Assessment on the use of allopurinol to improve safety and efficacy of mercaptopurine in pediatric patients with Acute Lymphoblastic Leukemia and Lymphoma during maintenance therapy

BACKGROUND

Mercaptopurine is an important component of acute lymphoblastic leukemia (ALL) and lymphoma (LLy) maintenance therapy. The 6-thioguanine nucleosides (6-TGN) are believed to be the primary contributor to myelosuppression and immunosuppressive effects, while 6-methylmercaptopurine (6-MMPN) is believed to be responsible for several toxicities including hepatotoxicity, pancreatitis, and hypoglycemia. Previous reports suggest the addition of allopurinol may reduce these toxicities.

AIMS

To assess the use of allopurinol to improve both safety and efficacy of mercaptopurine in pediatric patients with ALL and LLy during maintenance therapy. Secondary objectives included evaluating patient tolerability and skewed metabolism. In addition, we also analyzed mercaptopurine daily dose reduction upon allopurinol initiation.

METHODS AND RESULTS

The primary endpoint was time within goal ANC prior to and after initiation of allopurinol. Secondary endpoints included; improvement in selective toxicities (hepatotoxicity, pancreatitis, and hypoglycemia) and 6-MMPN to 6-TGN ratio prior to and after allopurinol initiation. In addition, an exploratory endpoint assessing mercaptopurine daily dose reduction prior to and after allopurinol initiation was included. Sixteen patients met inclusion criteria and 15 (94%) of which were included in this study. Median percent of maintenance days within goal ANC prior to and after initiation of allopurinol was 27.8 (IQR 22.6-44.9) and 41.6 (IQR 20.2-58.2) respectively. All patients experienced selective toxicities; 15 (100%) hepatotoxicity, 1 (7%) pancreatitis, and 3 (20%) hypoglycemia. Improvement of toxicities was seen in 13/15 (87%), 1/1 (100%), and 2/3 (67%) respectively. Average 6-MMPN:6-TGN ratio prior to allopurinol initiation was 304:1 and after, allopurinol initiation improved to 15:1, resulting in a 95% reduction. Average mercaptopurine dose prior to and after allopurinol initiation decreased by about 56% (63 to 28 mg/m2 /day).

CONCLUSION

Results suggest that the use of allopurinol in pediatric patients with ALL and LLy receiving mercaptopurine during maintenance therapy is both safe and effective.

Can Smartphone Notifications Help With Gout Management? A Feasibility Study

OBJECTIVE

This feasibility study aimed to assess the acceptability of using smartphone notifications to modify the medication beliefs of people with gout. We evaluated the feasibility and acceptability of a smartphone application using the Technology Acceptance Model. We explored adherence rate differences and outcomes between the intervention and control groups.

METHODS

Fifty-two patients with gout who were prescribed allopurinol were randomly assigned to either active control (n = 24) or intervention group (n = 28). Over 3 months, both groups used the study app on their smartphones. The active control group received notifications about general health advice, whereas the intervention group received adherence-targeted notifications. The feasibility and acceptability of the smartphone app was measured through semistructured interviews. Adherence rate was assessed through serum urate levels and missed doses at 3 timepoints: baseline, 3 months (post intervention), and 6 months (follow-up).

RESULTS

The smartphone app demonstrated high feasibility, with strong participant retention and compliance. The participants expressed high levels of satisfaction with the app's user-friendliness and content, highlighting its acceptability. Both groups showed a significant reduction in missed doses over time (P < 0.05), but no significant differences in serum urate levels were found between the groups. Patients who received adherence-targeted notifications reported finding it more convenient to take allopurinol and expressed higher overall treatment satisfaction throughout the study.

CONCLUSION

Adherence-targeted notifications have the potential to be an effective and scalable approach to supporting medication adherence in patients with gout. Further research is needed with larger samples to refine the components of the intervention and explore its optimal implementation.

Combination of allopurinol with Dahuang Mudan Tang significantly improve kidney function and alleviate oxidative stress and inflammation of chronic kidney disease stage Ⅰ-Ⅲ patients with hyperuricemia

OBJECTIVE

To evaluate the effect of Dahuang Mudan Tang (, DHMD) and allopurinol on the treatment of chronic kidney disease staged G1-G3b patients with hyperuricemia and to provide novel insights into the clinical management of chronic kidney disease complications.

