Faculty Bibliography

Gout is a disease of hyperuricemia (HU) leading to monosodium urate crystal deposition in the joint, resulting in inflammation and joint damage. Recently, efforts have been made to characterize the intestinal microbiome of patients who suffer from HU and gout, and pre-clinical studies have evaluated the utility of prebiotics and probiotics in alleviating gout. Herein we review recent notable studies addressing these topics. In brief, the "gouty" microbiome is characterized by reduced diversity, an elevated Bacteroides: Firmicutes ratio, and reduced presence of Akkermansia and Bifidobacterium. In anserine models, supplementation with Lactobacillus probiotic strains appears to reduce serum urate (SU) and HU-induced inflammation. Murine models suggest that the chicory-derived prebiotic inulin may reduce SU, and oral supplementation with the anti-inflammatory short-chain fatty acid butyrate may lower SU by enhancing urate excretion and alleviate HU-induced tissue inflammation. Many of these studies are limited by modest numbers of participants and/or incompletely documented experimental controls, and, in the case of animal models, questionable reproducibility in humans. Many studies have been geographically limited. There remains a need for more information regarding the features of the "gouty" microbiome in wider populations, as well as for additional well-controlled probiotic and prebiotic studies in more physiologically relevant animal models prior to clinical trials.

INTRODUCTION/BACKGROUND:Patients receiving the standard prophylaxis dose of colchicine for gout flares are at increased risk for developing toxicity if there are pre-existing renal impairment or drug-drug interactions. Guidelines recommend exercising caution, deferring dose adjustment to the clinician's discretion. METHODS:Pharmacokinetic study data for colchicine oral solution in healthy subjects was used to build a pharmacokinetic model. Using the derived pharmacokinetic disposition parameters from the best fit model and the derived parameters of clearance in patients with renal impairment, simulation of colchicine plasma levels to target 0.5-3 ng/mL with colchicine oral solution was undertaken for various dose levels in different degrees of renal impairment. RESULTS:) would have excursions up to 10% and 36%, respectively, above the maximum tolerated level. Administering a lower dose such as 0.3 mg daily by splitting the conventional 0.6 mg tablet or by administering 0.6 mg once every-other-day (QOD) in moderate renal impairment would result in plasma colchicine levels in subtherapeutic range (< 0.5 ng/mL) for 20-70% of the dosing interval. CONCLUSION/CONCLUSIONS:Analysis of pharmacokinetic model data confirms that the majority of patients with renal impairment taking colchicine solid dosage formulations will be above or below therapeutic levels, exposing them to potential side effects. However, more precise dosing with colchicine oral solution of 0.48 mg (4 mL) or 0.5 mg tablet available in certain countries for moderate renal impairment and 0.3 mg (2.5 mL) for severe renal impairment are associated with optimal levels and safer for patients with renal impairment. No dosage adjustment is needed for patients with mild renal impairment.

OBJECTIVE:Controversy persists regarding the optimal management of gout in routine primary care. There is a lack of clarity on whether treating to a target serum urate (TTT-SU) versus treating to avoid symptoms (TTASx) is more effective. METHODS:We designed a randomized controlled comparative effectiveness trial aimed at patients in primary care who have known gout, have elevated SU levels, and had at least one flare in the previous 12 months. The trial was designed to be pragmatic and incorporated structured input from primary care physicians, rheumatologists, and patients. The TTASx strategy group will receive weeklong courses of typical therapies for gout flares, such as colchicine, naproxen, or an oral glucocorticoid. The TTT-SU strategy group will receive urate-lowering therapy (primarily allopurinol) with dose titration to maintain an SU level <6 mg/dL, colchicine (or naproxen) prophylaxis for the first six months of urate-lowering therapy, and access to the same flare therapies as the TTASx group. Two clinicians (nurses or physicians) per site will be trained in each strategy to manage the patients in each arm without contamination. Gout flares are the primary outcome and are assessed every two weeks by trained study staff masked to treatment assignment using a validated questionnaire. The secondary outcome is quality of life. Blood pressure control, kidney function, glycemic control, and coronary atherosclerosis are exploratory secondary outcomes. RESULTS:Several sites have started prescreening using automated search strategies in their patients' electronic health records. Of the first 1,381 patients found in primary care practices with a history of gout, 691 patients (50%) passed prescreening checks. These potentially eligible participants have a median age of 67 years, 85% are men, median SU levels are 7.2 mg/dL, and 18% are taking low dosages of allopurinol. These patients have been targeted for recruitment efforts that are underway now. CONCLUSION/CONCLUSIONS:This randomized controlled active comparator strategy trial will answer a key question in the treatment of patients with gout in primary care: the comparative effectiveness of TTT-SU versus TTASx in gout. Secondary and exploratory outcomes will add important information regarding the broader extra-articular and quality-of-life effects of lowering SU levels.

