Reduced creatinine clearance is associated with early development of subcutaneous tophi in people with gout

Gout comorbidities: results from the Korean National Health and Nutrition Examination Survey

OBJECTIVES

Gout is associated with several comorbidities. This study aimed to evaluate the prevalence of comorbidities in the Korean adult population with gout and investigated the association of gout with these comorbidities.

METHODS

Data from 15,935 (weighted n = 39,049,167) participants aged 19 years and older in the Korean National Health and Nutrition Examination Survey from 2019 to 2021 were used for analysis. Weighted prevalence and odds ratios (OR) of comorbidities in individuals with gout were compared to a non-gout population.

RESULTS

The weighted prevalence of gout was 2.1% (weighted n = 808,778). Among individuals with gout, 66.5% had metabolic syndrome, 54.9% had hypertension, 41.2% had hypercholesterolemia, 19.1% had diabetes, 13.5% had chronic kidney disease (CKD), 4.1% had myocardial infarction or angina, 3.8% had stroke, and 2.8% had rheumatoid arthritis (RA). After adjusting for socioeconomic and lifestyle characteristics, gout was independently associated with the increased prevalence of metabolic syndrome (male OR = 2.0, 95% confidence interval (CI): 1.5-2.8; female OR = 3.7, 95% CI: 1.5-9.2), hypercholesterolemia (male OR = 1.9, 95% CI: 1.4-2.5; female OR = 3.1, 95% CI: 1.3-7.5), CKD (male OR = 4.5, 95% CI: 2.7-7.3; female OR = 11.5, 95% CI: 4.1-32.1), and RA (male OR = 2.8, 95% CI: 1.1-7.1; female OR = 3.1, 95% CI: 1.1-8.7) compared to the non-gout population.

CONCLUSIONS

Gout was associated with several comorbidities, including RA, in both males and females. These results suggest that the prevention and treatment of comorbidities at the individual level, carried out by clinicians, and knowledge of these comorbidities would help guide health policies for the Korean population.

Gout Affecting the Nail Unit: Report of Two Cases and Literature Review

Background

Gout is a depositional, inflammatory disorder that is rarely reported to affect the nail unit. Cases of gout involving the nail unit are likely under-recognized and therefore underreported. We present two cases of tophaceous gout affecting the nail unit and a literature review of the various presentations.

Summary

Five cases of gout were identified to affect the nail unit. In all cases, these presented as white hyperkeratotic papulonodules with associated nail dystrophy. Chalky discharge was seen in three of the five cases. Nine cases were identified to have demonstrated pseudocarcinomatous changes that histopathologically mimic squamous cell carcinoma (SCC). Literature review highlights a range of findings including subclinical deposits of uric acid in the nail, onychoschizia, onychorrhexis, and Beau's line.

Key Messages

Physicians should be aware of the subtle and nonspecific clinical findings of gout, which may be easily misconstrued for other pathological entities.

Association between specific ultrasound features of joints and impaired kidney function among gout patients

OBJECTIVE

To investigate the relationship between the specific ultrasonic manifestations of lower limb joints and impaired kidney function in gouty arthritis.

METHODS

In this cross-sectional study, 408 patients with gouty arthritis were divided into two groups based on the status of renal function: normal group (n = 240) and renal impairment (n = 168) group. All patients underwent ultrasound examination of the bilateral knee, ankle, and first metatarsophalangeal joints to detect ultrasound features of double-contour sign (DC) and tophus. Multiple logistic regression analysis was conducted to assess the association between kidney dysfunction and ultrasound features. A number of potential clinical confounders were adjusted in the model.

RESULTS

Univariable conditional logistic regression produces several significant risk factors of impaired kidney function which were the highest and current lever of serum urate acid, course of disease, frequency of attack, hyperlipidemia, hypertension, diabetes, coronary heart disease, presence of multiple tophus, and DC (P < 0.05). After correcting the course of disease and other risk factors, tophus was still an independent risk factor of impaired kidney function and the multivariable adjusted odds ratios (95% CI) was 1.789 (1.005-3.185, P = 0.05), however, the association was not significant in DC (OR = 1.098, 95% CI: 0.668-1.803, P = 0.71).

CONCLUSION

The ultrasound feature of tophus was associated with kidney dysfunction in patients with gout, independent of clinical risk factors, which may be helpful in guiding clinical practice.

Management of Patients with Gout and Kidney Disease: A Review of Available Therapies and Common Missteps

Gout, a common form of inflammatory arthritis, is characterized by deposition of monosodium urate crystals in articular and periarticular tissues. Repeated flares of gout cause joint damage as well as significant health care utilization and decreased quality of life. Patients with CKD have a higher prevalence of gout. Treating Patients with CKD and gout is challenging because of the lack of quality data to guide management in this specific population. This often leads to suboptimal treatment of patients with gout and impaired renal function because concerns regarding the efficacy and safety of available gout therapies in this population often result in significant interphysician variability in treatment regimens and dosages. Acute gout flares are treated with various agents, including nonsteroidal anti-inflammatory drugs, colchicine, glucocorticoids, and-more recently-IL-1 inhibitors. These medications can also be used as prophylaxis if urate-lowering therapy (ULT) is initiated. While these drugs can be used in patients with gout and CKD, there are often factors that complicate treatment, such as the numerous medication interactions involving colchicine and the effect of glucocorticoids on common comorbidities, such as diabetes and hypertension. ULT is recommended to treat recurrent flares, tophaceous deposits, and patients with moderate-to-severe CKD with a serum urate goal of <6 mg/dl recommended to prevent flares. While many misconceptions exist around the risks of using urate-lowering agents in patients with CKD, there is some evidence that these medications can be used safely in Patients with renal impairment. Additional questions exist as to whether gout treatment is indicated for Patients on RRT. Furthermore, there are conflicting data on whether ULT can affect renal function and cardiovascular disease in patients. All of these factors contribute to the unique challenges physicians face when treating patients with gout and CKD.