METHODS

A total of 80 chronic kidney patients staged G1-G3b with hyperuricemia were randomly grouped to receive single allopurinol treatment (control) and combined treatment with DHMD (treated) for 8 weeks. The kidney function and proteinuria indicators of patients were compared between pre-and post-treatment. The oxidative stress and inflammation responses were evaluated by corresponding indicators and cytokines. The clinical efficiency rate and adverse reaction events were also summarized to assess the therapeutic efficiency and safety.

RESULTS

The kidney function and proteinuria of enrolled patients were alleviated after their therapies, behaved as the increasing estimated glomerular filtration rate and decreasing serum creatinine, serum uric acid, urea nitrogen, 24 h urine protein levels. On the other hand, the malondialdehyde level and pro-inflammation cytokines were suppressed by the therapies, and the superoxide dismutase was found to be significantly enhanced. Patients in the treated groups showed a better recovery in kidney function, proteinuria, oxidative stress, and inflammation response. Moreover, patients in the treated group showed a higher efficiency rate (95%) and fewer adverse reaction events (5%).

CONCLUSIONS

The combination of allopurinol with DHMD significantly promoted the recovery of chronic kidney disease stage G1-G3b patients with hyperuricemia, which can be considered a novel clinical therapeutic strategy.

Sustained xanthine oxidase inhibitor treat to target urate lowering therapy rewires a tight inflammation serum protein interactome

Background

Effective xanthine oxidoreductase inhibition (XOI) urate-lowering treatment (ULT) to target significantly reduces gout flare burden and synovitis between 1-2 years therapy, without clearing all monosodium urate crystal deposits. Paradoxically, treat to target ULT is associated with increased flare activity for at least 1 year in duration on average, before gout flare burden decreases. Since XOI has anti-inflammatory effects, we tested for biomarkers of sustained, effective ULT that alters gouty inflammation.

Methods

We characterized the proteome of febuxostat-treated murine bone marrow macrophages. Blood samples (baseline and 48 weeks ULT) were analyzed by unbiased proteomics in febuxostat and allopurinol ULT responders from two, independent, racially and ethnically distinct comparative effectiveness trial cohorts (n=19, n=30). STRING-db and multivariate analyses supplemented determinations of significantly altered proteins via Wilcoxon matched pairs signed rank testing.

Results

The proteome of cultured IL-1b-stimulated macrophages revealed febuxostat-induced anti-inflammatory changes, including for classical and alternative pathway complement activation pathways. At 48 weeks ULT, with altered purine metabolism confirmed by serum metabolomics, serum urate dropped >30%, to normal (<6.8 mg/dL) in all the studied patients. Overall, flares declined from baseline. Treated gout patient sera and peripheral blood mononuclear cells (PBMCs) showed significantly altered proteins (p<0.05) in clustering and proteome networks. CRP was not a useful therapy response biomarker. By comparison, significant serum proteome changes included decreased complement C8 heterotrimer C8A and C8G chains essential for C5b-9 membrane attack complex assembly and function; increase in the NLRP3 inflammasome activation promoter vimentin; increased urate crystal phagocytosis inhibitor sCD44; increased gouty inflammation pro-resolving mediator TGFB1; decreased phagocyte-recruiting chemokine PPBP/CXCL7, and increased monocyte/macrophage-expressed keratin-related proteins (KRT9,14,16) further validated by PBMC proteomics. STRING-db analyses of significantly altered serum proteins from both cohorts revealed a tight interactome network including central mediators of gouty inflammation (eg, IL-1B, CXCL8, IL6, C5).

Conclusions

Rewiring of inflammation mediators in a tight serum protein interactome was a biomarker of sustained XOI-based ULT that effectively reduced serum urate and gout flares. Monitoring of the serum and PBMC proteome, including for changes in the complement pathway could help determine onset and targets of anti-inflammatory changes in response to effective, sustained XOI-based ULT.Trial Registration: ClinicalTrials.gov Identifier: NCT02579096.