Gout, the most common inflammatory arthritis, affects as many as 5.1% of the adult population. Classically, gout is conceived as four sequential phenotypic states: 1) asymptomatic hyperuricemia 2) acute gout flare 3) inter-critical gout (gout between flares); and 4) tophaceous gout. However, these four states are paralleled by a fifth state, consisting of vascular involvement. The mechanisms and consequences of vascular gout are incompletely elucidated. In vitro and animal models indicate that soluble urate adversely affects vascular endothelium and smooth muscle. The recent discovery that soluble urate can be transported intracellularly to alter cell metabolism and epigenetics (trained innate immunity) suggests additional impacts of urate on leukocytes and endothelium. Once gout has progressed to flares, the vasculature is exposed to inflammatory mediators, both during flares and to a lesser but persistent extent inter-critically, suggesting additional mechanisms of gout's effect. We have reported that patients with gout have diminished endothelial function measured by brachial artery flow-mediated dilation. ACR gout guideline-concordant treatment improves endothelial function but is less effective in patients with cardiometabolic comorbidities. Moreover, treatment of gout patients with the anti-inflammatory colchicine and urate lowering therapy improves endothelial function and reduces the risk of both incident coronary artery disease (CAD), and MACE in patients with established CAD.

OBJECTIVE:This report evaluates rheumatologists' stated adherence to and agreement with the 2020 American College of Rheumatology (ACR) Guideline for the Management of Gout. METHODS:A 57-item questionnaire was administered to a sample of US rheumatologists. Stated adherence scores were based on several guideline recommendations reported to be followed by rheumatologists in practice, whereas stated agreement scores were based on whether respondents always followed the recommendations. RESULTS:≤ 0.05). Approximately 78% of rheumatologists claimed to follow the guideline for initiating urate-lowering therapy (ULT), and 89% were likely to prescribe allopurinol as a first-line ULT. Claimed adherence to recommendations for dosing was lower (febuxostat: 43%; allopurinol: 39%). Rheumatologists from academic settings were more likely to prescribe an interleukin-1 inhibitor for gout flares. CONCLUSION/CONCLUSIONS:The self-reported practice of the surveyed US rheumatologists was generally concordant with the 2020 ACR Guideline for the Management of Gout. However, there were gaps in guideline knowledge and stated adherence among rheumatologists, mainly concerning the dosing of treatment regimens.

RATIONALE & OBJECTIVE/OBJECTIVE:We conducted a prespecified examination of the efficacy and safety of allopurinol and febuxostat administered using a treat-to-target strategy in trial participants with chronic kidney disease (CKD). STUDY DESIGN/METHODS:Prespecified sub cohort analysis of a randomized controlled trial. SETTING/METHODS:at baseline. EXPOSURE/METHODS:Trial participants with CKD and gout and serum urate (sUA) concentration ≥6.8 mg/dL were randomized 1:1 to receive allopurinol or febuxostat. Urate lowering therapy (ULT) was titrated during weeks 0-24 to achieve a goal sUA of <6.0 mg/dl (<5.0 mg/dl with tophi) (Phase 1) and maintained during weeks 25-48 (Phase 2). Gout flare was assessed between weeks 49-72 (Phase 3). OUTCOME/RESULTS:Gout flare between weeks 49-72 (Phase 3) was the primary outcome. Secondary outcomes included sUA goal achievement and ULT dosing at end of Phase 2, and serious adverse events (SAEs). ANALYTICAL APPROACH/METHODS:Outcomes between treatment groups were compared using logistic regression models for binary outcomes, and Poisson regression for flare rates. Multivariable models were subsequently used, adjusting for factors identified to be imbalanced by treatment arm. RESULTS:351 of 940 participants (37.3%) had CKD; 277 were assessed for the primary outcome. Fewer patients randomized to allopurinol had a flare during phase 3 (32% vs 45%; p=0.02) despite similar attainment of sUA goal (79% vs. 81%; p=0.6) by the end of Phase 2. Acute kidney injury (AKI) was more common in participants with stage 3 CKD randomized to allopurinol compared to febuxostat. LIMITATIONS/CONCLUSIONS:Limited power to assess infrequent safety events, largely male, older population. CONCLUSIONS:Allopurinol and febuxostat are similarly efficacious and well-tolerated in the treatment of gout in people with CKD when used in a treat-to-target regimen.