Associated Factors of Tophaceous Gout: A Study Involving 20 Primary Care Clinics in an Urbanized State in Malaysia

Objectives

Gout is a treatable disease. A complication of untreated or poorly-controlled gout is tophi formation. We conducted this study to investigate the associated factors of tophaceous gout among patients who attended 20 primary care clinics in Selangor, an urbanized state in Malaysia.

Methods

We conducted a cross-sectional study from July to October 2019 that included all patients with gout who attended the clinics. Data on clinical demographics and laboratory results were collected. Comparison between tophaceous and non-tophaceous groups was performed using descriptive analysis.

Results

A total of 421 patients with gout were involved in this study, 83 (19.7%) patients had visible tophi and were categorized into the tophaceous group, while the other 338 (80.3%) patients were categorized into the non-tophaceous group. The majority of patients were male with a mean age of 57.6±12.8 years. Three factors found to be significantly associated with tophaceous gout were age at symptom onset [tophaceous (45.6±13.3 years) vs. non-tophaceous (49.7±13.9 years), p = 0.026], mean disease duration of gout [tophaceous (105.2±92.6 months) vs. non-tophaceous (77.6±88.6 months), p = 0.013], and baseline serum uric acid level [tophaceous (622.3±129.1 µmol/L) vs. non-tophaceous (582.6±102.3 µmol/L), p = 0.021].

Conclusions

Tophaceous gout is associated with longer disease duration, higher baseline serum uric acid level, and younger age at symptoms onset. Hence, early initiation of urate-lowering therapy with a treat-to-target approach is crucial to prevent tophi formation.

Uric acid en route to gout

Gout and hyperuricemia (HU) have generated immense attention due to increased prevalence. Gout is a multifactorial metabolic and inflammatory disease that occurs when increased uric acid (UA) induce HU resulting in monosodium urate (MSU) crystal deposition in joints. However, gout pathogenesis does not always involve these events and HU does not always cause a gout flare. Treatment with UA-lowering therapeutics may not prevent or reduce the incidence of gout flare or gout-associated comorbidities. UA exhibits both pro- and anti-inflammation functions in gout pathogenesis. HU and gout share mechanistic and metabolic connections at a systematic level, as shown by studies on associated comorbidities. Recent studies on the interplay between UA, HU, MSU and gout as well as the development of HU and gout in association with metabolic syndromes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular, renal and cerebrovascular diseases are discussed. This review examines current and potential therapeutic regimens and illuminates the journey from disrupted UA to gout.

The Hong Kong Society of Rheumatology consensus recommendations for the management of gout

Gout is one of the most common noncommunicable diseases in Hong Kong. Although effective treatment options are readily available, the management of gout in Hong Kong remains suboptimal. Like other countries, the treatment goal in Hong Kong usually focuses on relieving symptoms of gout but not treating the serum urate level to target. As a result, patients with gout continue to suffer from the debilitating arthritis, as well as the renal, metabolic, and cardiovascular complications associated with gout. The Hong Kong Society of Rheumatology spearheaded the development of these consensus recommendations through a Delphi exercise that involved rheumatologists, primary care physicians, and other specialists in Hong Kong. Recommendations on acute gout management, gout prophylaxis, treatment of hyperuricemia and its precautions, co-administration of non-gout medications with urate-lowering therapy, and lifestyle advice have been included. This paper serves as a reference guide to all healthcare providers who see patients who are at risk and are known to have this chronic but treatable condition.

Therapeutics in rheumatology and the kidney

The field of rheumatology has advanced significantly in recent years to provide rheumatologists with an extensive array of medications to combat rheumatic joint conditions. In contrast to an older era, when NSAIDs and other nephrotoxic agents were the mainstay of treatment, modern DMARDs vary considerably in their nephrotoxic potential and their use is not always precluded in populations with pre-existing chronic kidney disease (CKD). This review will explore in detail the safety and efficacy profiles of medications used to treat rheumatologic disease, specifically in the setting of CKD. Specifically, we discuss both traditional agents used, i.e. NSAIDs, CSs and conventional synthetic DMARDs, as well as novel biologic DMARDs and targeted synthetic DMARDs. Anti-gout prescribing in CKD is also reviewed. We aim to provide practical guidance to rheumatologists, nephrologists and general physicians when prescribing these medications in the setting of CKD.

