Serum Uric Acid and the Risk of Incident and Recurrent Gout: A Systematic Review

Association of urate deposition shown by ultrasound and frequent gout attacks

BACKGROUND

There are few data demonstrating the association between urate burden assessed by ultrasound (US) and gout flares. The aim of this study was to determine the association of urate deposition shown by US and frequent gout attacks.

MATERIALS AND METHODS

Patients with gout were divided into two groups according to the frequency of gout attacks in the previous 12 months: frequent (>2 attacks) and infrequent (0-2 attacks). Urate deposition in the hands, knees, and feet was assessed by US.

RESULTS

Overall, 106 patients were enrolled in this study, of whom 32 (30.1%) had had frequent gout attacks (>2 attacks) in the previous 12 months (the average number of gout attacks was 4.7, range 3-12). Those with frequent gout attacks had significantly longer gout duration, a higher serum urate level, and more urate deposition shown by US than those with infrequent gout attacks (P < 0.05). In both univariate and logistic regression analyses, frequent gout attacks were correlated with gout duration, serum urate level, and urate deposition as shown by US (P < 0.05).

CONCLUSION

These findings indicate that urate deposition shown by US is independently associated with frequent gout attacks. Special attention should be given to the prevention of flares in patients with an initially high urate burden as assessed by US.

Uric acid fluctuation had no effect on renal function among gout patients

BACKGROUND AND AIMS

To investigate the effects of serum uric acid (SUA) level and its fluctuation on renal dysfunction in gout patients.

METHODS AND RESULTS

Data on gout patients was collected from Huzhou city electronic medical record system data sharing platform, and information about relevant diagnoses, prescriptions, biochemical indexes and imaging characteristics was extracted. The gout patients with baseline normal renal function were enrolled in this analysis, and the estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² was defined as renal dysfunction. The generalized estimating equation and Cox regression analysis were used. A total of 1009 patients with gout were enrolled. Compared with the reference group (normal baseline SUA with endpoint SUA to be < 6 mg/dL), endpoint SUA ≥ 10 mg/dL was associated with an increased risk of renal dysfunction (baseline normal SUA group: HR [95% CI] = 3.28 [1.21, 8.91]; baseline high SUA group: HR [95% CI] = 3.01 [1.43, 6.35]). Subgroup analysis of 771 SUA stable gout patients demonstrated that SUA levels at 8-10 (excluding 10), and ≥10 mg/dL were significantly associated with an increased risk for renal dysfunction, with HR [95%CI] to be 1.99 [1.05, 3.77], and 2.98 [1.38, 6.43], respectively.

CONCLUSION

Regardless of the baseline SUA level, SUA >10 mg/dL was a significant risk factor for renal dysfunction. SUA between 6 and 10 mg/dL was a potential risk factor for renal dysfunction. No significant correlation of SUA fluctuation and renal function was found.

Factors associated with achieving target serum uric acid level and occurrence of gouty arthritis: A retrospective observational study of Japanese health insurance claims data

Purpose

This study assessed factors associated with achieving target serum uric acid (sUA) level and occurrence of gouty arthritis in Japanese clinical practice.

Methods

Japanese health insurance claims and medical check‐up data from October 2015 to March 2017 were analyzed to assess factors associated with target sUA achievement in gout and asymptomatic hyperuricemia and gouty arthritis in gout. Target sUA was further assessed by subgroup analysis of urate‐lowering therapy (ULT) prescriptions and outcomes, stratified by renal function.

Results

Patients achieving target sUA tended toward older, female, higher ULT dose, higher adherence, more comorbidities, and/or antidiabetic drugs prescribed. Renal dysfunction and/or diuretic prescriptions were associated with reduced achievement of target sUA. Severe renal dysfunction was particularly influential (odds ratio [OR] = 0.22 [95% confidence interval (CI): 0.10‐0.48] for <15, 0.15 [0.10‐0.23] for ≥15 to <30, compared with eGFR ≥90 mL/min/1.73 m²). Across all renal function categories, mean prescribed ULT dose was low (febuxostat 17.0‐21.0 mg/day, allopurinol 123.1‐139.6 mg/day), and target sUA achievement was reduced among renal dysfunction patients. Gouty arthritis was more likely in patients with a prior history of such occurrences, and less likely for higher ULT adherence, sUA monitored regularly at medical facilities, and/or more comorbidities.

Conclusion

In a real‐world setting, severe renal dysfunction is the most important risk factor for failure to achieve the target sUA, suggesting suboptimal disease management in patients with gout or hyperuricemia complicated by this condition. Findings associated with gouty arthritis suggest that these occurrences could be successfully managed by regular monitoring of sUA and closer adherence to ULT.

