Efficacy and safety of tart cherry supplementary citrate mixture on gout patients: a prospective, randomized, controlled study

BACKGROUND

Low urine pH, which may be mediated by metabolic syndrome (MetS), is common in gout. Tart cherries are shown to improve MetS symptoms and possess anti-inflammatory properties. However, the efficacy of tart cherry supplements on urine pH has yet to be studied.

OBJECTIVES

This study aimed to investigate the efficacy and safety of tart cherry supplementary citrate (TaCCi) mixture on urine pH, serum urate (sUA), C-reactive protein (CRP), and gout flares in gout patients initiating urate-lowering therapy (ULT), in comparison to citrate mixture and sodium bicarbonate.

METHODS

A prospective, randomized (1:1:1), open-label, parallel-controlled trial was conducted among 282 men with gout and fasting urine pH ≤ 6, who were initiating ULT with febuxostat (initially 20 mg daily, escalating to 40 mg daily if serum urate ≥ 360 μmol/L). Participants were randomized to groups taking either sodium bicarbonate, citrate mixture, or TaCCi mixture. All participants were followed every 4 weeks until week 12. Urine pH and sUA were co-primary outcomes, with various biochemical and clinical secondary endpoints.

RESULTS

Urine pH increased to a similar extent in all three groups. SUA levels declined in all three groups as well, with no significant differences observed between the groups. At week 12, the TaCCi mixture group exhibited a greater reduction in the urine albumin/creatinine ratio (UACR) compared to the other two groups (p < 0.05). Participants taking TaCCi mixture or citrate mixture experienced fewer gout flares than those in the sodium bicarbonate group over the study period (p < 0.05). Additionally, the TaCCi mixture group had a lower CRP level at week 12 relative to the other two groups (p < 0.01). Adverse events were similar across all three groups.

CONCLUSION

The TaCCi mixture had similar efficacy and safety on urine alkalization and sUA-lowering as the citrate mixture and sodium bicarbonate in patients with gout. However, the TaCCi mixture resulted in greater improvements in UACR and CRP, which suggests that tart cherry supplements may provide additional benefits for renal protection and reduce inflammation in gout, particularly when starting ULT.

TRIAL REGISTRATION

This project was registered in ChiCTR ( www.chictr.org.cn ), with the registration number: ChiCTR2100050749.

A Study of Metabolic Parameters in Patients with Gout: A Single Center Study from Nepal

BACKGROUND AND AIMS

To study the prevalence of deranged metabolic parameters in patients with gout.

METHODS

This was a prospective, cross-sectional observational study conducted at a tertiary level rheumatology center in Nepal. Patients over 18 years and diagnosed as gout using the ACR/EULAR 2015 classification criteria were included in the study. Known cases of chronic kidney disease, liver disease and heart diseases were excluded. Baseline demographic data along with records of weight, waist circumference, lipid profile, glucose profile, blood pressure measurement, serum uric acid level and inflammatory markers were taken. Diagnosis of metabolic syndrome (MS) was made according to the National Cholesterol Education Program criteria. Approval was obtained from the ethical review board of the National Center for Rheumatic Diseases.

RESULTS

A total of 523 patients with gout were enrolled in the study, out of which 97.0% were male. The mean age at diagnosis was 49.1±12.8 years. Most of the patients were overweight with a mean BMI of 27.0±3.6 kg/m2. About 8.1% had preexisting diabetes mellitus, 24.6% had hypertension, 5.1% had hypothyroidism and 45.1% had dyslipidemia. Patients fulfilling 2 out of 5 criteria of MS were 60.6% whereas 30.6% fulfilled 3 out of 5 criteria.

CONCLUSION

Gout was commonly observed in middle-aged men. The prevalence of metabolic syndrome and its components was high in patients with gout. Management of gout should also include screening and management of the metabolic syndrome.

Hyperuricemia and Impaired Renal Function: A Prospective Cohort Study

Background

Related studies have demonstrated a relationship of elevated serum uric levels with a decline in kidney function. However, limited evidence exists in a Southeast Asian community-based population.

Objective

The study aimed to examine the relationship between serum uric acid levels and impaired renal function.

Methods

A prospective cohort study was conducted in the Thai army health checkup population between July 1, 2006 and December 31, 2012. Inclusion criteria included age older than 20 years and baseline estimated glomerular filtration rate (eGFR) over 60 mL/min/1.73 m². Cox regression analysis was used to evaluate the association between incidence of impaired renal function and baseline serum uric acid quartiles. Impaired renal function was defined as eGFR <60 mL/min/1.73 m² over 3 months.

