI and toe blood pressure (TBP) on 1-year mortality in type 2 diabetes patients with DFU.

METHODS

Type 2 diabetes patients aged ≤ 90 years, with one DFU who attended our multidisciplinary DFU-unit during year 2013-2015 and were screened with TcPO₂, ABI and TBP were retrospectively evaluated. One-year mortality was assessed from the national death register in Sweden.

RESULTS

A total of 236 patients (30% women) with a median age of 76 (69-82) years were evaluated in this study. Within 1 year, 14.8% of the patients died. TcPO₂ < 25 mmHg was associated with a higher 1-year mortality compared with TcPO₂ ≥ 25 mmHg (27.7 vs. 11.6%, p = 0.003). TBP and ABI did not significantly influence 1-year mortality. In a Cox regression analysis adjusted for confounders, TcPO₂ was independently predicting 1-year mortality with a hazard ratio for TcPO₂ < 25 mmHg of 2.8 (95% CI 1.34-5.91, p = 0.006).

CONCLUSIONS

This study indicates that a low TcPO₂ is an independent prognostic marker for 1-year mortality among patients with type 2 diabetes and DFU.

Association between QTc interval prolongation and outcomes of diabetic foot ulcers: Data from a 4-year follow-up study in China

OBJECTIVES

To examine whether QTc interval prolongation is an independent risk factor of outcomes in patients with diabetic foot ulcers (DFU).

RESEARCH DESIGN AND METHODS

331 patients with type 2 diabetes and DFU hospitalized in a Chinese tertiary hospital were recruited. ECG was done at baseline and QTc interval was calculated through Bazett's formula. Participants were classified into 2 groups according to the QTc interval as prolonged (≥440 ms) or not (<440 ms). These patients were followed-up for an average of 48 months to observe the outcomes, including ulcer healing, ulcer recurrence, nonfatal cerebral or cardiovascular events (NCCVE), cerebral cardiovascular death, cardiac death and all-cause death. The associations between the risk of outcomes and QTc interval prolongation, as well as per 1-SD increase in QTc interval were analyzed by Cox proportional-hazards models.

RESULTS

In terms of the univariate Cox proportional hazard models, patients with QTc interval prolongation had a higher all-cause mortality (HR = 1.621, 95%CI: 1.040-2.526, P = .013), higher cardiac mortality (HR = 2.011 95%CI: 1.106-3.657, P = .019), higher cerebral cardiovascular mortality (HR = 1.525, 95%CI: 0.8151-2.852, P = .045). The multivariate analysis showed that QTc prolongation was an independent risk factor for cardiac death (HR = 5.465, 95%CI: 2.818-8.112, P = .039). Similar results were obtained when QTc interval was used as a continue variable, a 1-SD increase in QTc interval was associated with an 5.883 times risk for cardiac mortality (HR = 6.883, 95%CI: 4.153-9.613, P = .012). The association between QTc interval prolongation with ulcer healing, recurrence and NCCVE were not observed either in univariate or multivariate analysis (P > .05).

CONCLUSION

QTc interval prolongation was a plausible predictor for cardiac death in DFU patients, but it cannot accurately predict ulcer healing or recurrence.

Diabetic foot syndrome in elderly patients

In elderly patients with diabetes mellitus and mild deterioration of the lower extremities, peripheral artery disease and diabetic peripheral neuropathy may contribute to the development of a diabetic foot syndrome. Early diagnosis and intervention can help to preserve the foot and thus significantly increase quality of life with diagnostic and therapeutic procedures being the same in elderly and in young patients.

Non-invasive diagnosis is possible in most bed-ridden patients and should take into account reasonable therapeutic options against the background of overall morbidity, physical performance and quality of life, which should be discussed with the patient and his relatives. Multidisciplinary care structures facilitate treatment and might lead to reduced amputation rates and an improved well-being.

Risk of Mortality Associated With QT and JT Intervals at Different Levels of QRS Duration (from the Third National Health and Nutrition Examination Survey)

QT prolongation in the setting of QRS >120 ms is believed to be triggered by prolonged depolarization rather than repolarization. Hence, JT interval is suggested as an alternative to QT interval when QRS duration is prolonged. It is unclear, however, if JT and QT intervals portend similar risk of mortality for different durations of QRS. We examined the association between QT and JT, separately, with all-cause mortality across different levels of QRS duration in 8,025 participants (60 ± 13 years, 41% white and 54% women) from the Third National Health and Nutrition Examination Survey. At baseline (1986 to 1994), 486 participants (6%) had QRS duration ≥120 ms. During a follow-up of up to 18 years, 3,045 deaths (38%) occurred. There were significant nonlinear relations of QT and JT intervals with mortality (p <0.001). Hence, QT and JT were categorized as prolonged (>95th percentile), shortened (<5th percentile), and normal (reference group). In multivariate-adjusted Cox regression models, prolonged JT (hazard ratio [HR] 4.75, 95% confidence interval [CI] 1.86 to 12.11) was associated with increased risk of mortality more than prolonged QT (HR 1.50, 95% CI 1.03 to 2.17) in participants with QRS ≥120 ms (interaction p = 0.02). In participants with QRS duration <120 ms, prolonged QT and JT were equally predictive of all-cause mortality (HR 1.27, 95% CI 1.06 to 1.54, and HR 1.31, 95% CI 1.10 to 1.55, respectively). Similar patterns were observed with shortened QT and JT intervals. In conclusion, although both QT and JT intervals are predictive of mortality, JT is more predictive in the setting of QRS duration >120 ms supporting the use of JT interval in patients with prolonged QRS.