Association of Serum Uric Acid Status With Bone Mineral Density in Adolescents Aged 12-19 Years

Aims: Evidence linking serum uric acid (sUA) and bone mineral density (BMD) in adolescents is very limited. To the best of our knowledge, only one report has focused on the relationship between sUA and BMD in adolescents. Thus, this study aimed to determine the association between sUA and total BMD in adolescents aged 12-19 years. Methods: A cross-sectional study was conducted on a sample composed of non-institutionalized US population from the National Health and Nutrition Examination Survey. Weighted multivariate linear regression models were used to evaluate the association between sUA and total BMD. Subgroup analyses were further performed. Results: sUA positively correlated with total BMD in the multiple regression model after adjusting for potential confounders. However, in the subgroup analyses stratified by sex, age, or race/ethnicity, the association between sUA and total BMD followed an inverted U-shaped curve in female adolescents, adolescents aged 16-19 years, and other race/ethnicity. Conclusions: Our results suggested that the correlation between sUA level and total BMD differed by sex. The increased sUA level would be beneficial to bone health in adolescents with low sUA levels, but for female adolescents, a higher sUA level (turning point, 3.9 mg/dL) may have an adverse effect on bone health.

[Advantages of therapy with sodium glucose cotransporter type 2 inhibitors in patients with type 2 diabetes mellitus in combination with hyperuricemia and gout]

Currently, only two drugs for reducing uric acid (UA), allopurinol and febuxostat, are registered in the Russian Federation, but their use does not allow to achieve the target level of UA in all cases. According to the results of numerous randomized trials, hyperuricemia and gout are associated with the corresponding components of the metabolic syndrome, including diabetes mellitus. The influence of factors is due to the need to search for new drugs that have a complex effect on several components of metabolic syndrome at once. Potentially attractive in this regard is a new group of drugs for the treatment of type 2 diabetes mellitus inhibitors of the sodium-glucose cotransporter of type 2, which, in addition to the main hypoglycemic actions, showed positive effects on the cardiovascular system, kidneys, as well as lowering UA.

Urate-induced immune programming: Consequences for gouty arthritis and hyperuricemia

Trained immunity is a process in which innate immune cells undergo functional reprogramming in response to pathogens or damage-associated molecules leading to an enhanced non-specific immune response to subsequent stimulation. While this capacity to respond more strongly to stimuli is beneficial for host defense, in some circumstances it can lead to maladaptive programming and chronic inflammation. Gout is characterized by persistent low-grade inflammation and is associated with an increased number of comorbidities. Hyperuricemia is the main risk factor for gout and is linked to the development of comorbidities. Several experimental studies have shown that urate can mechanistically alter the inflammatory capacity of myeloid cells, while observational studies have indicated an association of hyperuricemia to a wide spectrum of common adult inflammatory diseases. In this review, we argue that hyperuricemia is a main culprit in the development of the long-term systemic inflammation seen in gout. We revisit existing evidence for urate-induced transcriptional and epigenetic reprogramming that could lead to an altered functional state of circulating monocytes consisting in enhanced responsiveness and maladaptive immune responses. By discussing specific functional adaptations of monocytes and macrophages induced by soluble urate or monosodium urate crystals and their contribution to inflammation in vitro and in vivo, we further enforce that urate is a metabolite that can induce innate immune memory and we discuss future research and possible new therapeutic approaches for gout and its comorbidities.

Cross-sectional study of associations between normal body weight with central obesity and hyperuricemia in Japan

BACKGROUND

Several studies have shown that normal weight with central obesity (NWCO) is associated with cardiovascular disease risk factors such as hypertension, dyslipidemia and diabetes. However, the relationship between NWCO and hyperuricemia has not been studied in detail.

METHODS

We investigated the association between NWCO and hyperuricemia among Japanese adults aged 40-64 years who had undergone periodic health examinations between April 2013 and March 2014. Obesity was defined as a body mass index (BMI) ≥25 kg/m² and central obesity was determined as a waist-to-height ratio (WHtR) ≥0.5. We classified the participants into the following groups based according to having obesity and central obesity: normal weight (BMI 18.5-24.9 kg/m²) without (NW; WHtR < 0.5) and with (NWCO) central obesity, and obesity without (OB) and with (OBCO) central obesity. Hyperuricemia was defined as serum uric acid > 7.0 and ≥ 6.0 mg/dL in men and women, respectively, or under medical treatment for hyperuricemia. Alcohol intake was classified as yes (daily and occasional consumption) and none (no alcohol consumption). Odds ratios (OR) and 95% confidence intervals (CI) for hyperuricemia were calculated using a logistic regression model.