Stevens-Johnson Syndrome From Combined Allopurinol and Angiotensin-Converting Enzyme Inhibitors: A Narrative Review

Stevens-Johnson syndrome (SJS) is a severe and potentially debilitating skin reaction frequently related to medication use. Allopurinol and angiotensin-converting enzyme (ACE) inhibitors are commonly prescribed medications for prevalent health conditions worldwide, and their interaction associated with SJS warrants further investigation. A comprehensive literature search was performed to investigate cases as studies related to SJS occurring in patients with concomitant use of allopurinol and ACE inhibitors. We identified case reports and studies detailing hypersensitivity reactions, including SJS, attributed to a combination of allopurinol and ACE inhibitors. Despite the drug-drug interactions or lack thereof seen in patient populations, there is no definitive evidence of a pharmacokinetic interaction between allopurinol and ACE inhibitors. We were only able to find one case report specifically detailing SJS in a patient on combined ACE inhibitors and allopurinol. While the exact mechanism of the interaction is unclear, those reported cases of severe hypersensitivity reactions suggest a previous history of impaired renal function as a predisposing factor in the development of SJS. The potential risk of SJS with coadministration of ACE inhibitors and allopurinol is a drug-drug interaction that physicians should be aware of. This topic requires additional attention to determine if this drug combination should be avoided entirely in certain patients.

Allopurinol-Induced Toxic Epidermal Necrolysis

Toxic epidermal necrolysis (TEN) is a rare and life-threatening cutaneous disease, frequently triggered by drugs. Allopurinol is one of the most frequent drugs associated with TEN, which implies detachment of a significant amount of the body surface area (BSA) and has a high morbidity and mortality associated with it. We present the case of a 68-year-old female with a recent diagnosis of hyperuricemia who started treatment with allopurinol. A week later, she presented to the emergency department with an extensive maculopapular exanthema with blisters and skin detachment. After the exclusion of other etiologies, the diagnosis of allopurinol-induced TEN was made, with 35% of BSA involvement. Due to the severity of the clinical condition, she was admitted to intensive care and treated with corticoids that had no response. So, she was started on immunoglobulins and transferred to a burn unit. She developed sepsis with multiorgan failure and required supportive treatment. She was discharged after a month, and physical rehabilitation was needed. This clinical case highlights the severity of allopurinol hypersensitivity that may happen and the importance of an accurate diagnosis and treatment for this rare disease.

Drug-Induced Hypersensitivity Syndrome Accompanied With Acute Renal Failure With Hemodialysis: A Case Report and Literature Review

Drug-induced hypersensitivity syndrome (DIHS) is a severe type of cutaneous adverse event involving systemic organ failures. In some cases of DIHS, acute renal failure takes place, and it becomes necessary to perform hemodialysis. However, the clinical outcome of renal failure in the course of treatment of DIHS remains unclear. Herein, we report a case of DIHS complicated with acute renal failure, which requires hemodialysis. Furthermore, we also review the DIHS cases accompanied by acute renal failure with hemodialysis in the English case report literature.

Is the combination of linagliptin and allopurinol better prophylaxis against post-contrast acute kidney injury? A multicenter prospective randomized controlled study

BACKGROUND

Patients with diabetic kidney disease (DKD) are at increased risk to develop post-contrast acute kidney injury (AKI). Diabetic patients under dipeptidyl peptidase 4 inhibitors (DPP4Is) experience a lower propensity to develop AKI. We speculated that linagliptin as a single agent or in combination with allopurinol may reduce the incidence of post-contrast AKI in stage 3-5 chronic kidney disease (CKD) patients with underlying DKD.

METHODS

Out of 951 DKD patients eligible for this study, 800 accepted to sign informed consent. They were randomly allocated to 4 equal groups that received their prophylaxis for 2 days before and after radiocontrast. The first control group received N-acetyl cysteine and saline, the 2^nd received allopurinol, the 3^rd group received linagliptin, and the 4^th received both allopurinol and linagliptin. Post-procedure follow-up for kidney functions was conducted for 2 weeks in all patients.

RESULTS

20, 19, 14, and 8 patients developed post-contrast AKI in groups 1 through 4, respectively. Neither linagliptin nor allopurinol was superior to N-acetyl cysteine and saline alone. However, the combination of the two agents provided statistically significant renal protection: post-contrast AKI in group 4 was significantly lower than in groups 1 and 2 (p < 0.02 and <0.03, respectively). None of the post-contrast AKI cases required dialysis.

CONCLUSION

Linagliptin and allopurinol in combination may offer protection against post-contrast AKI in DKD exposed to radiocontrast. Further studies are needed to support this view.

TRIAL REGISTRATION CLINICALTRIALS.GOV

NCT03470454.