Febuxostat Therapy for Patients with Gout and Stage 2-4 CKD: a Retrospective Study

Introduction

The aim of this study is to explore the efficacy and renal safety of febuxostat in gout and stage 2–4 chronic kidney disease (CKD) and factors that correlated with target serum urate (SU).

Methods

A single-center retrospective study including male patients with gout and CKD was conducted. SU, the rate of SU < 360 µmol/L (RAT), and renal safety were analyzed in subjects who received febuxostat over 44 weeks. Factors that correlated with target SU were also explored.

Results

Between January 2017 and March 2021, 102 patients (stage 2 CKD: n = 27; stage 3 CKD: n = 70; stage 4 CKD: n = 5) were enrolled. The SU level reduced significantly over 44 weeks (600.76 ± 95.42 versus 405.52 ± 111.93 µmol/L; P < 0.05), and RAT increased to 39.20%. The overall estimated glomerular filtration rate (eGFR) level improved over 44 weeks (52.05 ± 11.68 versus 55.46 ± 14.49 mL/min/1.73 cm², P < 0.05). An obvious improvement of eGFR was observed in stage 3 CKD, in patients with ≤ 1 risk factor (hypertension, diabetic mellitus, hyperlipidemia, or usage of non-steroidal anti-inflammatory drugs), and in patients with terminal SU < 360 µmol/L (P < 0.05). Logistic regression analysis indicated that baseline SU level and body weight were correlated with RAT. Further analysis revealed that patients with SU < 600 μmol/L and body weight ≤ 70 kg reached higher RAT (56.7%).

Conclusions

Febuxostat demonstrated efficacy and renal safety in patients with gout and CKD in clinical practice. Achieving the target SU could obviously improve renal function. Baseline SU level and body weight could affect the achievement of target SU.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40744-022-00480-7.

Mini Review: Reappraisal of Uric Acid in Chronic Kidney Disease

Hyperuricemia predicts the development of chronic kidney disease (CKD) and metabolic complications, but whether it has a causal role has been controversial. This is especially true given the 2 recently conducted randomized controlled trials that failed to show a benefit of lowering uric acid in type 1 diabetes-associated CKD and subjects with stage 3-4 CKD. While these studies suggest that use of urate-lowering drugs in unselected patients is unlikely to slow the progression of CKD, there are subsets of subjects with CKD where reducing uric acid synthesis may be beneficial. This may be the case in patients with gout, hyperuricemia (especially associated with increased production), and urate crystalluria. Here, we discuss the evidence and propose that future clinical trials targeting these specific subgroups should be performed.

Management of gout in chronic kidney disease: a G-CAN Consensus Statement on the research priorities

Gout and chronic kidney disease (CKD) frequently coexist, but quality evidence to guide gout management in people with CKD is lacking. Use of urate-lowering therapy (ULT) in the context of advanced CKD varies greatly, and professional bodies have issued conflicting recommendations regarding the treatment of gout in people with concomitant CKD. As a result, confusion exists among medical professionals about the appropriate management of people with gout and CKD. This Consensus Statement from the Gout, Hyperuricemia and Crystal-Associated Disease Network (G-CAN) discusses the evidence and/or lack thereof for the management of gout in people with CKD and identifies key areas for research to address the challenges faced in the management of gout and CKD. These discussions, which address areas for research both in general as well as related to specific medications used to treat gout flares or as ULT, are supported by separately published G-CAN systematic literature reviews. This Consensus Statement is not intended as a guideline for the management of gout in CKD; rather, it analyses the available literature on the safety and efficacy of drugs used in gout management to identify important gaps in knowledge and associated areas for research.

Prevalence of Musculoskeletal Manifestations in Adult Kidney Transplant's Recipients: A Systematic Review

Background and Objectives: The musculoskeletal (MSK) manifestations in the kidney transplant recipient (KTxR) could lead to decreased quality of life and increased morbidity and mortality. However, the prevalence of these MSK manifestations is still not well-recognized. This review aimed to investigate the prevalence and outcomes of MSK manifestations in KTxR in the last two decades. Materials and Methods: Research was performed in EBSCO, EMBASE, CINAHL, PubMed/MEDLINE, Cochrane, Google Scholar, PsycINFO, Scopus, Science Direct, and Web of Science electronic databases were searched during the years 2000–2020. Results: The PRISMA flow diagram revealed the search procedure and that 502 articles were retrieved from the initial search and a total of 26 articles were included for the final report in this review. Twelve studies reported bone loss, seven studies reported a bone pain syndrome (BPS) or cyclosporine-induced pain syndrome (CIPS), and seven studies reported hyperuricemia (HU) and gout. The prevalence of MSK manifestations in this review reported as follow: BPS/CIPS ranged from 0.82% to 20.7%, while bone loss ranged from 14% to 88%, and the prevalence of gout reported in three studies as 7.6%, 8.0%, and 22.37%, while HU ranged from 38% to 44.2%. Conclusions: The post-transplantation period is associated with profound MSK abnormalities of mineral metabolism and bone loss mainly caused by corticosteroid therapy, which confer an increased fracture risk. Cyclosporine (CyA) and tacrolimus were responsible for CIPS, while HU or gout was attributable to CyA. Late diagnosis or treatment of post-transplant bone disease is associated with lower quality of life among recipients