RESULTS

We analyzed data derived from 96,863 participants (69,241 men and 27,622 women). The prevalences of hyperuricemia in men and women were respectively, 21.4 and 11.0%, and of participants with NWCO respectively 15.6 and 30.0%. The adjusted OR for hyperuricemia was significantly increased in OBCO compared with NW, regardless of sex (men: OR, 2.12; 95%CI; 2.03-2.21; women: OR, 3.54; 95%CI, 3.21-3.90) and were statistically significant in NWCO compared with NW (men: OR, 1.44; 95%CI, 1.36-1.52; women: OR, 1.41; 95%CI, 1.27-1.57). The results were similar regardless of alcohol consumption.

CONCLUSIONS

We found that NWCO and OBCO were associated with hyperuricemia in middle-aged Japanese men and women. Middle-aged Japanese adults with normal weight but having central obesity should be screened using a combination of BMI and WHtR and educated about how to prevent hyperuricemia.

A Traditional Clinic Chinese Medicine Prescription Qu-Zhuo-Tong-Bi (QZTB) Alleviates Gouty Arthritis in Model Rats

Qu-Zhuo-Tong-Bi (QZTB) is an empirical traditional Chinese medicine prescription for treating acute gouty arthritis clinically without serious adverse effects in mainland China. However, the biochemical mechanism underlying the therapeutic action produced by QZTB treatment against acute gouty arthritis and the effect on recurrent attack remain unknown. In this study, we investigated the anti-inflammatory and analgesic effects of QZTB on acute gouty arthritis and the recurrent attack in rats, as well as the underlying mechanisms. The gouty arthritis model was established by intra-articular injection of monosodium urate (MSU) crystal suspension (2 mg/50 μL) into the right ankle joint of Sprague Dawley (SD) male rats. QZTB (500 mg/kg) and the positive control drug meloxicam were administrated by gavages twice a day for 7 days before, or 3 days after, first MSU injection in different experiments, respectively. The analgesic effects were evaluated by pain-like behaviors and hind paw mechanical withdrawal threshold testing. The anti-inflammatory activities were evaluated by ankle swelling measurement, histologic examination, NLRP3 inflammasome, and inflammatory cytokine expression. Western blot and quantitative real-time PCR were used to detect the protein and mRNA expressions of NLRP3. IL-1β and TNF-α level in the blood serum were detected by enzyme-linked immunosorbent assay (ELISA). QZTB can suppress ankle swelling and synovial inflammation in the MSU-induced gouty arthritis rat model. QZTB alleviated the acute attack and prevented the recurrent attack of gouty arthritis. In addition, QZTB treatment significantly decreased both mRNA and protein levels of NLRP3, as well as the production of IL-1 and TNF-α in the ankle joint of model rats. Taken together, these results suggest that QZTB may be a promising herbal formula for the prevention and treatment of gouty arthritis in humans.

Impact of bariatric surgery on serum uric acid levels and the incidence of gout-A meta-analysis

Gout is characterized by high serum uric acid (SUA) levels and arthritis. It is associated with obesity and metabolic syndrome. Bariatric surgery has been associated with decreased SUA levels and overall gout incidence. This meta-analysis aims to summarize the current evidence on bariatric surgery, gout and SUA levels. A literature review was performed on papers published from 2000 up till December 2018. Original studies investigating the impact of bariatric surgery on SUA levels or gout incidence were evaluated. Twenty studies with a total of 5,233 patients were analysed. Majority (n=14) had a follow-up duration of at least 12 months. The mean preoperative body mass index (BMI) was 45.2kg m^-2 . The mean preoperative SUA level was 6.5mg dL^-1 . Subgroup analysis demonstrated a mean decrease in SUA levels (-0.73mg dL^-1 ) from the third postoperative month onwards, which was sustained until the third postoperative year (-1.91mg dL^-1 ). There was a rise in SUA levels in the first post-operative month. Meta-regression analyses demonstrated a proportionate linear relationship between the change in BMI and SUA levels. Post-bariatric surgery weight loss is associated with reduced SUA levels and decreased incidence of gout attacks. However, this is only evident from the third post-operative month onwards.

Making the right thing the easy thing to do: strategies to improve outcomes in gout

The burden of gout is increasing worldwide. Although urate-lower ing drugs have been available for more than half a century, the initiation and persistence of urate-lowering therapy remain low. Health-care system, practitioner, and patient barriers contribute to the clinical inertia in gout management. Pervasive beliefs about gout as a disease of an indulgent lifestyle that should be managed primarily with dietary modification are key barriers that prevent patients from receiving effective therapy. In light of safety concerns about newer urate-lowering medications, allopurinol, an inexpensive generic medication, is likely to remain the first-line urate-lowering therapy for the foreseeable future. Ensuring that allopurinol is optimally and persistently prescribed is a priority for improved gout management. A health literacy approach that focuses on patient understanding of gout as a chronic disease that requires behaviour change to take long term urate-lowering therapy is important. This approach provides a clear rationale for long-term urate-lowering therapy that is able to dissolve the monosodium urate crystals and ultimately prevent the symptoms of gout. Patient-centred models that use the skills of nurses and pharmacists to facilitate patient understanding can lead to major improvements in gout care. Additionally, systematic quality improvement approaches within practices, while reducing inconvenience and cost to patients, should be a priority.

