Atrial Fibrillation Risk and Urate-Lowering Therapy in Patients with Gout: A Cohort Study Using a Clinical Database

Individuals of Asian descent are at higher risk for developing hyperuricemia and gout as compared to Western populations. Urate-lowering therapy (ULT) is an effective treatment for hyperuricemia and gout. It was reported that febuxostat, one of the ULTs, raises the risk of atrial fibrillation (AF) in elderly populations. Nevertheless, this association has not been properly investigated in Asian populations. We aimed to investigate the development of AF after ULT with different drugs in an Asian population. We conducted a retrospective cohort study using the clinical database at Kaohsiung Veterans General Hospital. Patients newly diagnosed with gout between 1 January 2013 and 31 December 2020 and with a documented baseline serum uric acid (sUA) level but no prior diagnosis of AF were identified. Patients were divided into three groups-allopurinol, benzbromarone, and febuxostat users. During the follow-up period, the risks of incident AF following the initiation of ULT with different drugs were assessed. Development of incident AF was noted in 43 (6%) of the 713 eligible patients during the follow-up period (mean, 49.4 ± 26.6 months). Febuxostat-treated patients had a higher prevalence of certain comorbidities (diabetes mellitus, heart failure, and chronic kidney disease) and higher CHA2DS2-VASc scores. Compared with allopurinol, neither febuxostat nor benzbromarone was associated with increased adjusted hazard ratios (HR) for incident AF (HR: 1.20, 95% confidence interval [CI]: 0.43-3.34; HR: 0.68, 95% CI: 0.22-2.08). There was no difference in the risk of incident AF among Asian patients with gout who received febuxostat, allopurinol, or benzbromarone. Further studies are needed to evaluate long-term cardiovascular outcomes in patients receiving different ULT drugs.

Low-dose febuxostat exhibits a superior renal-protective effect and non-inferior safety profile compared to allopurinol in chronic kidney disease patients complicated with hyperuricemia: A double-centre, randomized, controlled study

WHAT IS KNOWN AND OBJECTIVE

The present study compared the efficacy and safety of low-dose febuxostat versus allopurinol in chronic kidney disease (CKD) patients complicated with hyperuricemia (HUA).

METHODS

In this double-centre, randomized, controlled study, 120 CKD patients complicated with HUA were recruited and randomly assigned to low-dose febuxostat group (20 mg/day) or allopurinol group (200 mg/day) at 1:1 ratio. The serum creatinine (Scr), serum uric acid (SUA), and estimated glomerular filtration rate (eGFR) were measured at baseline (M0), month (M) 1, M3, and M6. Besides, the drug-related adverse events (AEs) were recorded. The primary outcome was the proportion of patients showing a > 10% decline in eGFR from M0 to M6.

RESULTS

The eGFR level was increased at M6, but similar at M0, M1 and M3 in febuxostat group compared with allopurinol group. Notably, the proportion of patients with >10% decline in eGFR from M0 to M6 was decreased in febuxostat group compared with allopurinol group. However, there was no difference of Scr, SUA at M0, M1, M3 and M6 between febuxostat group and allopurinol group. Moreover, there was no difference of drug-related AEs between febuxostat group and allopurinol group. Further subgroup analysis exhibited that low-dose febuxostat presented superior effect on attenuating eGFR decline and lowering SUA level compared with allopurinol in CKD stage 3 subgroup, but not in CKD stage 2 subgroup.

CONCLUSION

Low-dose febuxostat may exhibit a superior renal-protective effect, non-inferior SUA lowering ability and safety profile compared with allopurinol in CKD patients complicated with HUA.

Long-Term Follow-up of a Randomized Controlled Trial of Allopurinol Dose Escalation to Achieve Target Serum Urate in People With Gout

OBJECTIVE

To determine the long-term use of and adherence to urate-lowering therapy (ULT), serum urate (SU) control, and self-reported flares in participants from a randomized controlled trial of allopurinol dose escalation, in order to achieve target SU concentration (< 0.36 mmol/L) in people with gout.

METHODS

For surviving study participants, ULT dispensing and SU testing within the preceding 12 months was obtained by medical record review. A phone interview was conducted to determine self-reported flares and adherence.

RESULTS

Over a mean follow-up of 6.5 (SD 2.5) years since enrollment, 60 out of 183 (33%) participants had died. Review of the 119 surviving participants showed that 98 (82%) were receiving allopurinol, 5 (4%) were receiving febuxostat, and 10 (8%) were not receiving ULT; for the remaining 6 (5.0%), ULT use could not be determined. In those receiving allopurinol, the mean dose was 28.1 (range -600 to 500) mg/day lower than at the last study visit; 49% were receiving the same dose, 18% were on a higher dose, and 33% were on a lower dose than at the last study visit. SU values were available for 86 of the 119 (72%) participants; 50 out of 86 (58%) participants had an SU concentration of < 0.36 mmol/L. Of the 89 participants who participated in the phone interview, 19 (21%) reported a gout flare in the preceding 12 months and 79 (89%) were receiving allopurinol; 71 (90%) of those receiving allopurinol reported 90% or greater adherence.

CONCLUSION

Most of the surviving participants in the allopurinol dose escalation study had good real-world persistence with allopurinol, remained at target SU, and had a low number of self-reported flares.