Presence of tophi is associated with a rapid decline in the renal function in patients with gout

We aimed to compare clinical characteristics of patients with and without tophi at the time of the diagnosis of gout and investigate the association of tophi and renal function in gout patients. The patients who were first diagnosed with gout at the Kangwon National University Hospital were retrospectively studied. Patients were divided into 2 groups according to the presence of tophi at the diagnosis. We compared clinical characteristics and the progression of renal dysfunction between the two groups. Of 276 patients, 66 (25.5%) initially presented with tophi. Tophi group was older, had a longer symptom duration, and a higher prevalence of multiple joint involvement than those without tophi. In multivariate logistic regression analysis, prolonged symptom duration and multiple joint involvement were significantly associated with increased risk of formation of tophi. The decline in the eGFR was more prominent in patients with tophi than in those without (- 4.8 ± 14.5 vs. - 0.7 ± 11.9 ml/min/1.73 m²/year, respectively; P = 0.039). The presence of tophi was significantly associated with a rapid decline in the eGFR (β = - 0.136; P = 0.042). In conclusion, the presence of tophi was associated with a rapid declining renal function. Therefore, an early diagnosis and closely monitoring of renal function might be important in gout patients with tophi.

The Management of Gout in Renal Disease

Gout, a debilitating inflammatory arthritis, currently affects more than 9 million Americans. Hyperuricemia, the laboratory abnormality associated with the development of gout, also occurs in a significant number of patients with chronic kidney disease (CKD), a condition that affects approximately 14% of the US population. Several recent studies have attempted to provide a definitive link between the presence of hyperuricemia and progression of CKD; however, the treatment of asymptomatic hyperuricemia in CKD is not supported by recent randomized controlled trials. The pharmacology of acute gout flares and urate lowering is complicated in patients who also have evidence of CKD, primarily because of an increased risk of medication toxicity. Recipients of kidney transplants are particularly at risk of debilitating gout and medication toxicity. We review the available data linking CKD, gout, and hyperuricemia, providing practice guidelines on managing gout in CKD patients and kidney transplant recipients. We advocate for much greater involvement of nephrologists in the management of gout in renal patients.

Pathophysiology of Gout

Multiple interacting checkpoints are involved in the pathophysiology of gout. Hyperuricemia is the key risk factor for gout and is considered a prerequisite for monosodium urate (MSU) crystal formation. Urate underexcretion through renal and gut mechanisms is the major mechanism for hyperuricemia in most people. Multiple genetic, environmental, and metabolic factors are associated with serum urate and alter urate transport or synthesis. Urate supersaturation is the most important factor for MSU crystal formation, and other factors such as temperature, pH, and connective tissue components also play a role. The nucleotide-binding oligomerization domain leucine-rich repeats and pyrin domain-containing protein 3 inflammasome plays a pivotal role in the inflammatory response to MSU crystals, and interleukin 1β is the key cytokine mediating the inflammatory cascade. Variations in the regulatory mechanisms of this inflammatory response may affect an individual's susceptibility to developing gout. Tophus formation is the cardinal feature of advanced gout, and both MSU crystals and the inflammatory tissue component of the tophus contribute to the development of structural joint damage owing to gout. In this article, we review the pathophysiologic mechanisms of hyperuricemia, MSU crystal formation and the associated inflammatory response, tophus formation, and structural joint damage in gout.

2020 American College of Rheumatology Guideline for the Management of Gout

OBJECTIVE

To provide guidance for the management of gout, including indications for and optimal use of urate-lowering therapy (ULT), treatment of gout flares, and lifestyle and other medication recommendations.

METHODS

Fifty-seven population, intervention, comparator, and outcomes questions were developed, followed by a systematic literature review, including network meta-analyses with ratings of the available evidence according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology, and patient input. A group consensus process was used to compose the final recommendations and grade their strength as strong or conditional.

RESULTS

Forty-two recommendations (including 16 strong recommendations) were generated. Strong recommendations included initiation of ULT for all patients with tophaceous gout, radiographic damage due to gout, or frequent gout flares; allopurinol as the preferred first-line ULT, including for those with moderate-to-severe chronic kidney disease (CKD; stage >3); using a low starting dose of allopurinol (≤100 mg/day, and lower in CKD) or febuxostat (<40 mg/day); and a treat-to-target management strategy with ULT dose titration guided by serial serum urate (SU) measurements, with an SU target of <6 mg/dl. When initiating ULT, concomitant antiinflammatory prophylaxis therapy for a duration of at least 3-6 months was strongly recommended. For management of gout flares, colchicine, nonsteroidal antiinflammatory drugs, or glucocorticoids (oral, intraarticular, or intramuscular) were strongly recommended.

CONCLUSION

Using GRADE methodology and informed by a consensus process based on evidence from the current literature and patient preferences, this guideline provides direction for clinicians and patients making decisions on the management of gout.

2020 American College of Rheumatology Guideline for the Management of Gout

OBJECTIVE

To provide guidance for the management of gout, including indications for and optimal use of urate-lowering therapy (ULT), treatment of gout flares, and lifestyle and other medication recommendations.