DRESS and Stevens-Johnson Syndrome Overlap Secondary to Allopurinol in a 50-Year-Old Man-A Diagnostic and Treatment Challenge: Case Report

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a drug reaction commonly related to eosinophilia, from uncertain epidemiology, and without consensus for diagnosis and treatment globally. It presents a great challenge in its management and is characterized by fever, lymphadenopathy, skin rash, and multisystemic involvement. An aggressive and difficult-to-manage clinical case is presented in a 50-year-old man with chronic kidney disease due to diabetes mellitus type 2 and systemic arterial hypertension, who developed an unusual variant similar to DRESS and Stevens-Johnson syndrome (SJS) overlap secondary to allopurinol, with skin manifestations without eosinophilia, but fulfilling clinical and laboratory criteria for DRESS and SJS syndrome.

Allopurinol versus Febuxostat: A New Approach for the Management of Hepatic Steatosis in Metabolic Dysfunction-Associated Steatotic Liver Disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) includes patients with hepatic steatosis and at least one of five cardiometabolic risk factors. Xanthine oxidase (XO) represents a treatment target for MASLD. We aimed to evaluate the effect of two xanthine oxidase inhibitors, allopurinol and febuxostat, plus lifestyle modifications compared to lifestyle modifications alone on improving steatosis. Ninety MASLD patients were assigned to one of three groups for three months. Patients with hyperuricemia were given either allopurinol 100 mg or febuxostat 40 mg daily, along with lifestyle modifications. The third control group was only given lifestyle modifications, excluding all patients with hyperuricemia due to ethical concerns. The primary outcome was to measure the change in the controlled attenuation parameter (CAP) score as an indicator of steatosis from baseline after three months. The secondary outcome was to measure the change in serum uric acid (SUA) three months from baseline. The study found that the CAP score decreased significantly in the allopurinol group (p = 0.009), but the decline in the febuxostat or lifestyle groups was non-significant (p = 0.189 and 0.054, respectively). The SUA levels were significantly reduced in both the allopurinol and febuxostat groups (p < 0.001), with no statistical difference between the two groups (p = 0.496).

The allopurinol metabolite, oxypurinol, drives oligoclonal expansions of drug-reactive T cells in resolved hypersensitivity cases and drug-naïve healthy donors

Allopurinol (ALP) is a successful drug used in the treatment of gout. However, this drug has been implicated in hypersensitivity reactions that can cause severe to life-threatening reactions such as Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). Individuals who carry the human leukocyte antigen (HLA)-B*58:01 allotype are at higher risk of experiencing a hypersensitivity reaction (odds ratios ranging from 5.62 to 580.3 for mild to severe reactions, respectively). In addition to the parent drug, the metabolite oxypurinol (OXP) is implicated in triggering T cell-mediated immunopathology via a labile interaction with HLA-B*58:01. To date, there has been limited information regarding the T-cell receptor (TCR) repertoire usage of reactive T cells in patients with ALP-induced SJS or TEN and, in particular, there are no reports examining paired αβTCRs. Here, using in vitro drug-treated PBMCs isolated from both resolved ALP-induced SJS/TEN cases and drug-naïve healthy donors, we show that OXP is the driver of CD8+ T cell-mediated responses and that drug-exposed memory T cells can exhibit a proinflammatory immunophenotype similar to T cells described during active disease. Furthermore, this response supported the pharmacological interaction with immune receptors (p-i) concept by showcasing (i) the labile metabolite interaction with peptide/HLA complexes, (ii) immunogenic complex formation at the cell surface, and (iii) lack of requirement for antigen processing to elicit drug-induced T cell responsiveness. Examination of paired OXP-induced αβTCR repertoires highlighted an oligoclonal and private clonotypic profile in both resolved ALP-induced SJS/TEN cases and drug-naïve healthy donors.

Therapeutic voyage of synthetic and natural xanthine oxidase inhibitors

Xanthine oxidase (XO) inhibitors are commonly used to treat gout, nephropathy, and renal stone diseases related to hyperuricemia. However, recent research has shown that these inhibitors may also have potential benefits in preventing vascular diseases, including those affecting the cerebrovasculature. This is due to emerging evidence suggesting that serum uric acid is involved in the growth of cardiovascular disease, and XO inhibition can reduce oxidative stress in the vasculature. There is a great interest in the development of new XO inhibitors for the treatment of hyperuricemia and gout. The present review discusses the many synthetic and natural XO inhibitors that have been developed which are found to have greater potency.

Implementing treat-to-target urate-lowering therapy during hospitalisations for gout flares

OBJECTIVES

To evaluate a strategy designed to optimise care and increase uptake of urate-lowering therapy (ULT) during hospitalisations for gout flares.

