Elevated serum uric acid levels are independent risk factors for diabetic foot ulcer in female Chinese patients with type 2 diabetes

Hyperuricemia - consequences of not initiating therapy. Benefits and drawbacks of treatment

Hyperuricemia, characterized by elevated levels of uric acid in the body, is associated with several health risks, including gout, urolithiasis and cardiovascular disease. Although treatment options are available, they can lead to hypersensitivity reactions, particularly with allopurinol therapy. This paper provides a comprehensive review of the consequences of hyperuricemia, the need for treatment and the potential adverse effects of allopurinol, illustrated by a case study. The study highlights the importance of careful consideration before initiating therapy, particularly in patients with comorbidities and concomitant medication. It emphasizes the need for vigilant monitoring and individualized treatment approaches to reduce adverse effects. In addition, genetic factors, particularly HLA-B*5801, play an important role in determining susceptibility to allopurinol hypersensitivity reactions. This paper highlights the importance of informed decision making in the management of hyperuricemia to optimize patient outcomes while minimizing the risks associated with treatment.

The Ratio of Serum Uric Acid to Glycosylated Haemoglobin as a Predictor of All-Mortality in Elderly Patients with Diabetic Foot Ulcers: A Longitudinal Cohort Study

Aim

To clarify the relationship between serum uric acid (UA) and glycosylated hemoglobin (UA/HbA1c) ratio and all-cause mortality in patients with diabetic foot ulcers (DFUs).

Methods

A total of 172 inpatients with DFUs (PEDIS grades 2-4) were eligible for inclusion in this study from 2018 to 2023. This was a retrospective, longitudinal cohort study. All subjects were followed up every 6 months for a median of 60 months. According to the cutoff value of the UA/HbA1c ratio of 39.07 obtained from ROC analysis, the participants were divided into two groups: low-level (≤ 39.07, n = 107) and high-level (> 39.07, n = 65) groups. The correlation between UA/HbA1c ratio and all-cause mortality was also evaluated by Cox regression analysis TheKaplan-Meier survival curve analysis and Log rank tests were used to assess the incidence rates of all-cause mortality. The contribution rate of risk factors was estimated by the population-attributable risk percentage (PAR%) analysis.

Results

ROC analysis showed that the optimal cutoff values for UA and the UA/HbA1c ratio were 372 μmol/L and 39.07, respectively. Multivariate Cox regression analysis indicated that a high UA/HbA1c ratio (HR =4.63; 95% CI = 2.004-10.7, P < 0.001) was independently associated with a high risk of all-cause mortality in patients with DFUs. Stratified analysis indicated that subjects aged ≥ 60 years had a greater risk of all-cause mortality associated with a high UA/HbA1c ratio (HR = 4.450; 95% CI = 1.711-11.574, P = 0.002). Kaplan-Meier survival analysis showed that all-cause mortality had a significant positive association with a high UA/HbA1c ratio (log-rank, P < 0.001) and a significant negative correlation with the lowered HbA1c level (< 6.5%) after a follow-up of 32 months (log-rank, P < 0.001). The population attributable risk percentage (PAR%) analysis suggested that the contribution rate of the high-level UA/HbA1c ratio to all-cause mortality was 33.7%, which was much greater than the 19.69% of UA.

Conclusion

In brief, our study showed that for every 1.0% increase in the UA/HbA1c ratio, the all-cause mortality rate in elderly patients with DFUs aged ≥ 60 years increased by 3.45-fold. For elderly patients with DFUs, a safe and effective strategy to reduce all-cause mortality is to strictly control serum UA levels to < 372 μmol/L and appropriately loosen the control goal of HbA1c to ≥ 6.5%.

Keeping an eye on the diabetic foot: The connection between diabetic eye disease and wound healing in the lower extremity