Gout

Gout is a chronic disease caused by monosodium urate (MSU) crystal deposition. Gout typically presents as an acute, self-limiting inflammatory monoarthritis that affects the joints of the lower limb. Elevated serum urate level (hyperuricaemia) is the major risk factor for MSU crystal deposition and development of gout. Although traditionally considered a disorder of purine metabolism, altered urate transport, both in the gut and the kidneys, has a key role in the pathogenesis of hyperuricaemia. Anti-inflammatory agents, such corticosteroids, NSAIDs and colchicine, are widely used for the treatment of gout flare; recognition of the importance of NLRP3 inflammasome activation and bioactive IL-1β release in initiation of the gout flare has led to the development of anti-IL-1β biological therapy for gout flares. Sustained reduction in serum urate levels using urate-lowering therapy is vital in the long-term management of gout, which aims to dissolve MSU crystals, suppress gout flares and resolve tophi. Allopurinol is the first-line urate-lowering therapy and should be started at a low dose, with gradual dose escalation. Low-dose anti-inflammatory therapies can reduce gout flares during initiation of urate-lowering therapy. Models of care, such as nurse-led strategies that focus on patient engagement and education, substantially improve clinical outcomes and now represent best practice for gout management.

Clinical Characteristics of Early-Onset Gout in Outpatient Setting

Objective

The objective of this study is to investigate the clinical characteristics and treatment of patients with early-onset gout.

Methods

We retrospectively reviewed 327 adult patients with a first diagnosis of gout from 2008 to 2016 using the database of a multispecialty group practice in New England. Patients were classified into the following groups: age 30 years or younger at first diagnosis (group 1), age 31-40 years (group 2), and age over 40 years (group 3). The clinical characteristics and treatment of gout were compared among the three groups.

Results

We identified 87 patients in group 1 and 140 patients in group 2. Group 3 included 100 patients randomly chosen from the 7216 patients with a first diagnosis at age over 40 years. Patients within group 1 had significantly higher serum uric acid (sUA) levels at the time of diagnosis and a more prominent family history of gout. Younger patients (groups 1 and 2) had a significantly higher body mass index than patients over 40 years of age (group 3). A substantial number of younger patients also had hypertension or hyperlipidemia. The majority of younger patients met the 2012 American College of Rheumatology (ACR) guidelines for initiating urate-lowering therapy (ULT) on the basis of frequency of gout attacks, whereas the majority of patients over 40 years of age met the guidelines for ULT on the basis of chronic kidney disease. Patients over 40 years of age were more likely to achieve an sUA level less than 6.0 mg/dl.

Conclusion

Patients with a first diagnosis of gout at age 40 years or younger frequently had cardiovascular risk factors and were less likely to achieve an sUA level less than 6.0 mg/dl compared with patients over 40 years of age who were treated in routine clinical practice. Clinicians should be aware that patients with early-onset gout may be an undertreated population with poor adherence to ULT and increased risk of recurrent gout and cardiovascular diseases.

2018 updated European League Against Rheumatism evidence-based recommendations for the diagnosis of gout

Although gout is the most common inflammatory arthritis, it is still frequently misdiagnosed. New data on imaging and clinical diagnosis have become available since the first EULAR recommendations for the diagnosis of gout in 2006. This prompted a systematic review and update of the 2006 recommendations. A systematic review of the literature concerning all aspects of gout diagnosis was performed. Recommendations were formulated using a Delphi consensus approach. Eight key recommendations were generated. A search for crystals in synovial fluid or tophus aspirates is recommended in every person with suspected gout, because demonstration of monosodium urate (MSU) crystals allows a definite diagnosis of gout. There was consensus that a number of suggestive clinical features support a clinical diagnosis of gout. These are monoarticular involvement of a foot or ankle joint (especially the first metatarsophalangeal joint); previous episodes of similar acute arthritis; rapid onset of severe pain and swelling; erythema; male gender and associated cardiovascular diseases and hyperuricaemia. When crystal identification is not possible, it is recommended that any atypical presentation should be investigated by imaging, in particular with ultrasound to seek features suggestive of MSU crystal deposition (double contour sign and tophi). There was consensus that a diagnosis of gout should not be based on the presence of hyperuricaemia alone. There was also a strong recommendation that all people with gout should be systematically assessed for presence of associated comorbidities and risk factors for cardiovascular disease, as well as for risk factors for chronic hyperuricaemia. Eight updated, evidence-based, expert consensus recommendations for the diagnosis of gout are proposed.