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

BACKGROUND/OBJECTIVE

Diabetes mellitus is a common "non-gout" disease with high incidence. Several studies have shown that serum uric acid level in patients with diabetes is higher than that in healthy individuals, and is accompanied by severe albuminuria and high serum creatinine (Scr). Recent clinical studies have found that uric acid-lowering therapy (such as allopurinol) could reduce urinary albumin excretion rates (UAER) and Scr, increase eGFR, and thus reduce kidney damage in patients with diabetes. Therefore, this meta-analysis [PROSPERO CRD42021274465] intended to evaluate the efficacy and safety of allopurinol in patients with diabetes mellitus.

METHODS

We thoroughly searched five electronic resource databases for randomized controlled trials (RCTs) that compared the efficacy and safety of allopurinol versus conventional treatment or placebo for the treatment of patients with diabetes mellitus. Predetermined outcomes were considered continuous variables, mean difference (MD) was used for the determination of effect size (standardized mean difference [SMD] was used to determine the effect size when there were different evaluation criteria in different articles), and the corresponding 95% confidence interval (CI) was calculated. All outcome measures were analyzed using a random-effects model for data analysis.

RESULTS

Ten eligible trials with a total of 866 participants were included in the meta-analysis. Allopurinol was more effective in decreasing serum uric acid (SUA) levels compared with conventional treatment (p = 0.0001) or placebo (p < 0.00001). Moreover, the levels of 24-hour urine protein were significantly lower in the allopurinol group (p < 0.00001). The subgroup analysis of Scr showed that the Scr of patients with an allopurinol treatment duration of fewer than six months was significantly lower than that of the control group (p = 0.03). No significant difference in adverse events (AEs) was identified between the treatment and control groups.

CONCLUSIONS

Our meta-analysis of RCTs showed that oral administration of allopurinol effectively reduced SUA levels in patients with diabetes, and patients' renal function was protected. More RCTs with larger sample sizes and higher quality are needed to clarify the role of allopurinol use in decreasing blood pressure, maintaining blood glucose levels, and improving renal function in patients with diabetes.

Garlic and allopurinol alleviate the apoptotic pathway in rats' brain following exposure to fipronil insecticide

Fipronil can cause oxidative tissue damage and apoptosis. Our goal is to evaluate the antiapoptotic impact of garlic or allopurinol against fipronil neurotoxicity. Thirty-six mature male albino rats were separated into control, garlic aqueous extract (500 mg/kg), allopurinol (150 mg/L in their drinking water), fipronil (13.277 mg/kg), garlic+fipronil, and allopurinol+fipronil. Our results revealed that fipronil induced a significant increase in brain malondialdehyde, protein carbonyl levels as well as enzymatic antioxidant activities (superoxide dismutase, catalase, glutathione peroxidase, and xanthine oxidase), but glutathione-S-transferase recorded a significant decrease as compared to the control. In addition, fipronil significantly up-regulated the brain pro-apoptotic (Bax) and caspase -3 mRNA gene expression and induced DNA fragmentation but caused down-regulation in anti-apoptotic (Bcl-2) mRNA genes expression. Interestingly, co-administration with garlic or allopurinol improved the lipid peroxidation, antioxidant disturbance, and apoptosis induced by fipronil in the brain tissues. In conclusion, garlic or allopurinol reduced fipronil-induced apoptosis and reduced oxidative tissue damage, most likely through enhancing the tissue antioxidant defense system.

Persistence with urate-lowering therapy in Australia: A longitudinal analysis of allopurinol prescriptions

AIM

Gout is the most common form of inflammatory arthritis in men. Despite the availability of effective urate-lowering therapies (ULT), the management of gout is suboptimal due to poor persistence with ULT. This study examined national prescribing patterns of ULT to determine persistence with allopurinol in Australia.

METHODS

A 10% sample of the Australian Pharmaceutical Benefits Scheme dispensing claims database was used to identify individuals initiated on allopurinol between April 2014 and December 2019. The number of allopurinol scripts dispensed was used to estimate persistence with allopurinol. Persistence was defined as the number of months from initiation until discontinuation (last prescription with no further scripts acquired for a period thereafter). Kaplan-Meier curves were used to examine persistence, while Cox regression analysis was used to examine the influence of gender, concomitant colchicine and age.

RESULTS

The largest drop in persistence occurred immediately after initiation, with 34% of patients discontinuing allopurinol 300-mg therapy in the first month. Median persistence with allopurinol 300 mg was 5 months (95% confidence interval 4.76-5.24), with around 63% of individuals not persisting with this therapy for more than 12 months. Concomitant prescription of colchicine on the day of allopurinol initiation only occurred in 7% of allopurinol initiations. No increase in persistence was observed for those co-prescribed colchicine.

CONCLUSION

Persistence with allopurinol was poor. More effective methods targeting prescribers, patients and systems are required to promote persistence with allopurinol. Improving persistence to allopurinol is an important public health goal given the proven potential of this medication to eliminate gout.

Urine Xanthine Crystals in Hematologic Malignancies with Tumor Lysis Syndrome

Tumor lysis syndrome (TLS) is a metabolic disorder caused by massive tumor lysis. Hypouricemic agents are administered to prevent TLS-related hyperuricemia and renal failure. We experienced three cases of urine xanthine crystals during TLS in patients with hematologic malignancies who received prophylactic febuxostat. Yellowish and pinkish deposits were observed in urinary tract catheters and urinary bags. Urine microscopy revealed that the deposits were xanthine crystals. In rapid tumor lysis, inhibition of xanthine oxidase can cause xanthine accumulation and urine xanthine crystallization. During TLS, urine xanthine crystals may be overlooked, so careful observation and management are required to avoid xanthine nephropathy.

