Comparison of the Renoprotective Effect of Febuxostat for the Treatment of Hyperuricemia between Patients with and without Type 2 Diabetes Mellitus: A Retrospective Observational Study

Chronic kidney disease: Which role for xanthine oxidoreductase activity and products?

The present review explores the role of xanthine oxidoreductase (XOR) in the development and progression of chronic kidney disease (CKD). Human XOR is a multi-level regulated enzyme, which has many physiological functions, but that is also implicated in several pathological processes. The main XOR activities are the purine catabolism, which generates uric acid, and the regulation of cell redox state and cell signaling, through the production of reactive oxygen species. XOR dysregulation may lead to hyperuricemia and oxidative stress, which could have a pathogenic role in the initial phases of CKD, by promoting cell injury, hypertension, chronic inflammation and metabolic derangements. Hypertension is common in CKD patients and many mechanisms inducing it (upregulation of renin-angiotensin-aldosterone system, endothelial dysfunction and atherosclerosis) may be influenced by XOR products. High XOR activity and hyperuricemia are also risk factors for obesity, insulin resistance, type 2 diabetes and metabolic syndrome that are frequent CKD causes. Moreover, CKD is common in patients with gout, which is characterized by hyperuricemia, and in patients with cardiovascular diseases, which are associated with hypertension, endothelial dysfunction and atherosclerosis. Although hyperuricemia is undoubtedly related to CKD, controversial findings have been hitherto reported in patients treated with urate-lowering therapies.

Prospective randomized comparison of effect on coronary endothelial and renal function between febuxostat and benzbromarone in hyperuricemic patients with coronary artery disease: EFEF study

Background and Aims

There are two types of serum uric acid-lowering agents, the xanthine oxidoreductase (XO) inhibitor and non-XO inhibitor. We investigated whether febuxostat, XO inhibitor, could produce more favorable effects on coronary endothelial function (CEF) and renal function than benzbromarone, non-XO inhibitor, in hyperuricemic coronary artery disease (CAD) patients.

Methods

We divided 21 hyperuricemic patients with stenting for left anterior descending (LAD) or left circumflex (LCX) artery into patients started on febuxostat (F group) and those on benzbromarone (B group). After 8 months, all patients underwent CEF evaluations (acetylcholine provocation test) and optical coherence tomography (OCT) for non-culprit vessels (e.g. if patients received LAD stenting, we evaluated LCX). We compared the diameter ratio induced by acetylcholine and baseline (CEF ratio), thin-cap fibroatheroma and calcified plaque by OCT, uric acid, oxidative stress biomarkers, and renal function including estimated glomerular filtration rate (eGFR) between F and B groups. Creatinine 2 days after stenting was measured to evaluate contrast-induced nephropathy (CIN).

Results

Change of eGFR was significantly lower in F group (n= 11) than B group over 8 months while the other parameters including CEF ratio were similar. F group showed favorable effects for CIN.

Conclusion

In conclusion, 8-months of febuxostat, XO inhibitor, does not significantly protect CEF but can protect the renal function including CIN in hyperuricemic patients with CAD compared to benzbromarone, non-XO inhibitor.

Different renoprotective effects of luseogliflozin depend on the renal function at the baseline in patients with type 2 diabetes: A retrospective study during 12 months before and after initiation

Aims

The safety and efficacy, particularly, the factors associated with the renal prognosis, were assessed over 12 months after the initiation of luseogliflozin therapy in Japanese patients with type 2 diabetes and renal impairment.

Methods

In total, 238 patients treated with luseogliflozin (2.5 mg, once daily) were studied as the safety analysis set. Two hundred and two subjects whose medication was continued over 12 months were investigated as the full analysis set. The subjects were divided into 3 groups based on the estimated glomerular filtration rate (eGFR): high eGFR (n = 49), normal eGFR (n = 116) and low eGFR (n = 37) groups.

Results

The body weight, systolic blood pressure, HbA1c and urinary protein excretion gradually decreased from baseline in all eGFR groups. While the eGFR was significantly reduced from baseline in the high and normal eGFR groups, the eGFR did not significantly differ over time in the low eGFR group. There was no marked difference in the frequency of adverse events that were specific for SGLT2 inhibitors among the 3 groups in the safety analysis set.

Conclusions

Luseogliflozin can preserve the renal function in the medium term in patients with type 2 diabetes and renal impairment without an increase in specific adverse events.

Changes in Urinary Microalbumin Levels after Correction of Hyperuricemia in Patients with Gout: An Observational Cohort Study

Background

Gout is commonly associated with metabolic syndrome. Strong association between the serum uric acid level and microalbuminuria has also been observed in various studies.

Aim

To observe the change in urinary microalbumin after urate-lowering treatment in patients with gout and microalbuminuria. Methodology. A prospective, observational study was conducted at a tertiary-level rheumatic center (NCRD) in Kathmandu, Nepal. Adults diagnosed with gout using the 2015 ACR/EULAR criteria and microalbuminuria were enrolled in the study after obtaining informed consent. Sociodemographic profile and clinical history were recorded at baseline. Serum uric acid levels, spot urinary microalbumin (MAU) excretion, blood sugar, lipid profile, and blood pressure were measured at baseline, 3-month follow-up, and 6-month follow-up. A paired t-test was used to compare the change in mean MAU after treatment.

