Dissociation Between Clinical Benefit and Persistent Urate Lowering in Patients with Chronic Refractory Gout Treated with Pegloticase

OBJECTIVE

To assess clinical benefit in patients with chronic refractory gout who did not meet the protocol-defined criteria of responders to pegloticase.

METHODS

This analysis used results from 2 randomized controlled trials (ClinicalTrials.gov: NCT00325195, NCT01356498) to assess the clinical efficacy in responders and nonresponders to treatment (8 mg of pegloticase every 2 weeks). Serum urate was measured before each infusion and the following were recorded: assessment of gout flares, tophus reduction, patient's global assessment (PtGA), tender and swollen joints (TJC and SJC), pain using a 100-mm visual analog scale, and a variety of patient-reported outcomes [Medical Outcomes Study Short Form-36 questionnaire physical component summary score and arthritis-specific health index (ASHI) score].

RESULTS

The analysis included 36 persistent urate responders, 49 nonresponders, and 43 patients who received placebo. Results for both responders and nonresponders indicated significant reduction in tophi and improvements from baseline in PtGA, TJC, SJC, pain, and ASHI. No significant improvements were observed in the patients who received placebo.

CONCLUSION

Chronic refractory gout patients not achieving protocol-defined persistent urate lowering still achieve significant clinical benefits with pegloticase treatment, suggesting that transient reduction in serum urate may result in sustained clinical benefit.

Hospitalization Increases the Risk of Acute Arthritic Flares in Gout: A Population-based Study over 2 Decades

OBJECTIVE

To assess in-hospital gout flares in patients with gout.

METHODS

Hospitalizations were evaluated for gout flares in a cohort of Olmsted County, Minnesota, residents with incident gout in 1989-1992 or 2009-2010.

RESULTS

There were 429 patients followed up to 5 years. Of these, 169 patients experienced 454 hospitalizations. Hospitalization rates increased without reaching statistical significance from 1989-1992 to 2009-2010 [rate ratio (RR) 1.19, 95% CI 0.98-1.45]. The gout flare rate increased significantly during hospitalization (RR 10.2, 95% CI 6.8-14.5). In-hospital gout flare increased the average hospital stay by 1.8 days (p < 0.001).

CONCLUSION

Hospitalization increased the risk of gout flares 10-fold. In-hospital gout flares were associated with longer hospitalization.

Characteristic and Outcome of Psoriatic Arthritis Patients with Hyperuricemia

OBJECTIVE

To determine the characteristics of patients with psoriatic arthritis (PsA) who have hyperuricemia (HUC) and their outcomes, especially cardiovascular (CVD) and kidney diseases.

METHODS

Patients have been followed prospectively at the PsA clinic according to a standard protocol at 6- to 12-month intervals. We defined HUC in men > 450 µmol/l or women > 360 µmol/l. We matched patients with HUC based on sex and age ± 5 years with normal uric acid patients. Demographics information and disease characteristics were reviewed. Outcomes of patients with HUC, especially CVD and kidney diseases, were recorded. Conditional logistic regression was performed to determine factors independently associated with HUC in patients with PsA.

RESULTS

There were 325 (31.9%) out of 1019 patients with PsA who had HUC. Of these, 318 cases were matched to 318 controls. There were 11 (3.4%) out of 325 patients with HUC who had gout. Patients with HUC had longer disease duration and a higher Psoriasis Area and Severity Index. They had more concurrent comorbidities, including CVD and metabolic diseases, as well as higher prevalence of kidney stones and higher creatinine. Only 1 patient with HUC was treated with allopurinol at first evaluation visit and 7 patients during followup. Over the followup, 163 of the 318 patients had persistent HUC (pHUC) for more than 2 visits. Patients with pHUC developed more myocardial infarction, heart failure, and renal impairment. Multivariate analysis showed an association between pHUC, PsA disease duration, and obesity.

CONCLUSION

HUC is common in patients with PsA, especially in those with longer disease duration and obesity. Proper control of HUC and metabolic diseases may play a preventive role in improving PsA outcomes.

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

OBJECTIVE

Lowering serum uric acid (SUA) levels can essentially cure gout; however, this is not widely practiced. To summarize epidemiologic evidence related to this causal link, we conducted a systematic review of the published literature reporting the association between SUA level and incident and recurrent gout (i.e., gout flares).