Unusual drug reaction with features of colchicine toxicity in a patient on colchicine and allopurinol

A 58-year-old woman was admitted for heart failure and concern for cardiogenic shock. The patient had been recently placed on colchicine and allopurinol, 4 months and 3 weeks, respectively, prior to admission. Upon admission, she had a cutaneous eruption that had started abruptly several days after allopurinol initiation. It included multiple erythematous papules with scant scale on the forearms and numerous erythematous papules on the legs. Because of the varied morphologic presentation, biopsies from both the thigh and forearm were performed for a suspected drug reaction. The specimen from the thigh showed a superficial-dermal, band-like lymphocytic infiltrate with dyskeratosis and numerous intraepidermal mitotic figures predominantly in metaphase. In addition, there were neutrophils with leukocytoclasia. The specimen from the forearm showed superficial perivascular lymphocytic inflammation and intraepidermal dyskeratosis with mitotic figures similar to the thigh biopsy specimen but without a dermal neutrophilic infiltrate. An unusual drug eruption with features of colchicine toxicity was favored. Colchicine toxicity is not a commonly encountered clinical scenario and cutaneous findings have only rarely been described. Herein we report an exceedingly rare case of an unusual drug reaction with "colchicine figures" (i.e., ring-shaped mitotic figures arrested in metaphase) consistent with colchicine toxicity.

Effects of Allopurinol as a xanthine oxidase inhibitor on depressive-like behavior of rats and changes in serum BDNF level

Background

Depression is a psychiatric disorder characterized by low mood and loss of interest in daily activities. Allopurinol, a xanthine oxidase blocker, is widely administered for the treatment of hyperuricemia. Recently, its effects on serotonin and depressive like behaviors have been reported. On the other hand, the level of brain-derived neurotrophic factor (BDNF), a protective and regenerative neurotrophic, has been increased by many antidepressants. The purpose of this study was to evaluate the antidepressant effects of allopurinol and changes in serum level of BDNF compared to those of fluoxetine.

Methods

Thirty-five male Wistar albino rats divided into five groups (control, 10 mg/kg fluoxetine, 25, 50 and 100 mg/kg allopurinol; n = 7 per group), that received all treatments intraperitoneally, every day. Forced swimming tests (FST), tail suspension test (TST) and open field test (OFT) were performed after 21 days of drug administration. Finally, the serum BDNF levels were measured using the sandwich ELISA method.

Results

All doses of allopurinol and fluoxetine reduced the duration of immobility time in FST and TST. No significant changes were observed in the number of lines crossed in OFT between either allopurinol or fluoxetine groups and control group. Serum level of BDNF were significantly higher in fluoxetine and allopurinol 50 and 100 mg/kg groups.

Conclusions

Long-term administration of allopurinol 50 and 100 mg/kg have shown antidepressant effects in behavioral tests along with an increase in the amount of serum BDNF concentration. The OFT results suggested that allopurinol did not have any significant effects on motor activity. The increased serum level of the BDNF in the allopurinol group was correlated with FST and TST results. However, it is still not clear whether the antidepressant effects of allopurinol are due to a direct effects on serotonin and/or BDNF or an indirect effect related to its xanthin oxidase inhibition.

Simple Application and Adherence to Gout Guidelines Enables Disease Control: An Observational Study in French Referral Centres

Background: In a context of therapeutic inertia, the French Society of Rheumatology (SFR) published its first recommendations on gout in 2020, which were deliberately simple and concise. The objectives of the study were to determine the profile of patients referred to French gout-expert centres, and to examine the results of their management and the factors leading to those results. Methods: Three hundred patients attending a first visit for gout management in three French referral centres were retrospectively and randomly included in this multicentre observational study. Visits were performed at baseline (M0) and scheduled for month 6 (M6), month 12 (M12), and month 24 (M24). Results: Patients were 81% male and had a mean age 62.2 ± 15.2 years. Management followed French recommendations after the baseline visit in 94.9% of cases. SU levels were below 6.0 mg/dL in 59.4% of patients at M6, 67.9% at M12, and 78.6% at M24, with increasing clinical improvement (i.e., flare decrease) over 2 years of follow-up. At M24, 50% of patients were treated with allopurinol (313 ± 105 mg/d), which exceeded renal restrictions of doses in 61.5% of them, and 48.2% received febuxostat (84 ± 36 mg/d). The need for a sufficient dosage of ULT was the only predictive factor found for successful achievement of SU levels < 6.0 mg/dL at a given visit. Conclusions: Simple application of gout-management guidelines is feasible in clinical practice and is efficient, with a majority of patients achieving SU targets and clinical improvement.

