Effects of allopurinol on renal function in patients with diabetes: a systematic review and meta-analysis

Febuxostat provides renoprotection in patients with hyperuricemia or gout: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

It is unknown whether febuxostat can delay the progression of kidney dysfunction and reduce kidney endpoint events. The aim was to evaluate the renoprotective effect of febuxostat in patients with hyperuricemia or gout by performing a meta-analysis of randomized controlled trials (RCTs).

METHODS

MEDLINE, Web of science, EMBASE, ClinicalTrials.gov, and the Cochrane Central Register for Randomized Controlled Trials were searched. The main outcomes included kidney events (serum creatinine doubling or progression to end-stage kidney disease or dialysis). The secondary outcomes were the rate of change in the estimated glomerular filtration rate (eGFR) and changes in the urine protein or urine albumin to creatinine ratio from baseline to the end of follow-up. We used random-effects models to calculate the pooled risk estimates and 95% CIs.

RESULTS

A total of 16 RCTs were included in the meta-analysis. In comparison with the control group, the patients who received febuxostat showed a reduced risk of kidney events (RR = 0.56, 95% CI 0.37-0.84, p = 0.006) and a slower decline in eGFR (WMD = 0.90 mL/min/1.73 m2, 95% CI 0.31-1.48, p = 0.003). The pooled results also revealed that febuxostat use reduced the urine albumin to creatinine ratio (SMD = -0.21, 95% CI -0.41 to -0.01, p = 0.042).

CONCLUSION

Febuxostat use is associated with a reduced risk of kidney events and a slow decline in eGFR. In addition, the urine albumin to creatinine ratio decreased in febuxostat users. Accordingly, it is an effective drug for delaying the progression of kidney function deterioration in patients with gout.Systematic review registration: PROSPERO CRD42021272591.

Efficacy and Safety of Allopurinol on Chronic Kidney Disease Progression: A Systematic Review and Meta-Analysis

OBJECTIVE

Hyperuricemia is associated with the progression of chronic kidney disease (CKD). Whether urate-lowering treatment with allopurinol can delay disease progression remains controversial.

METHODS

Relevant databases were searched. Randomized clinical trials comparing the efficacy and -safety of allopurinol in patients with CKD were selected. The primary outcomes were changes in serum uric acid concentration and estimated glomerular filtration rate (eGFR). Random-effects modeling was used to -calculate the standard mean difference (SMD) with 95% CIs.

RESULTS

Four trials enrolling 698 participants were included. All were 2-arm parallel trials with a mean duration follow-up of 22.5 months. Congenital anomalies of the kidney and urinary tract were the most common cause of CKD in children, whereas diabetes was the leading cause of CKD in adults. Allopurinol significantly increased the eGFR compared with control groups (SMD, 2.04; 95% CI, 0.60-3.49; p = 0.005; I2 = 98.23%). Allopurinol led to a significant decrease in serum uric acid concentration compared with the control group (SMD, -5.16; 95% CI, -8.31 to -2.01; p = 0.001; I2 = 98.80%). No significant difference in adverse effects was identified between treatment and control groups.

CONCLUSIONS

Allopurinol treatment in patients with CKD and hyperuricemia slows the decline in eGFR as compared with placebo, without risk of increased adverse effects.

Emerging Roles of Xanthine Oxidoreductase in Chronic Kidney Disease

Xanthine Oxidoreductase (XOR) is a ubiquitous, essential enzyme responsible for the terminal steps of purine catabolism, ultimately producing uric acid that is eliminated by the kidneys. XOR is also a physiological source of superoxide ion, hydrogen peroxide, and nitric oxide, which can function as second messengers in the activation of various physiological pathways, as well as contribute to the development and the progression of chronic conditions including kidney diseases, which are increasing in prevalence worldwide. XOR activity can promote oxidative distress, endothelial dysfunction, and inflammation through the biological effects of reactive oxygen species; nitric oxide and uric acid are the major products of XOR activity. However, the complex relationship of these reactions in disease settings has long been debated, and the environmental influences and genetics remain largely unknown. In this review, we give an overview of the biochemistry, biology, environmental, and current clinical impact of XOR in the kidney. Finally, we highlight recent genetic studies linking XOR and risk for kidney disease, igniting enthusiasm for future biomarker development and novel therapeutic approaches targeting XOR.