Results

A total of 9,534 participants (7,474 men and 2,060 women) were enrolled. Cox regression analysis revealed a significant association of serum uric acid level with impaired renal function in the whole population as the unadjusted hazard ratio (HR) (95% CI) of impaired renal function in second, third, and fourth quartiles were 2.1 (1.39, 3.17), 2.39 (1.6, 3.59), and 3.94 (2.71, 5.74), respectively, when compared with serum uric acid in the first quartile, respectively. After adjusting in 2 models, the HR still significantly persisted with similar magnitudes in all quartiles. Higher incidences of impaired renal function were observed among males than among females in all quartiles. Kaplan-Meier curve showed better renal survival rate in the lower quartile groups. Linear regression analysis showed that eGFR negatively correlated with serum uric acid (r = -0.213, p < 0.001).

Conclusion

Our study suggests that an independent association exists of serum uric acid levels with the incidence of impaired renal function and renal progression in the Southeast Asian community-based population.

Gout is associated with elevated risk of erectile dysfunction: a systematic review and meta-analysis

Previous studies investigating the risk of erectile dysfunction (ED) among patients with gout have produced inconsistent evidence. Therefore, the aim of this meta-analysis was to investigate the relationship between gout and the risk of ED. The Embase, Medline, Scopus, Web of Science and Cochrane Library databases were searched for all studies assessing the risk of ED in patients with gout. Relative risks (RR) and corresponding 95% confidence intervals (CI) were adopted to estimate the association between gout and the risk of ED. Sensitivity analyses were applied to evaluate the robustness of results. Overall, 355,761 participants were included from 8 studies (3 cross-sectional and 5 cohort studies). Of these, 85,067 were patients with gout. Synthesis results showed patients with gout had a 1.2-fold higher risk of ED than individual without gout (RR 1.20, 95% CI 1.10-1.31, P < 0.001). The results of sensitivity analysis are consistent with the trend of synthesis results. The present meta-analysis revealed that the risk of ED in patients with gout was dramatically increased when compared with the general population, which suggests that clinicians should assess erectile function when treating an individual who suffers from gout.

Prevalence and characteristics of metabolic syndrome in gout patients in a hospital setting in sub-Saharan Africa

BACKGROUND

Evidence from epidemiological studies suggests an important association between gout and the metabolic syndrome (MetS). However, to the best of our knowledge, prevalence of metabolic syndrome in gout has not been reported in sub-Saharan African (SSA) settings.

OBJECTIVES

The aim of this study was to determine the prevalence and characteristics of MetS in gout in a SSA population.

METHOD

After prior ethical clearance, we carried out a cross-sectional study involving gout patients in a referral hospital in Douala-Cameroon. Metabolic syndrome was defined using International Diabetes Foundation criteria. Associations between variables were assessed using logistic regression.p <  0.05 was considered significant.

RESULTS

On 174 gout patients (48.3% females) who consented to participate in the study, the median (IQR) age was 55.00 (14.25) years, and the median (IQR) duration of gout was 7.5 (10.0) years. Prevalence of metabolic syndrome was 54.6% (95% CI: 47.9%-62.8%). One hundred and forty-seven (84.5%) participants had central obesity, 62 (35.6%) raised triglycerides, 79 (45.4%) reduced HDL-C, 129 (74.1%) raised blood pressure, and 85 (48.9%) had raised fasting plasma glucose. On logistic regression analyses, gout patients with metabolic syndrome significantly had a higher body mass index (OR: 1.09, 95% CI: 1.02-1.17), and higher levels of serum uric acid (OR: 1.02, 95% CI: 1.01-1.04).

CONCLUSIONS

About 1 out of every 2 gout patients in this population have metabolic syndrome. These gout patients with metabolic syndrome significantly have a higher body mass index, and higher levels of serum uric acid. Cohort studies are required to clearly establish the direction of the relationship between gout and metabolic syndrome.

Metabolic syndrome: prevalence and risk factors in Korean gout patients

BACKGROUND/AIMS

We performed this study to investigate associations between metabolic syndrome, chronic kidney disease (CKD), and gout.

METHODS

We reviewed the medical records of 151 patients with gout at the Department of Rheumatology in Korea University Ansan Hospital. The following measures were examined: waist circumference, blood pressure, alcohol consumption, and levels of triglyceride, high density lipoprotein cholesterol, fasting serum glucose, serum uric acid (SUA), creatinine, insulin, and C-peptide. We assessed metabolic syndrome by the homeostasis model assessment of insulin resistance (HOMA-IR) index and renal function by the Modification of Diet in Renal Disease equation; patients were classified according to World Health Organization Asia-Pacific obesity criteria.