METHODS

We conducted a prospective cohort study to evaluate a strategy that combined optimal in-hospital gout management with a nurse-led, follow-up appointment, followed by handover to primary care. Outcomes, including ULT initiation, urate target attainment, and re-hospitalisation rates, were compared between patients hospitalised for flares in the 12 months post-implementation and a retrospective cohort of hospitalised patients from 12 months pre-implementation.

RESULTS

119 and 108 patients, respectively, were hospitalised for gout flares in the 12 months pre- and post-implementation. For patients with 6-month follow-up data available (n = 94 and n = 97, respectively), the proportion newly initiated on ULT increased from 49.2% pre-implementation to 92.3% post-implementation (age/sex-adjusted odds ratio (aOR) 11.5; 95% confidence interval (CI) 4.36-30.5; p < 0.001). After implementation, more patients achieved a serum urate ≤360 micromol/L within 6 months of discharge (10.6% pre-implementation vs. 26.8% post-implementation; aOR 3.04; 95% CI 1.36-6.78; p = 0.007). The proportion of patients re-hospitalised for flares was 14.9% pre-implementation vs. 9.3% post-implementation (aOR 0.53, 95% CI 0.22 to 1.32; p = 0.18).

CONCLUSION

Over 90% of patients were initiated on ULT after implementing a strategy to optimise hospital gout care. Despite increased initiation of ULT during flares, recurrent hospitalisations were not more frequent following implementation. Significant relative improvements in urate target attainment were observed post-implementation; however, for the majority of hospitalised gout patients to achieve urate targets, closer primary-secondary care integration is still needed.

Allopurinol-Induced Stevens-Johnson Syndrome (SJS)

Allopurinol is a commonly used medication that lowers uric acid production which is essential for gout treatment and prevention. Although many patients tolerate allopurinol therapy without severe complications; Stevens-Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) are life-threatening delayed hypersensitivity reactions that have been reported especially among Asian and African American patients. We describe a case of allopurinol-induced SJS in a 95-year-old Asian female. The patient started allopurinol 13 days prior to presenting to the emergency room (ER). On day 10 of therapy, the patient developed a diffuse erythematous desquamating rash which prompted her to visit the ER after 3 days from the rash onset. This case report describes a rare fatal hypersensitivity reaction that requires rapid identification and treatment in a multi-disciplinary setting.

Population pharmacokinetics, pharmacodynamics and pharmacogenetics modelling of oxypurinol in Hmong adults with gout and/or hyperuricemia

AIMS

The aim of this study was to quantify identifiable sources of variability, including key pharmacogenetic variants in oxypurinol pharmacokinetics and their pharmacodynamic effect on serum urate (SU).

METHODS

Hmong participants (n = 34) received 100 mg allopurinol twice daily for 7 days followed by 150 mg allopurinol twice daily for 7 days. A sequential population pharmacokinetic pharmacodynamics (PKPD) analysis with non-linear mixed effects modelling was performed. Allopurinol maintenance dose to achieve target SU was simulated based on the final PKPD model.

RESULTS

A one-compartment model with first-order absorption and elimination best described the oxypurinol concentration-time data. Inhibition of SU by oxypurinol was described with a direct inhibitory Emax model using steady-state oxypurinol concentrations. Fat-free body mass, estimated creatinine clearance and SLC22A12 rs505802 genotype (0.32 per T allele, 95% CI 0.13, 0.55) were found to predict differences in oxypurinol clearance. Oxypurinol concentration required to inhibit 50% of xanthine dehydrogenase activity was affected by PDZK1 rs12129861 genotype (-0.27 per A allele, 95% CI -0.38, -0.13). Most individuals with both PDZK1 rs12129861 AA and SLC22A12 rs505802 CC genotypes achieve target SU (with at least 75% success rate) with allopurinol below the maximum dose, regardless of renal function and body mass. In contrast, individuals with both PDZK1 rs12129861 GG and SLC22A12 rs505802 TT genotypes would require more than the maximum dose, thus requiring selection of alternative medications.

CONCLUSIONS

The proposed allopurinol dosing guide uses individuals' fat-free mass, renal function and SLC22A12 rs505802 and PDZK1 rs12129861 genotypes to achieve target SU.

Cardiovascular Safety Evaluation of Febuxostat and Allopurinol: Findings from the FDA Adverse Event Reporting System

BACKGROUND

Febuxostat and allopurinol are the most commonly used uric acid-lowering medications, and their safety is of great concern, especially the cardiovascular adverse reactions associated with febuxostat. We propose to study the cardiovascular toxicity of febuxostat and allopurinol using the FDA Adverse Event Reporting System (FAERS) database.