Evaluation of the therapeutic role of allopurinol on Bisphenol S gastric and renal toxicity in adult male albino rats: An in vivo study

Bisphenol S (BPS) is used as an alternative to bisphenol A (BPA) in polycarbonate plastics, epoxy resins and thermal receipt sheet manufacturing. We examined the toxic effects of BPS on gastric and renal functions, as well as the efficacy of allopurinol as a treatment. Albino rats were given only BPS (30 and 120 mg/kg BW/day) and some were treated with allopurinol prior to sacrifice. Gastric and renal specimens were evaluated histologically and immunohistochemically and blood from the tail vein was analysed for levels of gastrin, uric acid (UA), erythropoietin and 8-deoxyguanosine (8-OHdG) levels. Gastrin levels decreased while erythropoietin, UA and 8-OHdG levels increased significantly. The severity of gastric and renal damage observed in BPS-treated animals increased with increasing doses. The mean percentage of COX-2 immunoreactivity and the mean number of CD45 immunoreactive cells was significantly increased in the stomach and kidney of BPS rats. Allopurinol ameliorated the biochemical, histological and immunohistochemical alterations induced by BPS, with superior protection at lower doses. Allopurinol can reverse the effects of BPS on the stomach and kidneys.

HLA-A*24:02 increase the risk of allopurinol-induced drug reaction with eosinophilia and systemic symptoms in HLA-B*58:01 carriers in a Korean population; a multicenter cross-sectional case-control study

Background

HLA-B*58:01 is a well-known risk factor for allopurinol-induced severe cutaneous adverse reactions (SCARs). However, only a minority of HLA-B*58:01 carriers suffer SCARs after taking allopurinol. The aim of this study was to investigate subsidiary genetic markers that could identify those at further increased risk of developing allopurinol-induced drug reaction with eosinophilia and systemic symptoms (DRESS) in subjects with HLA-B*58:01.

Methods

Subjects with B*58:01 were enrolled (21 allopurinol-induced DRESS and 52 allopurinol-tolerant control). HLA-A, -B, -C and -DRB1 alleles were compared. Comparison of risk between HLAs and allopurinol-induced SCAR in separate populations was performed to support the results. Kruskal-Wallis test, Pearson's chi-square test, Fisher's exact test and binary logistic regression were used to analyze the risk of SCAR development.

Results

Frequencies of A*24:02 (71.4 vs. 17.3%, p < 0.001, odds ratio [OR] = 12.0; 95% confidence interval [CI], 3.6-39.2) were significantly higher in B*58:01 (+) DRESS than B*58:01 (+) tolerant controls. In addition, DRB1*13:02 further increased the risk of DRESS. The phenotype frequency of A*24:02/DRB1*13:02 was significantly higher in the B*58:01 (+) DRESS group than in the B*58:01 (+) tolerant controls (52.4% vs. 5.8%, p < 0.001, OR, 66.0; 95% CI, 6.1-716.2). In 2782 allopurinol user cohort, the overall prevalence of DRESS was 0.22%, which increased to 1.62% and 2.86% in the presence of B*58:01 and B*58:01/A*24:02, respectively.

Conclusion

The additional secondary screening with A*24:02 and DRB1*13:02 alleles may identify those at further increased risk of allopurinol-induced DRESS in B*58:01 carriers.

Ranolazine Versus Allopurinol for Eligible Symptomatic Patients With a History of Angioplasty: Comparative Efficacy Study

Background

Recurrent angina, which is defined as a return of chest pain or chest discomfort, occurs in many patients undergoing coronary interventions.

Objective

This study aims to compare the antianginal efficacy of ranolazine versus allopurinol for eligible symptomatic patients with a history of angioplasty.

Methods

A total of 62 eligible symptomatic patients with a history of angioplasty were randomly allocated into two groups. For group A, 300 mg of allopurinol was administered twice daily, while for group B, 1000 mg of ranolazine daily was prescribed for a duration of 4 weeks. An initial screening visit was done for all participants where patients’ medical history was recorded and a physical examination was given; electrocardiography, blood pressure, and heart rate measurements were done as well. The patients were also given a blood and exercise test. At the end of the medication period, participants were revisited, and the tests were done again. All the required data were collected via a researcher-made form, and data analysis was conducted using SPSS. The study was approved by a formal ethics committee.

Results

The mean age of participants in the two groups (A and B) was 57.36 (SD 8.36) and 60.27 (SD 9.17) years, respectively. Among the 62 patients, 34 (59%) were men, while 28 (41%) were women. Creatinine, fasting blood sugar, C-reactive protein, N-terminal prohormone of brain natriuretic protein, uric acid, white blood cell, and hemoglobin levels of participants were not significantly different between groups (P>.05). Both allopurinol and ranolazine increased the total exercise time and decreased the ST depression of the patients. Additionally, they both improved the chest pain severity and Duke Treadmill Score of patients. At the same time, ranolazine had a statistically greater effect on ST depression reduction (mean 2.64, SD 0.74 vs mean 1.57, SD 0.49), while allopurinol showed better efficacy in reducing chest pain severity (mean 1.86, SD 0.37 vs mean 0.59, SD 0.21) and the Duke Treadmill Score (mean –14.77, SD 3.65 vs mean –6.88, SD 1.93).

Conclusions

Based on the results, the antianginal efficacy of allopurinol and ranolazine was approved but with different effects on ST depression, chest pain severity, and the Duke Treadmill Score. Therefore, the precise differences in their effects need to be explored further.

Cardiovascular risk associated with allopurinol or benzbromarone treatment in patients with gout

Background:

In previous studies, cardiovascular (CV) risk was increased in patients with gout. The effects of uric acid–lowering therapy on CV risk in gout patients have been investigated in numerous studies; however, allopurinol and benzbromarone have rarely been compared.

Objectives:

To compare CV risk based on allopurinol and benzbromarone treatment in Korean gout patients.