Pegloticase Treatment Significantly Decreases Blood Pressure in Patients With Chronic Gout

Serum urate is correlated with blood pressure (BP), and lowering urate may decrease BP, but a consistent effect has not been observed. Here, we evaluated whether pegloticase, a recombinant uricase conjugated to polyethylene glycol, which can lead to persistently low serum urate levels (<1 mg/dL), can modulate BP in subjects with chronic refractory gout. This post hoc analysis used results from two 6-month randomized clinical trials in which subjects were treated with 8 mg pegloticase every 2 or 4 weeks (q2w or q4w) or placebo. Responders in this study were defined as those individuals in whom a persistently low urate level (<6 mg/dL and usually <1 mg/dL) was maintained. Serial sitting BP was measured in 173 subjects, and estimated glomerular filtration rate was determined at baseline and after 3 and 6 months. Significant reductions in mean arterial pressure (MAP) from baseline to 6 months were noted in q2w responders ( P=0.0028), whereas reductions in MAP in other groups were not significant. Significant decreases in both systolic and diastolic BP paralleled the change in MAP. Of the 62% of q2w responders exhibiting persistent decreases in MAP, there were no significant differences in baseline age, sex, race, weight, body mass index, history of hypertension, hyperlipidemia, history of coronary artery disease, gout duration, MAP, serum urate, estimated glomerular filtration rate or urinary uric acid/creatinine ratio compared with those who did not lower MAP. No significant changes in estimated glomerular filtration rate occurred in any of the groups during the study. Responders to biweekly pegloticase who maintained a persistently lower serum urate level throughout the trial experienced significant reductions in both systolic and diastolic BP that were independent of changes in renal function. Clinical Trial Registration- URL: http://www.clinicaltrials.gov . Unique identifier: NCT00325195.

Achievement of Target Serum Uric Acid Levels and Factors Associated with Therapeutic Failure among Japanese Men Treated for Hyperuricemia/Gout

Objective To assess the rate of successfully achieving treatment goals among Japanese men with hyperuricemia/gout and identify factors influencing the success rate. Methods This cross-sectional study, conducted from January to December 2012, examined the serum uric acid (SUA) levels and clinical characteristics of 2,103 men with hyperuricemia/gout selected from an initial population of 136,770 individuals who participated in a workplace health checkup. The success rates (defined as SUA ≤6.0 mg/dL) were calculated, and a multivariate analysis was used to identify factors associated with "therapeutic failure" to achieve target SUA levels. Results The rate of successfully achieving the target SUA level was 37.5%. The body mass index (BMI) was significantly associated with therapeutic failure [25.0≤ Category (C) 2<27.5, adjusted odds ratio (AOR) =1.35; 27.5≤C3<30.0, AOR=1.69; C4 ≥ 30.0, AOR=1.94; relative to C1<25.0]. A significant positive association was also observed between waist circumference (WC) and therapeutic failure (85≤C2<90, OR=1.29; 90≤C3<95, OR=1.41; 95≤C4, OR=2.28; relative to C1<85.0 cm). Those with higher BMI/WC measurements were significantly more likely to have higher SUA levels than those with lower such measurements. The ongoing intake of dyslipidemia medication was identified as a protective factor against therapeutic failure. Discussion Our findings suggest a possible association between obesity and therapeutic failure, underscoring the importance of maintaining lipid profiles as part of managing SUA levels. Better management of both obesity and dyslipidemia may prevent future cardiovascular disorders by ensuring healthier SUA levels.

Impact of Non-Adherence and Flare Resolution on the Cost-Effectiveness of Treatments for Gout: Application of a Linked Pharmacometric/Pharmacoeconomic Model

BACKGROUND

Dual urate-lowering therapy (ULT) with lesinurad in combination with either allopurinol or febuxostat is an option for patients with gout unsuccessfully treated on either monotherapy. Treatment failure is often a result of poor medication adherence. Imperfect adherence in clinical trials may lead to biased estimates of treatment effect and confound the results of cost-effectiveness analyses.

OBJECTIVES

To estimate the impact of varying medication adherence on the cost effectiveness of lesinurad dual therapy and estimate the value-based price of lesinurad at which the incremental cost-effectiveness ratio is equal to £20,000 per quality-adjusted life-year (QALY).

METHODS

Treatment effect was simulated using published pharmacokinetic-pharmacodynamic models and scenarios representing adherence in clinical trials, routine practice, and perfect use. The subsequent cost and health impacts, over the lifetime of a patient cohort, were estimated using a bespoke pharmacoeconomic model.