METHODS

Fifty-seven population, intervention, comparator, and outcomes questions were developed, followed by a systematic literature review, including network meta-analyses with ratings of the available evidence according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology, and patient input. A group consensus process was used to compose the final recommendations and grade their strength as strong or conditional.

RESULTS

Forty-two recommendations (including 16 strong recommendations) were generated. Strong recommendations included initiation of ULT for all patients with tophaceous gout, radiographic damage due to gout, or frequent gout flares; allopurinol as the preferred first-line ULT, including for those with moderate-to-severe chronic kidney disease (CKD; stage >3); using a low starting dose of allopurinol (≤100 mg/day, and lower in CKD) or febuxostat (<40 mg/day); and a treat-to-target management strategy with ULT dose titration guided by serial serum urate (SU) measurements, with an SU target of <6 mg/dl. When initiating ULT, concomitant antiinflammatory prophylaxis therapy for a duration of at least 3-6 months was strongly recommended. For management of gout flares, colchicine, nonsteroidal antiinflammatory drugs, or glucocorticoids (oral, intraarticular, or intramuscular) were strongly recommended.

CONCLUSION

Using GRADE methodology and informed by a consensus process based on evidence from the current literature and patient preferences, this guideline provides direction for clinicians and patients making decisions on the management of gout.

Risk factors of ultrasound-detected tophi in patients with gout

INTRODUCTION

Tophus is a characteristic manifestation of advanced gout, the clinical significance of which is often underestimated. This study aimed to compare the difference of clinical and ultrasound features between gout patients with and without ultrasound-detected tophus and identify risk factors associated with the presence of ultrasonographic tophus in gout patients.

MATERIALS AND METHODS

A total of 85 gout patients were divided into tophaceous (n = 54) and non-tophaceous group (n = 31) according to the presence of ultrasound-detected tophus. All patients underwent ultrasound examination of the bilateral knee, ankle, and first metatarsophalangeal joint (MTP1). Clinical information and ultrasound findings were compared between the groups. A multivariate logistic regression analysis to determine possible risk factors is associated with the number of ultrasound-detected tophaceous joints.

RESULTS

Older age, longer gout duration, higher gout flare frequency, lower estimated glomerular filtration rate (eGFR), and higher prevalence of hypertension, hyperlipidemia, and ultrasound manifestations including double contour sign (DCS) and erosion were observed in tophaceous patients from the univariate analysis. Multivariable logistic regression analysis showed that eGFR and disease duration were independently associated with the number of tophaceous joints. Lower eGFR and longer course duration were associated with a higher risk of tophi (B = -0.020, 0.141; P = 0.009, 0.010, respectively).

CONCLUSIONS

The main factors that may influence the formation of tophi are disease duration and eGFR.Key Points• Lower eGFR and longer course duration are independent risk factors of tophi formation in gout patients.• The incidence of ultrasound manifestations including double contour sign (DCS) and erosion in patients with tophi were higher than those without tophi.

Gouty Tophi Manifesting as a Pancreatic Foci

Gout is a common disorder of uric acid metabolism highly prevalent in our population. The majority of patients with gout present with acute monoarticular arthritis, but a significant proportion of patients also go on to develop chronic tophaceous gout. Musculoskeletal sites are the usual sites of tophus formation and, very rarely, tophi may form in a visceral organ. We present a case of pancreatic gout of which only 3 cases have been reported. Our case is unique and challenging, as it initially masqueraded as a pancreatic neoplasm creating many diagnostic dilemmas.

Clinical characteristics and risk factors of ulceration over tophi in patients with gout

OBJECTIVES

To describe clinical characteristics of ulceration over tophi in patients with gout and determine risk factors associated with ulceration.

METHODS

Patients presenting with tophi or ulceration(s) over tophi were prospectively recruited and their clinical characteristics were recorded. Comparison of clinical characteristics and risk factors for ulceration were analyzed between groups.

RESULTS

A total of 105 patients were enrolled. Thirty-three patients with ulcerations were older, with prolonged duration with gout and tophi, a higher rate of obesity, greater numbers of tophi, lower levels of glomerular filtration rate (GFR), and higher levels of serum creatinine, erythrocyte sedimentation rate and C-reactive protein. The mean duration of ulceration was 1.63 ± 2.32 months. The ulcerations were mainly located in the ankle (34.21%) and metatarsophalangeal joints (39.47%), with a mean size of 32.37 × 22.76 mm. The majority of ulcerations were categorized as stage I (42.4%) and stage II (51.5%). In univariate regression analysis, age, glucocorticoid overuse, gout duration, tophi duration, tophi number and GFR were associated with ulceration. In the multivariable model, significant differences were demonstrated in glucocorticoid overuse, tophi duration, tophi number.

CONCLUSIONS

Gout patients with ulceration(s) over tophi present several different aspects of clinical characteristics compared with those without ulceration. The ulcerations are most commonly seen in feet and they are mainly categorized as stages I and II. Glucocorticoid overuse, prolonged duration with tophi and greater numbers of tophi are risk factors for ulceration over tophi.

Characterization of patients with chronic refractory gout who do and do not have clinically apparent tophi and their response to pegloticase

OBJECTIVES

To determine the characteristics and response to pegloticase of patients with chronic refractory gout with and without clinically apparent tophi.