RESULTS

The prevalence of metabolic syndrome in gout patients (50.8%) was higher than in non-gout patients. The mean SUA level was significantly higher in gout patients with metabolic syndrome (9.13 ± 3.15 mg/dL) than in gout patients without metabolic syndrome (8.14 ± 2.07 mg/dL). The mean SUA level was also significantly higher in patients with gout and CKD (9.55 ± 2.86 mg/dL) than in patients with gout but no CKD (7.74 ± 2.27 mg/dL). In gout patients, HOMA-IR was positively correlated with waist circumference (r = 0.409, p = 0.001).

CONCLUSIONS

The prevalence of metabolic syndrome in patients with gout was 50.8%, which is higher than the prevalence in the general Korean population. Hyperuricemia in gout patients was correlated with metabolic syndrome and CKD. Insulin resistance may provide clues to better understand the relationship between metabolic syndrome, CKD, and gout.

Visceral fat obesity is highly associated with primary gout in a metabolically obese but normal weighted population: a case control study

Introduction

Gout is a chronic inflammatory disease the development of which is associated with obesity-induced metabolic abnormalities. However, a substantial number of non-obese patients (body mass index [BMI] <25 kg/m²) also develop gout in Korea. It was suggested that accumulation of visceral fat rather than subcutaneous fat is associated with metabolic abnormalities and hyperuricemia in patients with gout; therefore, we hypothesized that visceral fat accumulation was increased in non-obese gout patients.

Methods

One hundred and three male patients with primary gout and 204 age-matched healthy controls who attended a health check-up examination were recruited after the review of medical charts. The visceral fat area (VFA) was measured using the bioelectrical impedance analysis (BIA) method, and a VFA >100 cm² was defined as visceral fat obesity (VFO). The frequency of VFO was compared in patients and control groups. The frequencies of metabolic syndrome and related parameters were also investigated.

Results

BMI, waist circumference, total fat mass, serum triglycerides, and serum glucose levels were significantly greater in patients compared with controls. VFA and the prevalence of VFO was increased in gout patients compared with controls. There were positive correlations between VFA and serum triglyceride levels and serum glucose levels. Multivariate regression analysis revealed that VFO is an independent risk factor for gout (odds ratio 2.488, 95% confidence interval 1.041–4.435). In non-obese subgroup analyses (gout patients, n = 38; healthy controls, n = 150), VFA (98.7 ± 19.3 vs. 91.0 ± 16.7, P = 0.016) and the frequency of VFO (47.4 vs. 27.3%, P = 0.017) remained significantly higher in gout patients. There was no difference in either BMI or total fat mass between patients and controls in the non-obese subgroup. The prevalence of metabolic syndrome in patients with gout was 31.7% (33/104), compared with 13.2% (5/38) in the non-obese subgroup according to modified ATP III criteria.

Conclusion

VFO, measured using BIA, is observed more frequently in patients with primary gout compared with healthy controls, even in non-obese individuals. Therefore, VFO might more properly represent metabolic derangements in patients with gout than general obesity.

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.

Clinical utility of dual-energy CT for evaluation of tophaceous gout

Although diagnosing gout generally is straightforward, atypical disease may present a challenge if it is associated with unusual symptoms or sites, discordant serum urate level, or mimics of gout. Dual-energy computed tomography (CT) may be used to differentiate urate crystals from calcium by using specific attenuation characteristics, which may help diagnose gout. In patients with known tophaceous gout, dual-energy CT may be used for serial volumetric quantification of subclinical tophi to evaluate response to treatment. Given the utility of dual-energy CT in challenging cases and its ability to provide an objective outcomes measure in patients with tophaceous gout, dual-energy CT promises to be a unique and clinically relevant modality in the diagnosis and management of gout.

Is there anything good in uric acid?

High uric acid (UA) levels can cause gout, urolithiasis and acute and chronic nephropathy, all of which are due to the deposit of urate crystals. There is also increasing evidence of relationships of hyperuricemia with other important disorders, including hypertension, chronic renal disease, metabolic syndrome and cardiovascular disease, as well as an increased mortality, although a causal relationship between these conditions has not been clearly established. On the other hand, low UA levels are not known to cause any disorder or disease. However, in the last few years a higher prevalence and progression of some neurological diseases have been associated with a low UA, and it is possible that they may predispose to some other disorders, mainly due to the decrease in its antioxidant activity. In this article, the known negative effects of UA are reviewed, as well as the much less-known possible positive actions, and their therapeutic implications.