RESULTS

The base-case incremental cost-effectiveness ratios comparing lesinurad dual ULT with monotherapy ranged from £39,184 to £78,350/QALY gained using allopurinol and £31,901 to £124,212/QALY gained using febuxostat, depending on the assumed medication adherence. Results assuming perfect medication adherence imply a per-quarter value-based price of lesinurad of £45.14 when used in dual ULT compared with allopurinol alone and £57.75 compared with febuxostat alone, falling to £25.41 and £3.49, respectively, in simulations of worsening medication adherence.

CONCLUSIONS

The estimated value-based prices of lesinurad only exceeded that which has been proposed in the United Kingdom when assuming both perfect drug adherence and the eradication of gout flares in sustained treatment responders.

How should we manage asymptomatic hyperuricemia?

The definition of asymptomatic hyperuricemia remains unclear, as no consensus exists about the serum urate cutoff or the relevance of ultrasound findings. Comorbidities associated with hyperuricemia have increased in frequency over the past two decades. Hyperuricemia (and/or gout) may be a cause or a consequence of a comorbidity. Whereas epidemiological studies suggest that hyperuricemia may be linked to cardiovascular, metabolic, and renal comorbidities, Mendelian randomization studies have not provided proof that these links are causal. Discrepancies between findings from observational studies and clinical trials preclude the development of recommendations about the potential benefits of urate-lowering therapy (ULT) in individual patients with asymptomatic hyperuricemia. The risk/benefit ratio of ULT is unclear. The risk of developing gout, estimated at 50%, must be weighed against the risk of cutaneous and cardiovascular side effects of xanthine oxidase inhibitors. The need for optimal comorbidity management, in contrast, is universally accepted. Medications for comorbidities that elevate urate levels should be discontinued and replaced with medications that have the opposite effect. Therapeutic lifestyle changes, weight loss as appropriate, and sufficient physical activity are useful for improving general health. Whether ULT has beneficial effects on comorbidities will be known only when well-powered interventional trials with relevant primary endpoints are available.

A Practical Guide for Treatment of Rapidly Progressive ADPKD with Tolvaptan

In the past, the treatment of autosomal dominant polycystic kidney disease (ADPKD) has been limited to the management of its symptoms and complications. Recently, the US Food and Drug Administration (FDA) approved tolvaptan as the first drug treatment to slow kidney function decline in adults at risk of rapidly progressing ADPKD. Full prescribing information approved by the FDA provides helpful guidelines but does not address practical questions that are being raised by nephrologists, internists, and general practitioners taking care of patients with ADPKD, and by the patients themselves. In this review, we provide practical guidance and discuss steps that require consideration before and after prescribing tolvaptan to patients with ADPKD to ensure that this treatment is implemented safely and effectively. These steps include confirmation of diagnosis; identification of rapidly progressive disease; implementation of basic renal protective measures; counseling of patients on potential benefits and harms; exclusions to use; education of patients on aquaresis and its expected consequences; initiation, titration, and optimization of tolvaptan treatment; prevention of aquaresis-related complications; evaluation and management of liver enzyme elevations; and monitoring of treatment efficacy. Our recommendations are made on the basis of published evidence and our collective experiences during the randomized, clinical trials and open-label extension studies of tolvaptan in ADPKD.

The risk of clinically diagnosed gout by serum urate levels: results from 30 years follow-up of the Malmö Preventive Project cohort in southern Sweden

Background

Hyperuricemia (HU) is in the causal pathway for developing clinical gout. There are few population-based assessments of the absolute and relative risk of clinically diagnosed incident gout in subjects with HU. We aimed to explore the long-term risk of developing incident gout among asymptomatic adults with different levels of serum urate (SU).

Methods

Malmö Preventive Project was a population-based screening program for cardiovascular risk factors, alcohol abuse, and breast cancer in Malmö, Sweden. The study population was screened between 1974 and 1992. At baseline, subjects were assessed with a questionnaire, physical examination, and laboratory tests. Follow-up ended at first gout diagnosis, death, moving from area, or December 31, 2014. Incident gout (using ICD10 codes) was diagnosed based on national registers for specialized inpatient and outpatient care, and from 1998 onward in the Skåne Healthcare Register including primary healthcare. Incidence rates, absolute risk, hazard ratios (HRs) and potentially associated factors were analyzed by baseline SU levels, i.e. normal levels (≤ 360 μmol/L); 361–405 (levels below tissue solubility of SU), and > 405 (HU), overall, and by sex.