METHODS

Results from two randomized controlled trials of pegloticase in patients with chronic refractory gout with clinically apparent tophi or without tophi were used to assess baseline and on-treatment between-group differences.

RESULTS

Patients with tophi were significantly older than those without tophi, had a significantly longer duration of disease, higher numbers of tender and swollen joints, higher Patient Global Assessment scores and Health Assessment Questionnaire-Disability Index scores, and lower Arthritis-Specific Health Index scores. Patients with tophaceous gout also had significantly lower scores for physical functioning, role physical, social functioning, and the physical component summary scores of the Short Form 36 vs patients without tophi. In addition, subjects with clinically apparent tophi had a significantly lower mean estimated glomerular filtration rate. Pegloticase treatment of tophaceous patients caused significant reductions in serum urate, flares, Patient Global Assessment, tender joints, swollen joints, Health Assessment Questionnaire-Disability Index, visual analogue scale pain and Short Form 36 Bodily Pain, whereas patients without tophi had significant improvement in serum urate, flares, Patient Global Assessment, tender joints, and Short Form 36 Bodily Pain, but not swollen joints, Health Assessment Questionnaire-Disability Index functional score or pain visual analogue scale. Treatment with pegloticase had no effect on estimated glomerular filtration rate despite significant lowering of the urinary uric acid: creatinine ratio.

CONCLUSION

Patients with chronic refractory gout and clinically apparent tophi have more severe disease as well as reduced renal function. Both groups experienced significant clinical benefit with pegloticase treatment, although no change in renal function was noted.

Clinical characteristics of infectious ulceration over tophi in patients with gout

Objective The aim of this study was to investigate the clinical characteristics of infectious ulceration over tophi in patients with gout. Methods Participants were recruited from the First Affiliated Hospital of Wenzhou Medical University. The clinical characteristics of the patients and wound characteristics were recorded. Results Of the 38 enrolled patients, 18 were found to have infectious ulceration over tophi. Staphylococcus aureus was the most common pathogen and was identified in nine patients. Patients with infection were significantly older (69.6 vs. 60.1 years) and had a worse quality of life than those without infection. Patients with infection also had a significantly longer ulcer duration (125.6 vs. 54.2 days), larger ulcer size (2.47 vs. 1.99 cm²), a higher rate of tissue necrosis in the ulcer bed (55.6% vs. 20.0%), a lower rate of callus at the edge (27.8% vs. 70.0%), and a higher moisture level than did patients without infection. Additionally, patients with infection had significantly delayed wound healing (35.3 vs. 20.3 days) compared with patients without infection. Conclusions Older patients with a long ulcer duration and larger ulcer size are more susceptible to infection. Infection can lower patients' quality of life and delay wound healing.

Clinical characteristics associated with subcutaneous tophi formation in Chinese gout patients: a retrospective study

The objective of this study is to analyze clinical characteristics associated with the formation of subcutaneous tophi among Chinese gout patients. It was a retrospective outpatient cohort study. Five thousand six hundred ninety-three gout patients treated at the Affiliated Hospital of Qingdao University from March 2011 to February 2016 were included and divided into the tophus group and non-tophus group according to the presence of megascopic tophus. Relevant clinical information and biochemical parameters were analyzed to identify potential risk factors for the incidence of subcutaneous tophi. There are significant difference (P < 0.05) between the tophus and non-tophus groups in gender, family history, exercise, incidence of obesity, hypertension, renal dysfunction, kidney stone, coronary heart disease, and upper limb joint involvement. Between the two groups, significant difference (P < 0.01) was detected in the onset age (43.80 ± 13.82 years vs. 45.40 ± 13.77 years), duration of disease (10.28 ± 7.54 years vs. 5.11 ± 6.06 years), number of joint involved (3.11 ± 2.15 vs. 1.81 ± 1.35), systolic pressure (138.53 ± 19.46 mmHg vs. 133.87 ± 17.93 mmHg), diastolic pressure (89.55 ± 12.73 mmHg vs. 87.48 ± 11.77 mmHg), serum uric acid (487.15 ± 120.13 μmol/L vs. 458.89 ± 119.04 μmol/L), creatinine (93.87 ± 54.19 μmol/L vs. 85.51 ± 37.71 μmol/L), and creatinine clearance rate (Ccr) (93.05 ± 48.7 mL/min vs. 106.61 ± 51.76 mL/min). Logistic regression analysis suggests that duration of disease, number of joints involved, involvement of upper limb joints, kidney stones, diastolic pressure, and serum uric acid are associated with the subcutaneous tophi formation, while exercise and obesity are protective factors. The present study has identified several clinical parameters (such as duration of disease, involvement of upper limb joints, involved joints, kidney stone, hypertension) as risk factors for the incidence of subcutaneous tophi, which provides insights into the treatment and prevention of tophus.

Risk factors for ulceration over tophi in patients with gout

Ulceration over tophi in patients with gout usually causes a number of clinical problems. The aim of this study was to investigate the risk factors for ulceration of tophi in patients with gout. Patients with gout who had tophi with or without ulceration were prospectively recruited and underwent a comprehensive clinical assessment. Clinical factors independently associated with the presence of ulceration were analysed using logistic regression models. Of the 113 participants, 18 (13·7%) had clinically apparent ulceration over tophi. In univariate analysis, ulceration over tophi correlated with age, tophus duration, size, location and lack of protective sensation. In logistic regression analysis, age, tophus size and lack of protective sensation were associated with ulceration over tophi. These findings indicate that old age, large tophus size and lack of protective sensation were independent risk factors for ulceration over tophi.