Diabetic eye disease is strongly associated with the development of diabetic foot ulcers (DFUs). DFUs are a common and significant complication of diabetes mellitus (DM) that arise from a combination of micro- and macrovascular compromise. Hyperglycemia and associated metabolic dysfunction in DM lead to impaired wound healing, immune dysregulation, peripheral vascular disease, and diabetic neuropathy that predisposes the lower extremities to repetitive injury and progressive tissue damage that may ultimately necessitate amputation. Diabetic retinopathy (DR) is caused by cumulative damage to the retinal mic-rovasculature from hyperglycemia and other diabetes-associated factors. The severity of DR is closely associated with the development of DFUs and the need for lower extremity revascularization procedures and/or amputation. Like the lower extremity, the eye may also suffer end-organ damage from macrovascular compromise in the form of cranial neuropathies that impair its motility, cause optic neuropathy, or result in partial or complete blindness. Additionally, poor perfusion of the eye can cause ischemic retinopathy leading to the development of proliferative diabetic retinopathy or neovascular glaucoma, both serious, vision-threatening conditions. Finally, diabetic corneal ulcers and DFUs share many aspects of impaired wound healing resulting from neurovascular, sensory, and immunologic compromise. Notably, alterations in serum biomarkers, such as hemoglobin A1c, ceruloplasmin, creatinine, low-density lipoprotein, and high-density lipoprotein, are associated with both DR and DFUs. Monitoring these parameters can aid in prognosticating long-term outcomes and shed light on shared pathogenic mechanisms that lead to end-organ damage. The frequent co-occurrence of diabetic eye and foot problems mandate that patients affected by either condition undergo reciprocal comprehensive eye and foot evaluations in addition to optimizing diabetes management.

miRNA-770-5p expression is upregulated in patients with type 2 diabetes and miRNA-770-5p knockdown protects pancreatic β-cell function via targeting BAG5 expression

MicroRNA (miR)-770-5p expression is increased in patients with type 2 diabetes mellitus (T2DM) compared with healthy controls; however, the roles and molecular mechanism underlying miR-770-5p in T2DM are not completely understood. In the present study, the reverse transcription-quantitative PCR (RT-qPCR) results indicated that miR-770-5p expression was significantly increased and Bcl-2 associated athanogene 5 (BAG5) expression was significantly decreased in the serum of patients with T2DM compared with healthy volunteers. TargetScan and a dual luciferase reporter gene system were used to predict and verify BAG5 as a target gene of miR-770-5p. Additionally, the RT-qPCR results demonstrated that miR-770-5p expression was significantly increased and BAG5 expression was significantly decreased in uric acid (UA)-treated Min6 cells compared with control cells. Min6 cells were transfected with miR-770-5p inhibitor and BAG5-small interfering (si)RNA to alter expression levels. The results indicated that miR-770-5p negatively regulated BAG5. The effect of miR-770-5p knockdown on UA-induced pancreatic β-cell damage and dysfunction was subsequently assessed. Min6 cells were transfected with miR-770-5p inhibitor or miR-770-5p inhibitor + BAG5-siRNA for 48 h, followed by treatment with or without 5 mg/dl UA for 24 h. Cell viability, apoptosis, apoptosis-related factor expression levels and insulin secretion were assessed. The results demonstrated that UA treatment significantly reduced cell viability, increased cell apoptosis and reduced insulin secretion in Min6 cells compared with the control group. miR-770-5p inhibitor significantly attenuated UA-induced injury and dysfunction of Min6 cells, whereas BAG5 knockdown abolished the protective effects of miR-770-5p inhibitor on UA-damaged Min6 cells. In conclusion, miR-770-5p was highly expressed in the serum of patients with T2DM compared with healthy volunteers. In UA-treated pancreatic β-cells, compared with the inhibitor control group, miR-770-5p knockdown regulated the expression of apoptosis-related genes, increased cell viability, inhibited cell apoptosis and increased insulin secretion by targeting BAG5. Therefore, the present study suggested that miR-770-5p inhibitor may serve a protective role in T2DM.

Asymptomatic hyperuricemia: is it really asymptomatic?

PURPOSE OF REVIEW

Hyperuricemia is highly prevalent, affecting approximately 38 million individuals in the United States. However, the significance of asymptomatic hyperuricemia - hyperuricemia in the absence of gout - continues to be debated.

RECENT FINDINGS

Asymptomatic hyperuricemia results in monosodium urate crystal deposition in tissues, which may promote chronic inflammation. Intracellularly, hyperuricemia inhibits the master regulator adenosine monophosphate (AMP)-associated protein kinase and may condition innate immune responses through durable epigenetic modifications. At the population level, asymptomatic hyperuricemia is associated with multiple comorbidities, including hypertension, chronic kidney disease, coronary artery disease, and diabetes; limitations of these studies include that most are retrospective and some do not rigorously distinguish between asymptomatic hyperuricemia and gout. Treatment studies suggest that urate lowering may reduce the risk of incidence or progression of some of these comorbidities; unfortunately, many of these treatment studies are small or flawed, and not all study results are consistent.

SUMMARY

Accumulating evidence suggests that asymptomatic hyperuricemia contributes to the comorbidities with which it associates and that proper asymptomatic hyperuricemia treatment may reduce future risk. Additional prospective trials are needed to definitely establish causality and support decision-making as to whether, and which patients with asymptomatic hyperuricemia would warrant urate-lowering treatment.