Results

Overall, 1275 individuals [3.8%; 1014 men (4.5%) and 261 women (2.4%)] of the 33,346 study participants (mean age: 45.7 (SD: 7.4), 67% men), developed incident gout during follow-up (mean 28.2 years). Of those with HU, 14.7% of men and 19.5% of women developed gout. Compared to subjects in the lowest SU category, the age-adjusted HR in men increased from 2.7 to 6.4, and in women from 4.4 to 13.1 with increasing baseline SU category, and with a statistically significant interaction of sex (p < 0.001). Body mass index, estimated glomerular filtration rate (negative), triglycerides, alcohol risk behavior (only in men), and comorbidities such as hypertension, cardiovascular disease, and diabetes were strongly associated with SU at baseline in both sexes.

Conclusions

The absolute risk for developing clinically diagnosed gout over 30 years in middle-aged subjects was 3.8%, and increased progressively in both men and women in relation to baseline SU. This risk increase was significantly higher in women than in men, whereas the associations between baseline risk markers and SU levels were similar in both sexes.

Non-pharmacologic measures for gout management in the prospective GOSPEL cohort: Physicians' practice and patients' compliance profiles

OBJECTIVES

Gout management includes non-pharmacological measures (NPM). The main objective of this study was to describe the NPM proposed by physicians and their implementation by patients after 3-6 months. The secondary objective was to identify NPM compliance profiles among these patients.

METHODS

Ancillary observational study using the GOSPEL French cohort of 1003 patients with gout, based on questionnaires for physicians and patients at inclusion and then after 3-6 months. Patients were included by a representative sample of 398 general practitioners (GP) and 109 private-practice rheumatologists. Modifiable risk factors of hyperuricemia and proposed NPM were compared. Patient compliance profiles were identified by multiple correspondence and hierarchical clustering analysis.

RESULTS

The study included 630 patients: 80.7% were obese or overweight, 51% reported excessive alcohol consumption. Physicians identified fewer modifiable risk factors than their real prevalence in the cohort. Physicians proposed NPM to 57% of patients, particularly diet modifications (46.4%). Increasing physical activity (P < 0.0001) was the best followed NPM. The physician's influence in the decision of starting NPM was more frequent among GPs' patients (P = 0.01). Three patients' compliance profiles were identified. "Very good responders" (55.8%) implemented all the proposed NPM. "Good responders" (12.7%) had a more severe disease and followed the proposed NPM, but for alcohol consumption. "Bad responders" (31.5%) did not modify their life style: these were older patients with a very recent gout diagnosis.

CONCLUSION

More personalized care about NPM requires adapting the practitioner's approach to patients' compliance profiles, especially elderly patients with recent gout.

Identification of monosodium urate crystal deposits in patients with asymptomatic hyperuricemia using dual-energy CT

Objectives

Dual-energy CT (DECT) scan is a sensitive and specific tool used to visualise and quantify monosodium urate (MSU) crystal deposits in the joints. Few studies have examined MSU crystal deposits in patients with asymptomatic hyperuricemia (ie, hyperuricemia in the absence of gout) using DECT.

Methods

We conducted a prospective, non-interventional cross-sectional study to detect MSU crystal deposits on DECT scans among patients with asymptomatic hyperuricemia. We also examined patient factors associated with subclinical MSU crystal deposits. Out of 130 subjects aged ≥40 years with metabolic syndrome screened for serum uric acid (sUA) levels ≥6.5 mg/dL, 46 underwent a foot/ankle DECT scan.

Results

The mean age of the study participants was 62 (±8) years, 41% were men and the mean sUA level was 7.8 (±1.0) mg/dL. Seven (15%) of 46 patients had MSU crystal deposits on DECT with a mean total volume of 0.13 (±0.14) cm³. In the univariable logistic regression analysis, older age had a significant association with presence of MSU crystal deposits (OR 1.20, 95% CI 1.03 to 1.39), but sUA did not (OR 1.36, 95% CI 0.63 to 2.95). In the univariable analysis, sUA levels showed a trend towards a modest linear association (β=0.11, P=0.09) with total volume of MSU crystal deposits.

Conclusions

Fifteen per cent of patients with asymptomatic hyperuricemia had subclinical MSU crystal deposits on foot/ankle DECT scans. Older age, but not sUA, was significantly associated with presence of subclinical MSU crystal deposits among patients with asymptomatic hyperuricemia. Clinical significance of these subclinical MSU crystal deposits needs to be determined.

What Is the Evidence for Treat-to-Target Serum Urate in Gout?

PURPOSE OF REVIEW

Most current clinical guidelines for gout management advocate a treat-to-target serum urate approach, although notable differences exist. Serum urate is a rational target for gout treatment given the central role of urate in disease causality, its association with key outcomes and its practicality of use in clinical practice. This review analyses the evidence for this strategy in gout.