METHODS

We systematically searched Medline, EMBASE, and the Cochrane Database of Systematic Reviews using separate search strategies for incident gout and recurrent gout. We screened 646 abstracts to identify 8 eligible articles reporting gout incidence and 913 abstracts to identify 18 articles reporting recurrent gout.

RESULTS

For both gout incidence and recurrence, a graded trend was observed where the risk was increased with higher SUA levels. Gout incidence rates per 1000 person-years from population-based studies ranged from 0.8 (SUA ≤ 6 mg/dl) to 70.2 cases (SUA ≥ 10 mg/dl). Recurrent gout risk in clinical cohorts ranged from 12% (SUA ≤ 6 mg/dl) to 61% (SUA ≥ 9 mg/dl) among those receiving urate-lowering therapy (ULT), and 3.7% (SUA 6-7 mg/dl) to 61% (SUA > 9.3 mg/dl) after successful ULT. Retrospective database studies also showed a graded relationship, although the strength of the association was weaker. Studies reporting mean flares or time-to-flare according to SUA showed similar findings.

CONCLUSION

This systematic review confirms that higher SUA levels are associated with increased risk of incident and recurrent gout in a graded manner. Although few prospective cohorts have evaluated incident and recurrent gout according to SUA, the existing evidence underscores the need to treat to SUA targets, as recommended by the American College of Rheumatology and the European League Against Rheumatism.

Effect of Urate Lowering Therapy on Renal Disease Progression in Hyperuricemic Patients with Chronic Kidney Disease

OBJECTIVE

To determine whether urate lowering therapy (ULT) could delay renal disease progression in hyperuricemic patients with chronic kidney disease (CKD).

METHODS

We performed a retrospective review of hyperuricemic patients with stage 3 CKD followed from September 2005 to July 2014 in Dongguk University Ilsan Hospital, Goyang, Korea. A total of 158 eligible patients were identified and 65 of them were treated with ULT in addition to the usual CKD management. We divided the patients according to the use of ULT and compared the estimated glomerular filtration rate (eGFR) change from baseline value and the proportion of renal disease progression (decline of eGFR > 30% of the baseline value, initiation of dialysis or eGFR < 15 ml/min/1.73m(2)) at the time of last followup. Risk factors for renal disease progression were identified by logistic regression analysis.

RESULTS

After a median followup of 118.5 weeks (minimum 25, maximum 465), the ULT group showed better outcomes compared to the non-ULT group in terms of eGFR change from baseline (-1.19 ± 12.07 vs -7.37 ± 11.17 ml/min/1.73 m(2), p = 0.001) and the proportion of renal disease progression (12.3% vs 27.9%, p = 0.01). Goal-directed ULT showed better clinical outcomes compared to maintaining the initial ULT dose. Actual (area under the SUA-time curve adjusted by total observation time period) serum uric acid was significantly associated with the risk of renal disease progression (p for trend = 0.04) and actual serum uric acid level < 7 mg/dl reduced the risk of renal disease progression by 69.4%.

CONCLUSION

ULT significantly delayed renal disease progression in hyperuricemic patients with CKD. Goal-directed ULT seems to be better than continuing the initial ULT prescription.

Treatment of asymptomatic hyperuricemia for the prevention of gouty arthritis, renal disease, and cardiovascular events: a systematic literature review

OBJECTIVE

To systematically review available literature on treatment of hyperuricemia (HU) as a measure of preventing gouty arthritis, renal disease, or cardiovascular events in asymptomatic patients.

METHODS

A systematic literature search was conducted in the Cochrane Library, Medline, Embase, clinical trials registries of the World Health Organization and the US National Institutes of Health, and abstracts from American College of Rheumatology/European League Against Rheumatism meetings, for interventional studies involving adults with no history of gouty arthritis, who were treated for HU. Outcomes of interest included gouty arthritis, renal disease (i.e., renal insufficiency, urate nephropathy, nephrolithiasis), and cardiovascular events (i.e., myocardial infarction, heart failure, ischemic stroke).

RESULTS

A total of 3 studies met the inclusion criteria, 2 studies assessing the prevention of renal disease and 1 study evaluating the potential for delaying progression of preexisting renal disease. In hyperuricemic patients without renal disease, treatment resulted in increased estimated glomerular filtration rate. In hyperuricemic patients with preexisting renal disease, treatment resulted in no significant elevation of serum creatinine over a 1-year followup. However, differences in renal function between the treatment and no-treatment groups were not statistically significant in any of the identified studies.