Potential of Leave and Fruit Ethanolic Extract of Etlingera hemisphaerica as Antihyperuricemic in Mice (Mus musculus)

<b>Background and Objective:</b> Hyperuricemia is a disease triggered by disorders of uric acid metabolism. Therefore, this study evaluated the potential of leaves ethanolic extract of <i>Etlingera hemisphaerica</i> (LE3H) and fruits ethanolic extract <i>E. hemisphaerica</i> (FE3H) to restore hyperuricemia in mice. <b>Materials and Methods:</b> Six groups (A0, A1, A2, A3, A4 and A5) each consisted of four male mice. Hyperuricemia in mice was induced by giving 0.3 mL of fresh chicken liver juice (FCLJ) for seven days (A1, A2, A3, A4 and A5). The condition of hyperuricemia in A1 is not neutralized. Meanwhile, hyperuricemia conditions in A2, A3, A4 and A5 were neutralized for seven days by giving 0.01 mg g<sup></sup><sup>1</sup> body weight (BW) allopurinol, 0.13, 0.26 and 0.36 mg g<sup></sup><sup>1</sup> BW LE3H. The control group (A0) only received double-distilled water in the same way. Blood uric acid levels were measured with the GCU Meter Device before and after the induction of hyperuricemia and after efforts to neutralize the hyperuricemia condition. Six groups (B0, B1, B2, B3, B4, B5) each consisting of four male mice were also provided to test the potential of FE3H. The recovery potential FE3H against hyperuricemia was tested separately in the same way as was done for LE3H. <b>Results:</b> Giving FCLJ significantly increased (140.00-187.00%) uric acid compared to the control, so hyperuricemia was achieved. Doses of 0.13, 0.26 and 0.36 mg g<sup></sup><sup>1</sup> BW LE3H significantly recovered hyperuricemia as much as 54.09, 56.14 and 60.88%, respectively. Meanwhile, doses of 0.13, 0.26 and 0.36 mg g<sup></sup><sup>1</sup> FE3H significantly recovered hyperuricemia as much as 60.37, 62.24 and 65.572%, respectively. The LE3H and FE3H at the same dose showed that FE3H had a higher potential to restore hyperuricemia than LE3H. <b>Conclusion:</b> Leave and fruit ethanolic extract of <i>E. hemisphaerica</i> can potentially restore hyperuricemia in mice.

Uric Acid and Chronic Kidney Disease: Still More to Do

Gout and hyperuricemia are present in 25% and 60% of patients with chronic kidney disease (CKD), respectively. Despite the common association, the role of uric acid in the progression of kidney disease and in metabolic complications remains contested. Some authorities argue that the treatment of asymptomatic hyperuricemia in CKD is not indicated, and some have even suggested hyperuricemia may be beneficial. Here, we review the various arguments both for and against treatment. The weight of the evidence suggests asymptomatic hyperuricemia is likely injurious, but it may primarily relate to subgroups, those who have systemic crystal deposits, those with frequent urinary crystalluria or kidney stones, and those with high intracellular uric acid levels. We recommend carefully designed clinical trials to test if lowering uric acid in hyperuricemic subjects with cardiometabolic complications is protective.

Association of Visceral Fat Area and Hyperuricemia in Non-Obese US Adults: A Cross-Sectional Study

This study aimed to investigate the relationship between visceral fat area (VFA) and hyperuricemia (HUA) among non-obese adults. We extracted data from 6224 US adults aged 20−59 years from the National Health and Nutrition Examination Survey (NHANES) from 2011−2018. The VFA was divided into four quartiles (Q1−Q4). We used multivariable logistic regression models to control for known confounders. A generalized additive model (GAM) and restricted cubic spines were used to examine the association between VFA and HUA stratified by sex, and a two-piecewise linear regression model was used to calculate the threshold effect among males. The results revealed that the prevalence of HUA was 11.8% (men 15.8%, women 7.2%). In the fully adjusted model, there was a positive association between VFA and HUA [as a quartile variable, Q4 vs. Q1, odds ratio (OR): 3.77 and 95% confidence interval (CI): (2.47~5.75), p < 0.001, p for trend < 0.001; as a continuous variable, per 10 cm2 increment, OR (95%CI):1.10(1.07,1.14), p < 0.001]. Besides, this positive association remained significantly stratified by sex. Interestingly, we observed a nonlinear dose-response relationship between VFA and HUA in males (inflection point: 107.46 cm2). In conclusion, our study confirmed a significant positive relationship between VFA and HUA among non-obese adults and remained statistically significant when stratified by sex.