RECENT FINDINGS

Recent studies have confirmed the efficacy of urate-lowering therapy in achieving serum urate targets, both in trials using fixed doses and those applying a treat-to-target strategy. In a limited number of long-term studies (> 12-month duration), interventions that incorporate a treat-to-target serum urate approach have been shown to promote regression of tophi, reduce the frequency of gout flares and improve MRI-detected synovitis. A strong case can be made for a treat-to-target serum urate strategy in gout, supported by existing knowledge of disease pathophysiology, outcomes from urate-lowering therapy studies and emerging results of randomised strategy trials of sufficient duration.

Ultrasonography and dual-energy computed tomography provide different quantification of urate burden in gout: results from a cross-sectional study

Background

Ultrasonography (US) and dual-energy computed tomography (DECT) can assess urate burden in gout. The objective of this study was to compare the quantification of urate deposition provided by US to the one provided by DECT.

Methods

Patients with a diagnosis of gout were prospectively recruited to undergo quantification of urate deposition using US and DECT. US examination for tophi and the double contour (DC) sign was performed on the knees and feet and corresponding DECT scans provided volumes of tophi and of overall urate deposition. The primary endpoint was the intra-class correlation coefficient (ICC) of the volume of the index tophus measured by US and DECT and its 95% confidence interval (CI 95%).

Results

Of the 64 patients included, 34 presented with at least one tophus on US. DECT inter-reader agreement for urate deposition was perfect with an ICC of 1 (1–1) and good for the measurement of the index tophus with an ICC of 0.69 (0.47–0.83). The ICC for the measurement of the index tophus between the two techniques was poor with a value of 0.45 (0.1–0.71). The average ratio between the index tophi volume as assessed by DECT and US was 0.65. The number of DC-positive joints did not correlate with DECT volume of overall deposits (Spearman correlation coefficient of 0.23).

Conclusions

DECT measurements of tophi give smaller volumes to the same tophi measured with US, and US signs of urate deposition in joints do not correlate with overall DECT volumes of extra-articular deposition.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1381-2) contains supplementary material, which is available to authorized users.

The genetics of gout: towards personalised medicine?

Over the last decade, there have been major advances in the understanding of the genetic basis of hyperuricaemia and gout as well as of the pharmacogenetics of urate-lowering therapy. Key findings include the reporting of 28 urate-associated loci, the discovery that ABCG2 plays a central role on extra-renal uric acid excretion, the identification of genes associated with development of gout in the context of hyperuricaemia, recognition that ABCG2 variants influence allopurinol response, and the impact of HLA-B*5801 testing in reducing the prevalence of allopurinol hypersensitivity in high-risk populations. These advances, together with the reducing cost of whole genome sequencing, mean that integrated personalised medicine approaches may soon be possible in clinical practice. Genetic data may inform assessment of disease prognosis in individuals with hyperuricaemia or established gout, personalised lifestyle advice, selection and dosing of urate-lowering therapy, and prevention of serious medication adverse effects. In this article, we summarise the discoveries from genome-wide association studies and discuss the potential for translation of these findings into clinical practice.

Individualising the dose of allopurinol in patients with gout

AIMS

The aims of the study were to: 1) determine if a plasma oxypurinol concentration-response relationship or an allopurinol dose-response relationship best predicts the dose requirements of allopurinol in the treatment of gout; and 2) to construct a nomogram for calculating the optimum maintenance dose of allopurinol to achieve target serum urate (SU) concentrations.

METHODS

A nonlinear regression analysis was used to examine the plasma oxypurinol concentration- and allopurinol dose-response relationships with serum urate. In 81 patients (205 samples), creatinine clearance (CL_CR ), concomitant diuretic use and SU concentrations before (U_P ) and during (U_T ) treatment were monitored across a range of allopurinol doses (D, 50-700 mg daily). Plasma concentrations of oxypurinol (C) were measured in 47 patients (98 samples). Models (n = 47 patients) and predictions from each relationship were compared using F-tests, r² values and paired t-tests. The best model was used to construct a nomogram.

RESULTS

The final plasma oxypurinol concentration-response relationship (U_T  = U_P  - C*(U_P  - U_R )/(ID₅₀  + C), r²  = 0.64) and allopurinol dose-response relationship (U_T  = U_P  - D^* (U_P  - U_R )/(ID₅₀  + D), r²  = 0.60) did not include CL_CR or diuretic use as covariates. There was no difference (P = 0.87) between the predicted SU concentrations derived from the oxypurinol concentration- and allopurinol dose-response relationships. The nomogram constructed using the allopurinol dose-response relationship for all recruited patients (n = 81 patients) required pretreatment SU as the predictor of allopurinol maintenance dose.

CONCLUSIONS

Plasma oxypurinol concentrations, CL_CR and diuretic status are not required to predict the maintenance dose of allopurinol. Using the nomogram, the maintenance dose of allopurinol estimated to reach target concentrations can be predicted from U_P .