CONCLUSION

Very limited data are available on the treatment of HU in asymptomatic patients. There is currently insufficient empiric evidence to suggest that lowering serum uric acid level in asymptomatic patients with HU can prevent gouty arthritis, renal disease, or cardiovascular events.

Cardiovascular risk factors and comorbidities in patients with hyperuricemia and/or gout: a systematic review of the literature

OBJECTIVE

To review the available literature on the likelihood of having cardiovascular (CV) risk factors and on developing CV comorbidities in patients with gout and/or asymptomatic hyperuricemia as an evidence base for generating multinational clinical practice recommendations in the 3e (Evidence, Expertise, Exchange) Initiative in Rheumatology.

METHODS

A systematic literature search was carried out using MEDLINE, EMBASE, and The Cochrane Library, and abstracts presented at the 2010/2011 meetings of the American College of Rheumatology (ACR) and the European League Against Rheumatism, searching for CV risk factors and new CV comorbidities in patients with asymptomatic hyperuricemia and/or a diagnosis of gout. Trials that fulfilled predefined inclusion criteria were systematically reviewed.

RESULTS

A total of 66 out of 8918 identified publications were included in this review. After assessment of the risk of bias, 32 articles with a high risk of bias were excluded. Data could not be pooled because of clinical and statistical heterogeneity. In general, both for asymptomatic hyperuricemia and for gout the hazard ratios for CV comorbidities were only modestly increased (1.5 to 2.0) as were the hazard ratios for CV risk factors, ranging from 1.4 to 2.0 for hypertension and from 1.0 to 2.4 for diabetes.

CONCLUSION

Unlike the common opinion that patients with gout or hyperuricemia are at higher risk of developing CV disease, the actual risk to develop CV disease is either rather weak (for hyperuricemia) or poorly investigated (for gout).

Diagnostic value of clinical, laboratory, and imaging findings in patients with a clinical suspicion of gout: a systematic literature review

OBJECTIVE

To analyze the diagnostic utility of clinical, laboratory, and imaging items for gout.

METHODS

A systematic literature search was performed in MEDLINE, EMBASE, and The Cochrane Library; and a manual search of abstracts from the 2010/2011 meetings of the American College of Rheumatology (ACR) and the European League Against Rheumatism, as well as the reference lists of retrieved papers. Studies were included if they evaluated the diagnostic utility of clinical, laboratory, or imaging features or criteria for the diagnosis or classification of gout in adult patients. Two independent reviewers selected papers, extracted the data, and assessed the risk of bias.

RESULTS

Nineteen studies were included in the review; 4 used the identification of monosodium urate (MSU) crystals as the reference standard (RS) and the rest used expert opinion or the ACR preliminary criteria. Most features were evaluated in a single study. Evidence for diagnostic utility, using MSU crystals as RS, of over 50 individual clinical, laboratory, and radiographic features was retrieved. Most items showed a positive likelihood ratio (LR+) < 3, except for the following: response of arthritis to colchicine (LR+ 4.3); presence of tophi on physical examination (LR+ 15.6-30.9); identification of the double-contour sign in ultrasound (US) (LR+ 13.6); and detection of urate deposits by dual-energy computed tomography (DECT) (LR+ 9.5).

CONCLUSION

Individual clinical features show low diagnostic utility, with the exception of tophi and response to colchicine. Some US and DECT findings show better performance than most clinical features.

Clinical characteristics of and relationship between metabolic components and renal function among patients with early-onset juvenile tophaceous gout

OBJECTIVE

Age of onset of gout has recently decreased; however, patients with early-onset gout remain uncommon, and relevant information is scant. We hypothesized that these patients might exhibit differences in serum urates and other comorbidities compared with adult-onset patients.

METHODS

Early-onset gout patients (i.e., juveniles) with (n = 40) and without tophi (n = 47) were enrolled for study. Their clinical characteristics were compared with those of 353 patients with middle-age-onset tophaceous gout and 64 age-matched healthy participants.

RESULTS

Early-onset gout patients with tophi exhibited significantly higher body mass indices and serum urate levels and lower estimated glomerular filtration rates (eGFR) than did those without tophi. Early-onset gout patients with or without tophi demonstrated significantly abnormal lipid profiles and impaired liver or renal function compared with healthy patients. Serum urate levels and gout duration were identified as the principal determinants of tophi development. The presence of tophi might be crucial in decreasing eGFR, which is inversely related to tophi duration or gout duration. Unexpectedly, the most common site of initial gout attacks in early-onset tophaceous gout patients was the ankle, not the toe, which was the most common site in middle-age-onset tophaceous gout patients. The most common site of first tophi occurrence in early-onset patients was a finger, not a toe, which was the most common site in middle-age-onset patients.