METHODS

A total of 64 quarters of FAERS data were downloaded from 2004 to 2019. Febuxostat- and allopurinol-related cardiovascular adverse events were extracted after data cleaning. Signal detection was conducted by reporting odds ratio (ROR) and proportional reporting ratio (PRR).

RESULTS

There were 2939 and 25,219 reports of febuxostat- and allopurinol-related cardiovascular adverse events (CVAEs), respectively. The most frequent CVAEs with febuxostat and allopurinol were edema peripheral (14.38%) and peripheral swelling (8.76%), respectively. In elderly gout patients, febuxostat is associated with an increased risk of heart failure, ischemic heart disease, hypertension, and cardiomyopathy. Febuxostat in combination with acetic acid derivatives nonsteroidal anti-inflammatory drug (NSAIDS) also increases the risk of cardiovascular adverse events.

CONCLUSIONS

Compared with allopurinol, febuxostat may increase cardiovascular toxicity in patients with gout.

Hepatic Safety of Febuxostat and Allopurinol for Gout Patients: A Systematic Review of Randomized Controlled Trial

Purpose

This study aims to systematically review the hepatic safety of febuxostat and allopurinol in adult gout patients.

Methods

We searched for information using the following databases: PubMed, Cochrane Library, and Scopus. The inclusion criteria were to review all randomized controlled trials (RCT) that compared allopurinol and febuxostat for adult gout patients that had an assessment of liver function outcomes. Non-English studies on case reports, case series, reviews, and abstracts only were excluded. We extracted information from the studies to answer the research question, ie, study design, publication year, population, sample size, patient characterization, duration, Jadad score, and liver function outcomes.

Results

We screened 512 publications from the databases and identified 11 studies that met the inclusion criteria. Ten out of 11 included studies were double-blind RCTs. In the majority of the included studies, no statistically significant differences were observed in terms of hepatic safety data between febuxostat and allopurinol. However, in studies where allopurinol titration was used, it posed a challenge to maintain blinding. Notably, consistent adverse events related to liver function findings were observed across all reviewed RCTs. These abnormal liver function test results sometimes led to study withdrawal based on the investigators' assessment. Nevertheless, the investigators classified most liver function test elevations as mild to moderate in severity.

Conclusion

Our analysis concluded that adult gout patients enrolled in the included RCTs exhibited similar hepatic safety profiles for both febuxostat and allopurinol treatment. Liver function abnormalities were identified in all RCTs included in this systematic review. Consequently, it is important for the product labeling information of both allopurinol and febuxostat to present and describe the current safety data to guide healthcare practitioners when prescribing these medications to patients. Pharmacovigilance and post-marketing pharmacoepidemiology data are essential in establishing the comprehensive safety profile.

Epidemiology and risk factors associated with gout control among adult Asians: a real-world retrospective cohort study

Background

Gout is associated with significant morbidity and mortality, yet suboptimal gout control remains a problem globally. Identifying the risk factors associated with poor gout control among patients in primary care allows targeted interventions to improve their clinical management. This study aimed to determine the prevalence of poor gout control and its associated demographic and clinical factors among urbanized community-dwelling Asian patients.

Methods

This retrospective study was based on data extracted from the electronic medical records of 8 public primary care clinics in Singapore. Patients with a diagnostic code of gout who had 2 or more visits between 1st January 2018 and 31st December 2019 were included in the analysis. Data extracted included: demographics, anthropological measurements, comorbidities, serum uric acid levels and medication prescription. A patient is defined to have poor gout control if they suffer two or more acute gout attacks within a year. Chi-Squared test was used for categorical parameters. For continuous variables, univariate logistic regression analysis was first performed. Significant factors (p ≤ 0.1) were then included in the logistics regression model to account for confounders.

Results

A total of 7,970 patients and 24,624 visits were included in the analysis. The prevalence of poorly controlled gout was 28.2% (n = 2,244/7,970); only 46.3% of them (n = 1,039/2,244) were prescribed allopurinol and 13.4% (n = 301/2,244) were taking doses ≥300 mg. Using logistic regression, factors associated with poor gout control were: male gender [adjusted OR (AOR) =1.66, p < 0.001], Malay ethnicity (AOR = 1.27, p = 0.007), congestive heart failure (AOR = 1.64, p = 0.037). Patients prescribed allopurinol (AOR = 1.52, p < 0.001), NSAIDs (AOR = 2.76, p < 0.001) and corticosteroids (AOR = 2.83, p < 0.001) were more likely to have poorly-controlled gout.