Results

A total of 778 patients diagnosed with gout were screened for microalbuminuria. Among them, 114 (14.6%) had urinary microalbumin levels of >30.0 mg/L during presentation. Mean MAU level among those with microalbuminuria was 132.4 ± 124.6 mg/L. Thirty-five patients had concomitant HTN and were put on ARBs (20 mg of telmisartan). All received 40 mg of febuxostat. In patients with ARBs, MAU reduced significantly after 3 months of treatment with ARBs. Reduction in MAU in those without ARBs was seen after the 6-month follow-up, and the change was statistically significant.

Conclusions

There is significant reduction in MAU after the use of urate-lowering drugs in patients with gout.

Febuxostat is superior to allopurinol in delaying the progression of renal impairment in patients with chronic kidney disease and hyperuricemia

PURPOSE

This study aimed to compare efficacy of renal-protective function between febuxostat and allopurinol in patients with chronic kidney disease (CKD) and hyperuricemia (HUA).

METHODS

Totally 152 CKD stage 2-3 patients complicated with HUA were recruited. According to their uric acid-lowering therapy, there were 67 patients included in febuxostat group and 85 in allopurinol group, respectively. Estimated glomerular filtration rate (eGFR), serum creatinine (Scr), 24-h proteinuria, serum uric acid (SUA) were measured at M0, M1, M3 and M6 after the treatment. Primary outcome was proportion of patients showing ≥ 10% decline in eGFR from baseline at M6.

RESULTS

The eGFR at M6 was numerically higher at M6 and eGFR change (M6-M0) was increased in febuxostat group compared with allopurinol group. Most importantly, the proportion of patients showing a ≥ 10% decline in eGFR from baseline at M6 was reduced in febuxostat group compared with allopurinol group. Multivariate logistic regression analyses further validated that febuxostat vs. allopurinol was an independent predictor for reduced risk of eGFR decline ≥ 10% from baseline. Besides, SUA change (M6-M0) was decreased, but Scr change (M6-M0) and 24-h proteinuria change (M6-M0) were similar in febuxostat group compared with allopurinol group.

CONCLUSIONS

Febuxostat presents a superior effect in delaying renal impairment progression compared with allopurinol in CKD patients complicated with HUA.

Physiology of Hyperuricemia and Urate-Lowering Treatments

Gout is the most common form of inflammatory arthritis and is a multifactorial disease typically characterized by hyperuricemia and monosodium urate crystal deposition predominantly in, but not limited to, the joints and the urinary tract. The prevalence of gout and hyperuricemia has increased in developed countries over the past two decades and research into the area has become progressively more active. We review the current field of knowledge with emphasis on active areas of hyperuricemia research including the underlying physiology, genetics and epidemiology, with a focus on studies which suggest association of hyperuricemia with common comorbidities including cardiovascular disease, renal insufficiency, metabolic syndrome and diabetes. Finally, we discuss current therapies and emerging drug discovery efforts aimed at delivering an optimized clinical treatment strategy.

Side Effects and Interactions of the Xanthine Oxidase Inhibitor Febuxostat

The paper addresses the safety of febuxostat and summarizes reports on side effects and interactions of febuxostat published by the cut-off date (last day of literature search) of 20 March 2018. Publications on side effects and the interactions of febuxostat were considered. Information concerning the occurrence of side effects and interactions in association with the treatment with febuxostat was collected and summarized in the review. The incidence of severe side effects was much less frequent than mild side effects (1.2–3.8% to 20.1–38.7%). The rate and range of febuxostat side effects are low at doses of up to 120 mg and only increase with a daily dose of over 120 mg. The publications reveal no age-dependent increase in side effects for febuxostat. In patients with impaired renal function, no increase in adverse events is described with a dose of up to 120 mg of febuxostat per day. Patients with impaired liver function had no elevated risk for severe side effects. A known allopurinol intolerance increases the risk of skin reactions during treatment with febuxostat by a factor of 3.6. No correlation between treatment with febuxostat and agranulocytosis has been confirmed. Possible interactions with very few medications (principally azathioprine) are known for febuxostat. Febuxostat is well tolerated and a modern and safe alternative to allopurinol therapy.

Urate-Lowering Therapy Ameliorates Kidney Function in Type 2 Diabetes Patients With Hyperuricemia

Background

Hyperuricemia often causes kidney dysfunction which increases serum urate, forming a vicious cycle in the kidney. In this study, urate-lowering therapy was demonstrated in type 2 diabetic patients with hyperuricemia to evaluate the effect on diabetic nephropathy.

Methods

Type 2 diabetic patients with hyperuricemia (n = 34) were treated by urate-lowering drugs. Serum urate levels, estimated glomerular filtration rate (eGFR), blood pressure, HbA1c, and urinary albumin-to-creatinine ratio (UACR) were measured for 52 weeks. The parameters at the endpoint when serum urate decreased to below 6.0 mg/dL and at 52 weeks were compared to the initial levels at week 0.

Results

Serum urate level decreased to the endpoint in all patients and was maintained at under 6.0 mg/dL throughout the observation period. eGFR significantly increased at the endpoint and also at 52 weeks. Overall UACR did not change after 52 weeks; however, the treatment decreased UACR significantly in patients with no microalbuminuria. There was a negative relationship between the change of serum urate levels and the change of eGFR, and a negative relationship between the baseline UACR and the change of UACR when patients with macroalbuminuria were excluded. There were no changes in HbA1c levels and blood pressure before and after the treatment.

Conclusions

There were significant improvements in kidney function by lowering serum urate levels to under 6.0 mg/dL and the effect was maintained for at least 52 weeks. This treatment may be one strategy to slow the progression of nephropathy in type 2 diabetic patients with hyperuricemia.