Design:

A nationwide population-based retrospective cohort study.

Methods:

We used South Korea database of the Health Insurance Review and Assessment (HIRA) service to identify gout patients ⩾18 years of age who newly started allopurinol or benzbromarone between 2009 and 2015. The primary outcome of the study was the occurrence of a composite CV endpoint, which included coronary revascularization, hospitalization due to myocardial infarction, ischemic stroke, and transient ischemic attack. Cox proportional hazard regression analysis and Kaplan–Meier curves were used for analysis.

Results:

The study included 257,097 allopurinol initiators and 7868 benzbromarone initiators. Compared with allopurinol initiators, the adjusted hazard ratio (aHR) of the composite CV endpoint of benzbromarone initiators was 1.01 [95% confidence interval (CI): 0.83−1.21], which was not significantly different. The results did not change even when 1:3 propensity score matching was performed for baseline characteristics. In subgroup analysis of high-risk patients with CV disease, significant difference was not observed between allopurinol and benzbromarone initiators.

Conclusion:

In this study, significant difference was not found in CV risk between allopurinol and benzbromarone initiators. In the high-CV-risk group, the incidence of CV events did not differ between allopurinol and benzbromarone initiators.

Clinical features, treatment outcomes and prognostic factors of allopurinol-induced DRESS in 52 patients

WHAT IS KNOWN AND OBJECTIVE

Allopurinol-induced drug reaction with eosinophilia and systemic symptoms (DRESS) is a rare but serious and potentially life-threatening drug hypersensitivity syndrome. In this study, we aimed to investigate the clinical features, treatment outcomes, and prognostic factors of allopurinol-induced DRESS.

METHODS

Case reports of allopurinol-induced DRESS published by China from January 2000 to August 2021 were retrieved from CNKI, Wan Fang, VIP, and PubMed databases for analysis.

RESULTS AND DISCUSSION

This study included 52 patients, consisting of 41 (78.8%) males and 11 (21.2%) females (M:F = 3.7:1). The mean of age was 56.1 ± 17.1 years (range: 18-86 years). The mean of latency periods was 24.6 ± 15.0 days (range:1-63 days). Most patients presented with fever, cutaneous eruption, eosinophilia, lymphadenopathy, and facial edema. 36/52 (69.2%) patients showed two or more internal organs involved. Liver and kidney injuries were the most common visceral manifestation. Pulmonary involvement (34.6%), cardiac involvement (25.0%) and gastrointestinal involvement (21.2%) were relatively less known but severe complications. 2/52 (3.8%) patients showed nervous system involved, presenting as leukoencephalopathy or peripheral neuropathy. 2/52 (3.8%) patients presented with secondary hemophagocytic lymphohistiocytosis.1/52 (1.9%) patient developed pure red cell aplasia and 1/52 (1.9%) patient developed painless thyroiditis. HLA*B 58:01 allele was tested in 18/52 (34.6%) patients. 16/18 (88.9%) cases were positive. 48/52 (92.3%) patients were treated with systemic corticosteroids. 16/52 (30.8%) patients were cured, 23/52 (44.2%) patients received partial recovery, and 13/52 (25.0%) patients were died. Septic shock, gastrointestinal bleeding and multiple organ failure were the leading causes of death. Advanced age, underlying cardiovascular disease, chronic kidney disease and high dose of allopurinol, infection and internal organ involvement (including kidney, heart, lung and gastrointestinal tract) were risk factors for death.

WHAT IS NEW AND CONCLUSION

We explored clinical features, treatment outcomes and prognostic factors of 52 allopurinol-induced DRESS cases in China. Ethnicity, especially Han Chinese, and positive HLA-B*58:01 allele are the clearest risk factors so far. Advanced age, underlying cardiovascular disease, chronic kidney disease and high dose of allopurinol, infection and internal organ involvement (including kidney, heart, lung and gastrointestinal tract) were associated with poorer outcomes. Early identification and discontinuation of the causative drug are crucial to the management of DRESS. For patients with severe disease, corticosteroids are recommended as the first-line therapy. However, further studies are needed to address diagnostic criteria of DRESS for early diagnosis, as well as to develop standardized corticosteroid treatment regimens.

The Prospective Effect of Allopurinol on the Oxidative Stress Index and Endothelial Dysfunction in Covid-19