Conclusion

Nearly 30% of patients had poor gout. Interventions should focus on male and Malay patients and those with congestive cardiac failure.

Allopurinol for Secondary Prevention in Patients with Cardiovascular Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

The effects of allopurinol in patients with cardiovascular disease are not well defined; therefore, the latest evidence is summarized in this study.

METHODS

PubMed, Embase, Cochrane Library, and ClinicalTrials.gov databases were searched for randomized controlled trials (RCTs) of allopurinol in patients with cardiovascular disease published up to 11 February 2023. The primary outcome was cardiovascular death.

RESULTS

We combined the results of 21 RCTs that included 22,806 patients. Compared to placebo/usual care, allopurinol treatment was not associated with a significant reduction in cardiovascular death (RR 0.60; 95% CI 0.33-1.11) or all-cause death (RR 0.90; 95% CI 0.72-1.12). However, evidence from earlier trials and studies with small sample sizes indicated that allopurinol might confer a protective effect in decreasing cardiovascular death (RR 0.34; 95% CI 0.15-0.76) across patients undergoing coronary artery bypass grafting (CABG) or having acute coronary syndrome (ACS). In comparisons between allopurinol and febuxostat, we observed no difference in cardiovascular death (RR 0.92; 95% CI 0.69-1.24) or all-cause death (RR 1.02; 95% CI 0.75-1.38).

CONCLUSION

Allopurinol could not reduce cardiovascular (CV) death or major adverse CV outcomes significantly in patients with existing cardiovascular diseases. Given the limitations of the original studies, the potential advantages of allopurinol observed in patients undergoing CABG or presenting with ACS necessitate further confirmation through subsequent RCTs. In the comparisons between allopurinol and febuxostat, our analysis failed to uncover any marked superiority of allopurinol in reducing the risk of adverse cardiovascular incidents.

The association of allopurinol with persistent physical disability and frailty in a large community based older cohort

BACKGROUND

The protective effects of allopurinol on physical function in older adults are not well understood, despite its potential to improve functional gains and reduce sarcopenia. This study aims to determine the association between allopurinol, persistent physical disability, and frailty in older gout patients.

METHODS

This analysis used data from a randomized trial in an older cohort, ASPirin in Reducing Events in the Elderly (ASPREE). ASPREE recruited 19,114 participants aged ≥65 years without prior cardiovascular events, dementia, or independence-limiting physical disability at trial enrolment. This analysis examined the association of baseline and time-varying allopurinol use with persistent physical disability and new-onset frailty in participants with gout at baseline (self-report or use of any anti-gout medications). Frailty was measured using the Fried frailty phenotype (score ≥3/5) and a deficit accumulation frailty index (FI) (score >0.21/1.0). Multivariable Cox proportional-hazards models were used for main analyses.

RESULTS

This analysis included 1155 gout participants, with 630 taking allopurinol at baseline and 525 not. During a median follow-up of 5.7 years, 113 new allopurinol users were identified. Compared with nonusers, baseline allopurinol use was associated with a significant risk reduction of persistent physical disability (Adjusted HR 0.46, 95% CI 0.23-0.92, p = 0.03). The strength of the association was modestly attenuated in the time-varying analysis (Adjusted HR 0.56, 0.29-1.08, p = 0.08). No significant associations with frailty measures were observed for either baseline allopurinol use (Fried frailty: Adjusted HR 0.83, 0.62-1.12; FI: Adjusted HR 0.96, 0.74-1.24) or time-varying allopurinol use (Fried frailty: Adjusted HR 0.92, 0.69-1.24; FI: Adjusted HR 1.02, 0.78-1.33).

CONCLUSIONS

Allopurinol use in older adults with gout is associated with a reduced risk of persistent physical disability but not associated with risk of frailty.

Analysis of appropriate duration of colchicine prophylaxis to maximize the persistence of xanthine oxidase inhibitors as the first-line urate-lowering therapy in patients with gout using the Korean Health Insurance Review and Assessment Service database

INTRODUCTION

We investigated the appropriate duration of colchicine prophylaxis to maximize the persistence of xanthine oxidase inhibitors (XOIs) as first-line urate-lowering therapy (ULT) in patients with gout. This was a nationwide population-based retrospective cohort study using the Korean Health Insurance Review and Assessment database.