Risk factors for diabetic foot complications in type 2 diabetes-A systematic review

Aims

With increasing numbers of patients with type 2 diabetes mellitus (T2DM) worldwide, the number of associated diabetic foot complications might also increase. This systematic review was performed to summarize published data about risk factors for the diabetic foot (DF) syndrome in order to improve the identification of high-risk patients.

Materials and methods

Six electronic databases were searched for publications up to August 2019 using predefined stringent inclusion and exclusion criteria.

Results

Of 9,476 identified articles, 31 articles from 28 different study populations fulfilled the criteria for our evaluation. The overall quality of the studies was good, and the risk of bias was low. There was large heterogeneity among the studies concerning study protocols and patient populations analysed. A total of 79 risk factors were analysed within this review. The majority of studies described a consistently positive association with different outcomes of interest related to DF for gender, peripheral neuropathy, retinopathy, nephropathy, poor glycaemic control, insulin use, duration of diabetes, smoking and height. For age, hypertension, dyslipidaemia and body mass index, the results remain inconsistent.

Conclusion

A most up-to-date literature review resulted in glycaemic control and smoking as the only amenable risk factors with a consistently positive association for DF. Due to the high personal and financial burden associated with DF and the large heterogeneity among included studies, additional longitudinal studies in large patient populations are necessary to identify more modifiable risk factors that can be used in the prediction and prevention of DF complications.

Higher Serum Uric Acid Level Predicts Non-alcoholic Fatty Liver Disease: A 4-Year Prospective Cohort Study

Background: Non-alcoholic fatty liver disease (NAFLD) has become a serious disease affecting people's health in the world. This article studies the causal relationship between NAFLD and serum uric acid (SUA) levels. Methods: During the 4 years of follow-up in a fixed cohort that was established in 2014, 2,832 follow-up subjects without NAFLD were finally included in this study. The study population was divided into four groups according to baseline SUA levels. Cox hazard regression model and Kaplan-Meier survival curves analysis were used to predict risk factors of NAFLD. The receiver operating characteristic curve analyses were used to determine SUA cutoffs for predicting NAFLD. Results: The cumulative prevalence rates of NAFLD were 33.97% (962/2,832), 38.93% (758/1,947) in males and 23.05% (204/885) in females. The results showed that males had a higher incidence of NAFLD (χ² = 68.412, P = 0.000). The Cox regression analysis disclosed that the hazard ratios of NAFLD [95% confidence interval (CI)] were 1.431 (95% CI, 1.123~1.823), 1.610 (95% CI, 1.262-2.054), and 1.666 (95% CI, 1.287-2.157) across the second to the fourth quartile of SUA adjusted for other confounders. The SUA cutoffs, sensitivity, specificity, and area under the curve (AUC) (95% CI) were ≥288.5 μmol/L, 75.5, 46.5%, 0.637(0.616-0.658), respectively, for total; ≥319.5 μmol/L, 65.8%, 48.4%, 0.590 (0.564-0.615), respectively, for males; and ≥287.5 μmol/L, 51.0%, 75.6%, 0.662 (0.619-0.704), respectively, for females. Kaplan-Meier survival curves revealed that individuals with higher SUA level had an increased risk of NAFLD in comparison to lower SUA level (P = 0.000). Conclusion: Serum uric acid is positively correlated with NAFLD, and elevated SUA level can be used as an independent predictor for NAFLD.

Effects of Uric Acid on Diabetes Mellitus and Its Chronic Complications

With the deepening of the researches on uric acid, especially in the study of metabolic diseases, uric acid has been found to be closely related to obesity, metabolic syndrome, nonalcoholic fatty liver disease, diabetes, and other metabolic diseases. Uric acid causes a series of pathophysiological changes through inflammation, oxidative stress, vascular endothelial injury, and so on and thus subsequently promotes the occurrence and development of diseases. This review confirmed the positive correlation between uric acid and diabetes mellitus and its chronic complications through the pathogenesis and clinical studies aspects.