SARS-CoV-2 by the direct cytopathic effect or indirectly through the propagation of pro-inflammatory cytokines could cause endothelial dysfunction (ED) and oxidative stress (OS). It has been reported that OS is triggered by various types of viral infections, including SARS-CoV-2. Into the bargain, allopurinol is regarded as a potent antioxidant that acts through inhibition of xanthine oxidase (XO), which is an essential enzyme of purine metabolism. Herein, the present study aimed to find the potential protective effects of allopurinol on the biomarkers of OS and ED in patients with severe Covid-19. This single-center cohort study recruited 39 patients with mild-moderate Covid-19 compared with 41 patients with severe Covid-19. Nineteen patients with severe Covid-19 were on the allopurinol treatment because of underlying chronic gout 3 years ago compared with 22 Covid-19 patients not on this treatment. The recruited patients were allocated into three groups: group I, mild-moderate Covid-19 on the standard therapy (n = 39); group II, severe Covid-19 patients on the standard therapy only (n = 22); and group III, severe Covid-19 patients on the standard therapy plus allopurinol (n = 19). The duration of the study was 3 weeks from the time of hospitalization till the time of recovery. In addition, inflammatory biomarkers (D-dimer, LDH, ferritin, CRP, procalcitonin), neutrophil-lymphocyte ratio (NLR), endothelin-1 (ET-1), uric acid and oxidative stress index (OSI), CT scan score, and clinical score were evaluated at the time of admission and discharge regarding the effect of allopurinol treatment adds to the standard treatment of Covid-19. Allopurinol plus standard treatment reduced LDH, ferritin, CRP, procalcitonin, and ET-1 serum level significantly (P < 0.05) compared with Covid-19 patients on standard treatment. Besides, neutrophil (%), lymphocyte (%), and neutrophil-lymphocyte ratio (NLR) were reduced in patients with severe Covid-19 on standard treatment plus allopurinol compared with Covid-19 patients on standard treatment alone (P < 0.01). OSI was higher in patients with severe Covid-19 than mild-moderate Covid-19 patients (P = 0.00001) at admission. At the time of discharge, the oxidative status of Covid-19 patients was significantly improved compared with that at admission (P = 0.01). In conclusion, Covid-19 severity is linked with high OS and inflammatory reaction with ED development. High uric acid in patients with severe Covid-19 is correlated with high OS and inflammatory biomarkers. Allopurinol with standard treatment in patients with severe Covid-19 reduced oxidative and inflammatory disorders with significant amelioration of ED and clinical outcomes.

Functionalized Allopurinols Targeting Amyloid-Binding Alcohol Dehydrogenase Rescue Aβ-Induced Mitochondrial Dysfunction

Alzheimer's disease (AD) is the most common dementia affecting one in nine people over 65. Only a handful of small-molecule drugs and the anti-β amyloid (Aβ) antibody aducanumab are approved to treat AD. However, they only serve to reduce symptoms of advanced disease. Novel treatments administered early in disease progression before the accumulation of Aβ and tau reaches the threshold where neuroinflammation is triggered and irreversible neuronal damage occurs are more likely to provide effective therapy. There is a growing body of evidence implying that mitochondrial dysfunction occurs at an early stage of AD pathology. The mitochondrial enzyme amyloid-binding alcohol dehydrogenase (ABAD) binds to Aβ potentiating toxicity. Moreover, ABAD has been shown to be overexpressed in the same areas of the brain most affected by AD. Inhibiting the Aβ-ABAD protein-protein interaction without adversely affecting normal enzyme turnover is hypothesized to be a potential treatment strategy for AD. Herein, we conduct structure-activity relationship studies across a series of functionalized allopurinol derivatives to determine their ability to inhibit Aβ-mediated reduction of estradiol production from ABAD. The lead compound resulting from these studies possesses potent activity with no toxicity up to 100 μM, and demonstrates an ability to rescue defective mitochondrial metabolism in human SH-SY5Y cells and rescue both defective mitochondrial metabolism and morphology ex vivo in primary 5XFAD AD mouse model neurons.

Allopurinol use and the risk of dementia: A meta-analysis of case-control studies

BACKGROUND

This study aimed to compare the risk of dementia between exposed to allopurinol and not exposed to allopurinol in persons who had gout and/or hyperuricemia.

METHODS

The meta-analysis was conducted to select case-control research written in English through the help of PubMed and Web of Science. The pooled odds ratio (OR) with 95% confidence interval based on the fixed-effect model was applied to compare the allopurinol exposure among cases (subjects with dementia) and controls (subjects without dementia).

RESULTS

A total of 4 case-control studies relating the allopurinol exposure to the risk of dementia were identified. The study duration was from 9 to 14 years. The number of study persons was from 3148 to 137,640. The male percentage of study subjects was from 36.9 to 62.5. The mean age of study persons was from 72.3 to 78.7 years. Overall, the odds of the allopurinol exposure among cases were lower than the odds of the allopurinol exposure among control subjects (OR = 0.91, 95% confidence interval = 0.87-0.95, P < .001). The heterogeneity between these eligible studies was low (I² = 0%). The sensitivity analysis revealed that after excluding the studies with concern, the pooled OR did not achieve statistical significance.

CONCLUSIONS

This is the first meta-analysis to report that there is a negative relationship between the allopurinol exposure and the risk of dementia. Although the results favor the hypothesis, currently it is unable to draw strong conclusions about the protective effect of allopurinol against dementia due to inclusion of only a few eligible studies. Randomized controlled trials are needed to explore the relationship between allopurinol exposure and the probability of dementia.

Allopurinol Use and the Risk of Type 2 Diabetes Mellitus: A Meta-Analysis of Cohort Studies

Objective

To assess whether there is a relation between allopurinol use and the probability of type 2 diabetes mellitus (T2DM) in persons with gout and/or hyperuricemia.

Methods

According to the PRISMA 2020 guidelines, a meta-analysis was performed by searching literature published from 2000 to 2021 in two electronic databases (Ebscohost and PubMed). The end point was set as a new diagnosis ofT2DM between people with the use of allopurinol and people with non-use of allopurinol. The random-effects model was performed to evaluate the pooled hazard ratio (HR) with 95% confidence interval (CI) for T2DM associated with allopurinol use.