METHODS

Patients with gout aged ≥20 years who were newly initiated on XOIs, such as allopurinol or febuxostat, from July 2015 to June 2017 and received these medications for ≥6 months were analyzed and followed up until June 2019. Persistence of XOIs was compared according to the 6-month duration of colchicine prophylaxis. For additional subgroup analysis, we also compared the persistence of XOIs according to the 3-month duration of colchicine prophylaxis.

RESULTS

This study included 43 926 patients. The frequencies of patients with gout receiving colchicine prophylaxis for ≥6 months and ≥3 months were 6.3% and 7.6%, respectively. Allopurinol (65.2%) was prescribed more frequently than febuxostat (34.8%). During the study period, 23 475 patients (53.4%) stopped using XOIs. Colchicine prophylaxis for ≥6 months did not significantly reduce the risk of XOI discontinuation in multivariable Cox regression models. Colchicine prophylaxis for ≥3 months was significantly associated with a lower risk of non-persistence to XOIs after adjusting for confounding factors (hazard ratio = 0.95, p = .041).

CONCLUSION

Our data suggest that at least 3 months of colchicine prophylaxis may be more appropriate than at least 6 months in terms of maximizing the persistence of XOIs in patients with gout.

Allopurinol and oxypurinol differ in their strength and mechanisms of inhibition of xanthine oxidoreductase

Xanthine oxidoreductase is a metalloenzyme that catalyzes the final steps in purine metabolism by converting hypoxanthine to xanthine and then uric acid. Allopurinol, an analog of hypoxanthine, is widely used as an antigout drug, as xanthine oxidoreductase-mediated metabolism of allopurinol to oxypurinol leads to oxypurinol rotation in the enzyme active site and reduction of the molybdenum Mo(VI) active center to Mo(IV), inhibiting subsequent urate production. However, when oxypurinol is administered directly to a mouse model of hyperuricemia, it yields a weaker urate-lowering effect than allopurinol. To better understand its mechanism of inhibition and inform patient dosing strategies, we performed kinetic and structural analyses of the inhibitory activity of oxypurinol. Our results demonstrated that oxypurinol was less effective than allopurinol both in vivo and in vitro. We show that upon reoxidation to Mo(VI), oxypurinol binding is greatly weakened, and reduction by xanthine, hypoxanthine, or allopurinol is required for reformation of the inhibitor-enzyme complex. In addition, we show oxypurinol only weakly inhibits the conversion of hypoxanthine to xanthine and is therefore unlikely to affect the feedback inhibition of de novo purine synthesis. Furthermore, we observed weak allosteric inhibition of purine nucleoside phosphorylase by oxypurinol which has potentially adverse effects for patients. Considering these results, we propose the single-dose method currently used to treat hyperuricemia can result in unnecessarily high levels of allopurinol. While the short half-life of allopurinol in blood suggests that oxypurinol is responsible for enzyme inhibition, we anticipate multiple, smaller doses of allopurinol would reduce the total allopurinol patient load.

Hyperuricaemia Does Not Interfere with Aortopathy in a Murine Model of Marfan Syndrome

Redox stress is involved in the aortic aneurysm pathogenesis in Marfan syndrome (MFS). We recently reported that allopurinol, a xanthine oxidoreductase inhibitor, blocked aortopathy in a MFS mouse model acting as an antioxidant without altering uric acid (UA) plasma levels. Hyperuricaemia is ambiguously associated with cardiovascular injuries as UA, having antioxidant or pro-oxidant properties depending on the concentration and accumulation site. We aimed to evaluate whether hyperuricaemia causes harm or relief in MFS aortopathy pathogenesis. Two-month-old male wild-type (WT) and MFS mice (Fbn1^C1041G/+) were injected intraperitoneally for several weeks with potassium oxonate (PO), an inhibitor of uricase (an enzyme that catabolises UA to allantoin). Plasma UA and allantoin levels were measured via several techniques, aortic root diameter and cardiac parameters by ultrasonography, aortic wall structure by histopathology, and pNRF2 and 3-NT levels by immunofluorescence. PO induced a significant increase in UA in blood plasma both in WT and MFS mice, reaching a peak at three and four months of age but decaying at six months. Hyperuricaemic MFS mice showed no change in the characteristic aortic aneurysm progression or aortic wall disarray evidenced by large elastic laminae ruptures. There were no changes in cardiac parameters or the redox stress-induced nuclear translocation of pNRF2 in the aortic tunica media. Altogether, the results suggest that hyperuricaemia interferes neither with aortopathy nor cardiopathy in MFS mice.