CONCLUSION

Early-onset tophaceous gout patients are more likely to exhibit comorbidities and renal dysfunction than middle-age-onset patients and exhibit distinct first sites of gout attack and tophi occurrence patterns.

Common variants of cGKII/PRKG2 are not associated with gout susceptibility

OBJECTIVE

Recently, genetic analyses indicated the association between gout and cGMP-dependent protein kinase 2 (cGKII/PRKG2) gene in a Fukien-Taiwanese heritage population. However, no replication study has been reported in other ancestries. Therefore, we investigated this association in a Japanese population.

METHODS

Genotyping of 4 variants (rs11736177, rs10033237, rs7688672, and rs6837293) of cGKII was performed in 741 male gout patients and 1302 male controls.

RESULTS

cGKII variants have no association with gout.

CONCLUSION

Our replication study suggests that cGKII is not involved in gout susceptibility.

Effect of urate-lowering therapies on renal disease progression in patients with hyperuricemia

OBJECTIVE

To evaluate the association between hyperuricemia and renal disease progression in a real-world, large observational database study.

METHODS

We conducted a population-based retrospective cohort study identifying 111,992 patients with hyperuricemia (> 7 mg/dl) from a large medical group. The final cohort were ≥ 18 years old, urate-lowering therapy (ULT)-naïve, and had the following laboratory results available: at least 1 glomerular filtration rate (GFR) level before the index date and at least 1 serum uric acid (sUA) level and GFR in the followup 36-month period. The cohort was categorized into 3 groups: never treated (NoTx), ULT time receiving therapy of < 80% (< 80%), and ULT time receiving therapy of ≥ 80% (≥ 80%). Outcomes were defined as a ≥ 30% reduction in GFR from baseline, dialysis, or GFR of ≤ 15 ml/min. A subanalysis of patients with sUA < 6 mg/dl at study conclusion was performed. Cox proportional hazards regression model determined factors associated with renal function decline.

RESULTS

A total of 16,186 patients met inclusion criteria. There were 11,192 NoTx patients, 3902 with < 80% time receiving ULT, and 1092 with ≥ 80% time receiving ULT. Factors associated with renal disease progression were age, sex, hypertension, diabetes, congestive heart failure, hospitalizations, rheumatoid arthritis, and higher sUA at baseline. Time receiving therapy was not associated with renal outcomes. Patients who achieved sUA < 6 mg/dl had a 37% reduction in outcome events (p < 0.0001; HR 0.63, 95% CI: 0.5-0.78).

CONCLUSION

Hyperuricemia is an independent risk factor for renal function decline. Patients treated with ULT who achieved sUA < 6 mg/dl on ULT showed a 37% reduction in outcome events.

Serum urate and incidence of kidney disease among veterans with gout

OBJECTIVE

To study the association between serum urate level (sUA) and the risk of incident kidney disease among US veterans with gouty arthritis.

METHODS

From 2002 through 2011 adult male patients with gout who were free of kidney disease were identified in the data from the Veterans Administration VISN 16 database and were followed until incidence of kidney disease, death, or the last available observation. Accumulated hazard curves for time to kidney disease were estimated for patients with average sUA levels > 7 mg/dl (high) versus ≤ 7 mg/dl (low) based on Kaplan-Meier analyses; and statistical comparison was conducted using a log-rank test. A Cox proportional hazard model with time-varying covariates was used to estimate the unadjusted and adjusted hazard ratios for kidney disease.

RESULTS

Eligible patients (n = 2116) were mostly white (53%), with average age 62.6 years, mean body mass index 31.2 kg/m(2), and high baseline prevalence of hypertension (93%), hyperlipidemia (67%), and diabetes (20%). Mean followup time was 6.5 years. The estimated rates of all incident kidney disease in the overall low versus high sUA groups were 2% versus 4% at Year 1, 3% versus 6% at Year 2, and 5% versus 9% at Year 3, respectively (p < 0.0001). After adjustment, high sUA continued to predict a significantly higher risk of kidney disease development (HR 1.43, 95% CI 1.20-1.70).

CONCLUSION

Male veterans with gout and sUA levels > 7 mg/dl had an increased incidence of kidney disease.