Asymptomatic Papules and Subcutaneous Nodules as First Sign of Gout

The authors describe a case report characterised by asymptomatic papules and non-tender subcutaneous nodules as the isolated manifestations of gout.

Predictors of Mortality in People with Recent-onset Gout: A Prospective Observational Study

OBJECTIVE

To determine mortality rates and predictors of death at baseline in people with a recent onset of gout.

METHODS

People with gout disease duration < 10 years were recruited from primary and secondary care settings. Comprehensive clinical assessment was completed at baseline. Participants were prospectively followed for at least 1 year. Information about death was systematically collected from primary and secondary health records. Standardized mortality ratios (SMR) were calculated and risk factors for mortality were analyzed using Cox proportional hazard regression models.

RESULTS

The mean (SD) followup duration was 5.1 (1.6) years (a total 1511 patient-yrs accrued). Of the 295 participants, 43 (14.6%) had died at the time of censorship (SMR 1.96, 95% CI 1.44-2.62). In the reduced Cox proportional hazards model, these factors were independently associated with an increased risk of death from all causes: older age (70-80 yrs: HR 9.96, 95% CI 3.30-30.03; 80-91 yrs: HR 9.39, 95% CI 2.68-32.89), Māori or Pacific ethnicity (HR 2.48, 95% CI 1.17-5.29), loop diuretic use (HR 3.99, 95% CI 2.15-7.40), serum creatinine (per 10 µmol/l change; HR 1.04, 95% CI 1.00-1.07), and the presence of subcutaneous tophi (HR 2.85, 95% CI 1.49-5.44). The presence of subcutaneous tophi was the only baseline variable independently associated with both cardiovascular (CV) cause of death (HR 3.13, 95% CI 1.38-7.10) and non-CV cause of death (HR 3.48, 95% CI 1.25-9.63).

CONCLUSION

People with gout disease duration < 10 years have an increased risk of death. The presence of subcutaneous tophi at baseline is an independent predictor of mortality, from both CV and non-CV causes.

Evaluation of cardiovascular risk in stages of gout by a complex multimodal ultrasonography

The aim of our work was to assess ultrasound features of cardiovascular (CV) risk in stages of gout. Cross-sectional complex multimodal ultrasound study of 169 age-matched patients, with similar distribution of arterial hypertension, diabetes mellitus, obesity and chronic renal failure, was divided into four groups: 41 with asymptomatic hyperuricemia, 52 gout without tophi, 42 gouty tophi and 34 controls with osteoarthritis. Parameters independently associated with CV risk were measured: renal resistive index (RRI), left ventricular mass index (LVMi), mitral annulus early diastolic velocity (e'), intima-media thickness (IMT) and common carotid artery resistive index (CCARI). Multivariate analyses were performed to evaluate the impact of gout stages and CV risk factors on ultrasound alterations. Gouty tophi increased the risk of having IMT >0.90 mm with an OR 11.51 (95 % CI 2.32-57.21, p = 0.003), gout without tophi raised the risk with an OR 6.25 (95 % CI 1.37-28.44, p = 0.018), while asymptomatic hyperuricemia had no effect on IMT. The category of CCARI >0.70 was influenced by tophi with an OR 11.18 (95 % CI 2.61-47.83, p = 0.001) and by arterial hypertension with an OR 3.22 (95 % CI 1.11-9.36, p = 0.032). Neither asymptomatic hyperuricemia nor gout without tophi modified the development of abnormally high CCARI. Gout stages had no impact on LVMi, e' and RRI. Tophi are related to worsened ultrasonographic parameters evaluating target organs in gout, relative to earlier stages of the disease. They create a strong risk of carotid arteries' changes even beyond arterial hypertension.

Path Analysis Identifies Receptor Activator of Nuclear Factor-κB Ligand, Osteoprotegerin, and Sclerostin as Potential Mediators of the Tophus-bone Erosion Relationship in Gout

OBJECTIVE

To determine the relationship between tophus, erosion and bone remodeling factors in gout.

METHODS

Computed tomography bone erosion and circulating bone factors were measured in adults with tophaceous gout. Multiple regression modeling and path analysis were used to determine predictors of erosion.

RESULTS

Tophus number, Māori or Pacific ethnicity, creatinine, receptor activator of nuclear factor-κB ligand (RANKL), osteoprotegerin (OPG), and sclerostin were independently associated with erosion. Path analysis showed a direct effect of tophus number on erosion, partially mediated through OPG, RANKL, and sclerostin.

CONCLUSION

Tophus number is strongly associated with bone erosion in gout. Circulating RANKL, OPG, and sclerostin are potential mediators of tophus-related erosion.