Results

Three cohort studies could meet the inclusion criteria in the meta-analysis. There was a high heterogeneity of the outcome between studies (I² = 99%). The research duration ranged from 13 to 16 years. The subject number in each work ranged from 1114 to 138,652. A meta-analysis disclosed that there was not an association between allopurinol use and the risk of developing T2DM (pooled HR = 1.01 and 95%CI = .55–1.84).

Conclusions

The meta-analysis shows that no correlation is detected between allopurinol use and the risk of T2DM in individuals with gout and/or hyperuricemia. Because there are not enough eligible studies, the strength of evidence in our meta-analysis is weak. More cohort studies are needed to determine an association between use of allopurinol and the probability of T2DM for individuals with gout and/or hyperuricemia.

Case Report: Azathioprine: An Old and Wronged Immunosuppressant

Mycophenolate rapidly substituted azathioprine (AZA) in transplant immunosuppression regimens since the 1990s, when early clinical trials indicated better outcomes, although opposite results were also observed. However, none of these trials used the well-established optimization methods for AZA dosing, namely, thiopurine methyltransferase pharmacogenetics combined with monitoring of the thiopurine metabolites 6-thioguanine nucleotides (6-TGN) and 6-methylmercaptopurine (6-MMP). Resistance to optimize AZA therapy remains today in transplant therapy, despite the fact that thiopurine metabolite testing is being used by other medical disciplines with evident improvement in clinical results. In a previous analysis, we found that active 6-TGN metabolites were not detectable in about 30% of kidney transplant patients under continuous use of apparently adequate azathioprine dosage, which demonstrates the need to monitor these metabolites for therapeutic optimization. Two of four case studies presented here exemplifies this fact. On the other hand, some patients have toxic 6-TGN levels with a theoretically appropriate dose, as seen in the other two case studies in this presentation, constituting one more important reason to monitor the AZA dose administered by its metabolites. This analysis is not intended to prove the superiority of one immunosuppressant over another, but to draw attention to a fact: there are thousands of patients around the world receiving an inadequate dose of azathioprine and, therefore, with inappropriate immunosuppression. This report is also intended to draw attention, to clinicians using thiopurines, that allopurinol co-therapy with AZA is a useful therapeutic pathway for those patients who do not adequately form active thioguanine metabolites.

Prevalence of Patients Receiving Urate-Lowering Medicine in Greenland and Denmark: A Cross-Sectional Case-Control Study

This study estimates the age- and sex-specific prevalence of patients receiving urate-lowering therapy (ULT) in Greenland and compares the results with estimates in Denmark. Characteristics of patients receiving ULT in Greenland were compared to age- and sex-matched controls. The study was designed as a cross-sectional case−control study based on nationwide data from medical and population registers in Greenland and Denmark. The prevalence of patients receiving ULT was significantly lower in Greenland (0.55%) compared to Denmark (1.40%) (p < 0.001). In both countries, the prevalence increased with age and was higher among men compared to women. In Greenland, patients receiving ULT were more often overweight, and more frequently received blood glucose-, lipid-, and blood pressure-lowering medicine including diuretics compared to age- and sex-matched controls. The prevalence of patients receiving ULT was significantly lower in Greenland compared to Denmark. Common life-style related risk factors for hyperuricemia and gout were observed frequently among ULT-treated patients compared to controls. Along with an increasing prevalence of lifestyle-related diseases in Greenland, the prevalence of patients receiving ULT may increase in the years to come. More focus on detection and management of hyperuricemia and gout in Greenland is warranted to improve quality of health care.

Pharmacokinetics, pharmacodynamics, and safety of verinurad with and without allopurinol in healthy Asian, Chinese, and non-Asian participants

Verinurad is a selective inhibitor of uric acid transporter 1 (URAT1). Here, we assessed the safety, pharmacokinetics, and pharmacodynamics of verinurad + allopurinol and verinurad monotherapy in healthy participants. Studies 1 (NCT03836599) and 2 (NCT02608710) were randomized Phase 1 studies. In Study 1, 12 healthy Asian participants received 24 mg verinurad + 300 mg allopurinol or placebo, and 9 healthy Chinese participants received 12 mg verinurad + 300 mg allopurinol. In Study 2, 24 healthy non-Asian male participants received 12 mg verinurad. Safety analyses included assessment of adverse events (AEs). Pharmacokinetic parameters included maximum concentration (Cmax ) and area under plasma concentration-time curve (AUC) over 24 h (AUCτ ). Pharmacodynamic parameters included percentage change from baseline (day -1) in serum uric acid (sUA) and urinary uric acid (uUA). There were no serious AEs or deaths in either study. In Study 1, steady-state geometric mean (gCV%) Cmax and AUCτ values of verinurad after 7 days' dosing were 73.6 (29.0) ng/mL and 478 (18.4) ng·h/mL, respectively, in healthy Asian participants, and 42.0 (40.1) ng/mL and 264 (36.1) ng·h/mL, respectively, in healthy Chinese participants; in Study 2, gCV% values were 36.3 (36.5) ng/mL and 271 (31.0) ng·h/mL, respectively. sUA decreased and uUA excretion increased compared with baseline following verinurad + allopurinol (Study 1) or verinurad (Study 2). When accounting for dose, the steady-state pharmacokinetics of verinurad following multiple dosing were comparable between healthy Asian and Chinese participants and healthy non-Asian participants. Verinurad treatments were well tolerated, including at higher verinurad exposures than previously evaluated after repeated dosing.