Global epidemiology of diabetic foot ulceration: a systematic review and meta-analysis †

Diabetic foot is a severe public health issue, yet rare studies investigated its global epidemiology. Here we performed a systematic review and meta-analysis through searching PubMed, EMBASE, ISI Web of science, and Cochrane database. We found that that global diabetic foot ulcer prevalence was 6.3% (95%CI: 5.4-7.3%), which was higher in males (4.5%, 95%CI: 3.7-5.2%) than in females (3.5%, 95%CI: 2.8-4.2%), and higher in type 2 diabetic patients (6.4%, 95%CI: 4.6-8.1%) than in type 1 diabetics (5.5%, 95%CI: 3.2-7.7%). North America had the highest prevalence (13.0%, 95%CI: 10.0-15.9%), Oceania had the lowest (3.0%, 95% CI: 0.9-5.0%), and the prevalence in Asia, Europe, and Africa were 5.5% (95%CI: 4.6-6.4%), 5.1% (95%CI: 4.1-6.0%), and 7.2% (95%CI: 5.1-9.3%), respectively. Australia has the lowest (1.5%, 95%CI: 0.7-2.4%) and Belgium has the highest prevalence (16.6%, 95%CI: 10.7-22.4%), followed by Canada (14.8%, 95%CI: 9.4-20.1%) and USA (13.0%, 95%CI: 8.3-17.7%). The patients with diabetic foot ulcer were older, had a lower body mass index, longer diabetic duration, and had more hypertension, diabetic retinopathy, and smoking history than patients without diabetic foot ulceration. Our results provide suggestions for policy makers in deciding preventing strategy of diabetic foot ulceration in the future. Key messages Global prevalence of diabetic foot is 6.3% (95%CI: 5.4-7.3%), and the prevalence in North America, Asia, Europe, Africa and Oceania was 13.0% (95%CI: 10.0-15.9%), 5.5% (95%CI: 4.6-6.4%), 5.1% (95%CI: 4.1-6.0%), 7.2% (95%CI: 5.1-9.3%), and 3.0% (95% CI: 0.9-5.0%). Diabetic foot was more prevalent in males than in females, and more prevalent in type 2 diabetic foot patients than in type 1 diabetic foot patients. The patients with diabetic foot were older, had a lower body mass index, longer diabetic duration, and had more hypertension, diabetic retinopathy, and smoking history than patients without diabetic foot.

Associations between Serum Uric Acid and the Remission of Non-Alcoholic Fatty Liver Disease in Chinese Males

Epidemiological studies suggest that higher serum uric acid (sUA) level is significantly associated with nonalcoholic fatty liver disease (NAFLD) development. However, little information is available on the relationships between sUA and NAFLD remission. In the present study, 841 NAFLD males (30-75 years) were recruited from a Chinese prospective cohort study (PMMJS) and followed up for five years. The baseline sUA levels of participants were categorized into four quartiles: 191 μmol/L≤ sUA ≤ 347 μmol/L, 347 μmol/L < sUA ≤ 392 μmol/L, 392 μmol/L < sUA ≤ 441 μmol/L and 441 μmol/L<SUA≤676 μmol/L. As the results show, participants with elevated sUA levels at baseline were significantly associated with the decreased rate of NAFLD remission at the end of study (p<0.0001). After adjustment, RR (95%CI) for remitted NAFLD comparing Q1 to Q3 vs Q4 of sUA were 2.95 (1.49-5.83), 2.40 (1.22-4.73) and 1.39 (0.67-2.86), respectively. Furthermore, the sensitivity analysis showed these significant associations were not affected even after exclusion of participants who had hypertension, diabetes mellitus, MetS and hyperlipidemia. Additionally, the presence of the lowest quartile of sUA levels was still significantly associated with remitted NAFLD when the study population was stratified according to the smoking, and the median values of age, ALT, AST, serum creatinine, HDL-C and LDL-C. Therefore, our present study extended the previous findings and suggested that modulation of sUA levels may attenuate the progression of NAFLD.

Linking uric acid metabolism to diabetic complications

Hyperuricemia have been thought to be caused by the ingestion of large amounts of purines, and prevention or treatment of hyperuricemia has intended to prevent gout. Xanthine dehydrogenase/xanthine oxidase (XDH/XO) is rate-limiting enzyme of uric acid generation, and allopurinol was developed as a uric acid (UA) generation inhibitor in the 1950s and has been routinely used for gout prevention since then. Serum UA levels are an important risk factor of disease progression for various diseases, including those related to lifestyle. Recently, other UA generation inhibitors such as febuxostat and topiroxostat were launched. The emergence of these novel medications has promoted new research in the field. Lifestyle-related diseases, such as metabolic syndrome or type 2 diabetes mellitus, often have a common pathological foundation. As such, hyperuricemia is often present among these patients. Many in vitro and animal studies have implicated inflammation and oxidative stress in UA metabolism and vascular injury because XDH/XO act as one of the major source of reactive oxygen species Many studies on UA levels and associated diseases implicate involvement of UA generation in disease onset and/or progression. Interventional studies for UA generation, not UA excretion revealed XDH/XO can be the therapeutic target for vascular injury and renal dysfunction. In this review, the relationship between UA metabolism and diabetic complications is highlighted.