The gouty tophus: a review

The tophus is the cardinal feature of advanced gout. This review summarises recent research into the biology, impact and treatment of tophaceous gout. Microscopically, tophi are chronic foreign body granuloma-like structures containing collections of monosodium urate (MSU) crystals surrounded by inflammatory cells and connective tissue. Extracellular trap formation mediated by neutrophil interactions with MSU crystals may be a central checkpoint in tophus formation. Gouty tophi impact on many aspects of health-related quality of life. Tophi are also implicated in the development of structural joint damage and increased mortality risk in people with gout. Effective treatment of tophaceous gout requires long-term urate-lowering therapy, ideally to achieve a serum urate concentration of <5 mg/dL (300 μmol/L). Recent advances in gout therapeutics have expanded urate-lowering therapy options for patients with severe tophaceous disease to allow faster regression of tophi, improved health-related quality of life and, potentially, improved structural outcomes.

How neutrophil extracellular traps orchestrate the local immune response in gout

Neutrophil granulocytes possess a large arsenal of pro-inflammatory substances and mechanisms that empower them to drive local acute immune reactions to invading microorganisms or endogenous inflammatory triggers. The use of this armory needs to be tightly controlled to avoid chronic inflammation and collateral tissue damage. In gout, inflammation arises from precipitation of uric acid in the form of needle-shaped monosodium urate crystals. Inflammasome activation by these crystals in local immune cells results in a rapid and dramatic recruitment of neutrophils. This neutrophil influx is accompanied by the infamously intense clinical symptoms of inflammation during an acute gout attack. Neutrophilic inflammation however is equipped with a built-in safeguard; activated neutrophils form neutrophil extracellular traps (NETs). At the very high neutrophil densities that occur at the site of inflammation, NETs build aggregates that densely pack the monosodium urate (MSU) crystals and trap and degrade pro-inflammatory mediators by inherent proteases. Local removal of cytokines and chemokines by aggregated NETs explains how acute inflammation can stop in the consistent presence of the inflammatory trigger. Aggregated NETs resemble early stages of the typical large MSU deposits that constitute the pathognomonic structures of gout, tophi. Although tophi contribute to muscosceletal damage and mortality in patients with chronic gout, they can therefore be considered as a payoff that is necessary to silence the intense inflammatory response during acute gout.

Multiarticular tophaceous gout with severe joint destruction: a pictorial overview with a twist

Tophi are the visible dermatological signs of gout. A case of tophaceous gout in a middle-aged man with no other metabolic derangement is being presented with multiple tophi on the hands and feet overlying joints as well as on the fingers and toes. We thought it to be of educational value to demonstrate needle-like crystals of urate by polarizing microscopy. X-rays of hands and feet showed dramatic destructive changes. The patient presented with mottled hypopigmentation on anterior and posterior knees and dorsa of hands and feet where he applied hot “aankda” leaves and covered them with bandage resulting in irritant dermatitis with postinflammatory hypopigmentation. This proved to be a red herring in this case.

Development of a patient-reported outcome measure of tophus burden: the Tophus Impact Questionnaire (TIQ-20)

Background

Tophus burden is currently measured using physical examination and imaging methods. The aim of this study was to develop a patient-reported outcome (PRO) tool to assess tophus burden in people with gout.

Methods

The responses from interviews with 25 people with tophaceous gout were used to generate items for a preliminary PRO tool. Following cognitive testing of each item, a preliminary 34-item questionnaire was administered to 103 people with tophaceous gout. Rasch analysis generated a 20-item Tophus Impact Questionnaire (TIQ-20). Test-retest reproducibility and construct validity of the TIQ-20 were assessed.

Results

The TIQ-20 responses fit the Rasch model and demonstrated unidimensionality, adequate precision, absence of differential item functioning and adequate person separation index. The TIQ-20 included items related to pain, activity limitation, footwear modification, participation, psychological impact and healthcare use due to tophi. In the 103 patients with tophaceous gout, floor effects were observed in 4.9% and ceiling effects in 1%. The TIQ-20 test-retest intraclass correlation coefficient was 0.76 (95% CI 0.61 to 0.85). All predicted correlations for construct validity testing were observed, including weak correlation with serum urate concentrations (r<0.30), moderate correlation with subcutaneous tophus count and dual energy CT urate volume (r=0.30–0.50), and stronger correlation with Health Assessment Questionnaire scores (r>0.50).

Conclusions

We have developed a tophus-specific PRO in patients with tophaceous gout. The TIQ-20 demonstrates acceptable psychometric properties. Initial results show internal, face and construct validity, reproducibility and feasibility. Further research is required to determine responsiveness to change.

Hyperuricaemia and gout: time for a new staging system?

The current widely used clinical staging system for hyperuricaemia and gout describes the symptomatology of gout, but does not capture key aspects of the pathological basis of the disease. We propose a new clinical staging system. Stage A: hyperuricaemia, but without evidence of monosodium urate (MSU) crystal deposition or symptoms of gout. Stage B: MSU crystal deposition by microscopy or advanced imaging, but without signs or symptoms of gout. Stage C: MSU crystal deposition with prior or current symptoms of acute gout flares. Stage D: advanced gout requiring specialist interventions. This proposed new staging system provides a clear focus on gout as a chronic disease of MSU crystal deposition, and provides a rational framework to test the role of screening and treatment of asymptomatic disease.