Registration URL: https://clinicaltrials.gov. Unique identifier: NCT02594111.

INTRODUCTION/BACKGROUND:Patients with chronic refractory gout face a considerable burden of disease due to unexpected flares characterized by severe and debilitating pain, which can lead to chronic pain and joint damage. This study aimed to understand the symptoms and impacts of chronic refractory gout on health-related quality of life (HRQoL). METHODS:A targeted literature review was conducted to identify and review key articles describing the symptoms and impacts of gout, and articles examining the psychometric performance of the Medical Outcomes Survey Short Form-36 (SF-36) and Health Assessment Questionnaire-Disability Index (HAQ-DI) in gout. Qualitative interviews were conducted with 20 participants with chronic refractory gout. The results were used to develop the conceptual model and determine the appropriateness of the SF-36 and HAQ-DI in evaluating HRQoL in this population. RESULTS:Most frequently reported symptoms included bodily pain (n = 18, 90.0%), joint swelling (n = 18, 90.0%), joint tenderness (n = 18, 90.0%), and joint pain (n = 16, 80.0%). Most frequently reported impacts were difficulties climbing a flight (n = 20, 100.0%) or several flights of stairs (n = 20, 100.0%), climbing five steps (n = 19, 95.0%), completing chores (n = 19, 95.0%), and running errands and shopping (n = 19, 95.0%). All assessed items from SF-36 and HAQ-DI were reported by ≥ 25% (n = 5) of participants and mapped sufficiently to concepts elicited by participants. CONCLUSIONS:Patients with chronic refractory gout report symptoms and impacts that are highly bothersome and burdensome to everyday life. Items included in the HAQ-DI and SF-36 mapped directly to these symptoms and impacts and are relevant to understand the burden of disease of chronic refractory gout.

OBJECTIVE:Initiating urate-lowering therapy (ULT) in gout can precipitate arthritis flares. There have been limited comparisons of flare risk during the initiation and escalation of allopurinol and febuxostat, administered as a treat-to-target strategy with optimal anti-inflammatory prophylaxis. METHODS:This was a post-hoc analysis of a 72-week randomized, double-blind, placebo-controlled, noninferiority trial comparing the efficacy of allopurinol and febuxostat. For this analysis, the occurrence of flares was examined during weeks 0 to 24 when ULT was initiated and titrated to a serum urate (sUA) goal of less than 6 mg/dl (<5 mg/dl if tophi). Flares were assessed at regular intervals through structured participant interviews. Predictors of flare, including treatment assignment, were examined using multivariable Cox proportional hazards regression. RESULTS:Study participants (n = 940) were predominantly male (98.4%) and had a mean age of 62.1 years with approximately equal proportions receiving allopurinol or febuxostat. Mean baseline sUA was 8.5 mg/dl and all participants received anti-inflammatory prophylaxis (90% colchicine). In a multivariable model, there were no significant associations of ULT treatment (hazard ratio [HR] 1.17; febuxostat vs allopurinol), ULT-dose escalation (HR 1.18 vs no escalation), prophylaxis type, or individual comorbidity with flare and no evidence of ULT-dose escalation interaction. Factors independently associated with flare risk during ULT initiation/escalation included younger age, higher baseline sUA, and absence of tophi. CONCLUSION/CONCLUSIONS:These results demonstrate that gout flare risk during the initiation and titration of allopurinol is similar to febuxostat when these agents are administered according to a treat-to-target strategy using gradual ULT-dose titration and best practice gout flare prophylaxis.