Effect of Different Molecular Weights of Chitosan on Formulation and Evaluation of Allopurinol-Loaded Nanoparticles for Kidney Targeting and in Management of Hyperuricemic Nephrolithiasis

Present research study was conducted to formulate kidney-targeted allopurinol (AO)-loaded chitosan nanoparticles (ANPs) for management of hyperuricemic related nephrolithiasis. Different molecular weights of chitosan were used for fabricating ANP formulation by adopting modified ionotropic gelation method. The prepared batches were than evaluated for particle size analysis, entrapment efficiency, transmission electron microscopy, X-ray diffraction, Differential Scanning Calorimetry, in vitro release and in vivo animal study. The in vivo study depicted that post 2 h of administration of different formulations and pure drug; ANPs prepared from low molecular weight chitosan showed maximum concentration of AO in kidney signifying successful kidney targeting of drug (25.92 fold) whereas no or very less amount of AO was seen in other animal groups. Effectiveness (p < 0.01) of formulation in management of hyperuricemia-associated nephrolithiasis was also evaluated via estimation of urine pH and serum and urine uric acid levels of mice. Further histological study was also performed on kidney samples which again affirmed these results. Present investigation demonstrated that ANPs prepared from low MW chitosan depicted maximum kidney-targeting ability that might be due to its specific uptake by the kidneys as well as its higher solubility than other two polymers, which results in enhanced release rate from the formulation and also offers an efficient strategy for the management of hyperuricemic nephrolithiasis.

Comparison of Benzbromarone and Allopurinol on Primary Prevention of the First Gout Flare in Asymptomatic Hyperuricemia

Objectives. Whether uric acid-lowering agent use in asymptomatic hyperuricemia can reduce the development of the first gout flare remains unsettled. The goal of the present research was to test the efficacy of benzbromarone and allopurinol on primary prevention of the first gout flare in persons with asymptomatic hyperuricemia in Taiwan. Methods. One observational cohort study was constructed to examine the 2001−2015 dataset adapted from the National Health Insurance Program of Taiwan containing the claims data of 2 million beneficiaries. Asymptomatic hyperuricemia was considered as individuals on uric acid-lowering therapy who did not have gout flares. Individuals aged 20−84 without gout flares who had the use of benzbromarone alone were assigned into a benzbromarone group. Individuals ages 20−84 without gout flares who had the use of allopurinol alone were assigned into an allopurinol group. The final study included 6111 pairs of 1:1 propensity score-matched individuals from both benzbromarone and allopurinol groups. The end point was assigned as individuals who were newly diagnosed with their first gout flare. The incidence rate of the first gout flare was estimated between the benzbromarone and allopurinol groups. A Cox proportional hazards regression model was applied to explore the hazard ratio and 95% confidence interval of the first gout flare related to benzbromarone use and allopurinol use. Results. The incidence rate of the first gout flare was lower in the benzbromarone group compared with an allopurinol group (3.29 versus 5.46 per 1000 person-months, incidence rate ratio = 0.60 and 95% confidence interval = 0.56−0.64). After adjustment for co-variables, the adjusted hazard ratio of the first gout flare was 0.63 (95% confidence interval = 0.59−0.68, p < 0.001) for the benzbromarone group when compared with the allopurinol group. Conclusion. People with asymptomatic hyperuricemia taking benzbromarone have a lower hazard of developing their first gout flare when compared with those taking allopurinol. Based on the medication safety, the therapeutic effects and the low price, with oral administration once daily, we suggest that benzbromarone should be the first drug of choice if clinicians are treating asymptomatic hyperuricemia.

Prevalence of Hypertension in Sudanese Patients With Gouty Arthritis

Background In this study, we aimed to study the frequency of hypertension in Sudanese patients with gouty arthritis attending the largest three tertiary hospitals in Khartoum and correlate it with serum uric acid levels. Methodology An observational, descriptive, cross-sectional, hospital-based study was conducted in rheumatology clinics in Khartoum state, Sudan, from August 2020 to January 2021 involving 100 participants. Data were collected, prepared, and analyzed using SPSS version 25.0 (IBM Corp., Armonk, NY, USA). Results In this study, 100 participants were enrolled. The majority were males (79%), with 45% of the participants in the age group of 61-75 years. Overall, 89% of participants had symptoms of gouty arthritis, with the knee being the most common joint affected in 27% of participants. Most participants had a uric acid level above the target (6 mg/dL). The most frequently used uric acid lowering agent was found to be allopurinol in 85% of the patients. Furthermore, among those with gouty arthritis, 51% had hypertension with nearly half being insufficiently controlled. The frequency of undiagnosed hypertension among the participants was found to be 19%, which was statistically significant among gouty arthritis patients (p-value < 0.0001). Upon further analysis of our hypertensive participants, 79.5% of males (n = 35) had high blood pressure levels, which was statistically significant as well (p-value = 0.005), with the highest prevalence being among the age group of 61-75 years. Of those who were hypertensive, 51% had a history of concomitant comorbidity. Overall, 90% of the hypertensive participants (n = 40) had joint symptoms. Moreover, serum uric acid level was above the target in 93% of the participants. Conclusions Hypertension was found to be the most frequently recognized comorbidity in gouty arthritic patients, with more than a third remaining undiagnosed. Moreover, the male gender was a significant risk factor for hypertension among the gouty arthritis participants. Nevertheless, most patients with high blood pressure levels had concurrent elevated uric acid levels.