A combination of red and processed meat intake and polygenic risk score influences the incidence of hyperuricemia in middle-aged Korean adults

BACKGROUND/OBJECTIVES

The high consumption of purine-rich meat is associated with hyperuricemia. However, there is limited evidence linking the consumption of red and processed meat to the genetic risk of hyperuricemia. We investigated the relationship between various combinations of red and processed meat consumption and the polygenic risk scores (PRSs) and the incidence of hyperuricemia in middle-aged Koreans.

SUBJECTS/METHODS

We analyzed the data from 44,053 participants aged ≥40 years sourced from the Health Examinees (HEXA) cohort of the Korean Genome and Epidemiology Study (KoGES). Information regarding red and processed meat intake was obtained using a semiquantitative food frequency questionnaire (SQ-FFQ). We identified 69 independent single-nucleotide polymorphisms (SNPs) at uric acid-related loci using genome-wide association studies (GWASs) and clumping analyses. The individual PRS, which is the weighted sum of the effect size of each allele at the SNP, was calculated. We used multivariable Cox proportional hazards models adjusted for covariates to determine the relationship between red and processed meat intake and the PRS in the incidence of hyperuricemia.

RESULTS

During an average follow-up period of 5 years, 2,556 patients with hyperuricemia were identified. For both men and women, the group with the highest red and processed meat intake and the highest PRS was positively associated with the development of hyperuricemia when compared with the group with the lowest red and processed meat intake and the lowest PRS (hazard ratio [HR], 2.72; 95% confidence interval [CI], 2.10-3.53; P < 0.0001; HR, 3.28; 95% CI, 2.45-4.40; P < 0.0001).

CONCLUSION

Individuals at a high genetic risk for uric acid levels should moderate their consumption of red and processed meat to prevent hyperuricemia.

Epidemiology and treatment-related concerns of gout and hyperuricemia in Korean

Gout is the most common form of inflammatory arthritis that affects mainly middle-aged men, and there is clear evidence of an association between hyperuricemia and the risk for gout. Increasing prevalence of gout and hyperuricemia has been reported in many countries. The prevalence of gout and hyperuricemia are constantly increasing in Korea with the patients at risk for developing a variety of comorbidities. Although there have been studies on the association between gout or serum uric acid level and several neurodegenerative diseases, cancer, and cardiovascular mortality, the causal relationship between gout and these comorbidities are still unclear. The associations of substantial economic burden with hyperuricemia, gout attack, and suboptimal treatment are well known. Gout is a disease that requires lifelong management including lifestyle modification. However, gout is poorly managed worldwide although effective urate-lowering drugs exist. In this review, we addressed epidemiological studies and treatment-related problems in the Korean population with gout or hyperuricemia to obtain the best clinical outcomes and reduce their medical burden.

Clinical Study Using Healthcare Claims Database

The healthcare claims database is a database created using claims data accumulated while operating the government's health insurance system. The National Health Insurance Service (NHIS) provides benefits for health promotion, prevention, diagnosis, and disease and injury treatment, as well as for rehabilitation, birth, and death. Ninety-seven percent of the total population is enrolled in the NHIS; individuals pay a monthly insurance contribution to the system, and the NHIS pays a portion of the cost of reimbursement items to the medical institution when the subscriber receives medical services. In this process, the NHIS and Health Insurance Review Agency (HIRA) decide on payment, and claims data are documented items that medical institutions claim to these government agencies. The NHIS and HIRA have established a database to support policy and academic research, and they provide this database to researchers. Health claims data are representative of the nation, reflecting the actual medical environment. They also shorten the time and cost required for research and have several advantages as research data. However, studies should be conducted with an understanding of the limitations of claims data, a sufficient understanding of the characteristics of the Korean insurance system, and criteria for providing reimbursed services. Moreover, validating the healthcare claims database will facilitate more useful and reliable research.

Clinical features and risk factors for gout attacks during anti-tuberculosis treatment: A case-control study in South Korea

AIM

This study aimed to investigate the clinical features and risk factors of gout attacks during anti-tuberculosis (TB) treatment in South Korea.

METHOD

We investigated the clinical characteristics of 49 patients who suffered from gout attacks while taking anti-TB medications. Among them, 25 TB patients having newly developed gout attacks without prior history of gout were set to the gout group. Seventy-five age- and sex-matched TB patients without gout attacks during anti-TB therapy were randomly selected as the control group. The demographics, clinical features, and laboratory findings between the two groups were compared to establish risk factors of gout attack during anti-TB treatment.

RESULTS

The gout patients had a mean age of 67.7 ± 13.2 years and 39 patients (79.6%) were male. Approximately half of the patients experienced an attack within 2 months of treatment initiation. The attacks typically involved lower extremity joints (87.8%). The serum uric acid (SUA) levels were significantly elevated at 2 and 6 months after starting anti-TB medication compared with those at baseline. In the case-control study, the factors associated with gout attack were higher body mass index (BMI), higher pre-treatment SUA levels, dyslipidemia, and reduced renal function. In the multivariate model, higher BMI, chronic kidney disease (CKD), and pre-treatment hyperuricemia (SUA ≥ 6.8 mg/dL) were independent risk factors of gout attack while taking anti-TB medication.

CONCLUSIONS

Patients with high BMI, CKD, and pre-treatment hyperuricemia are at a higher risk of gout attack during TB treatment.

Women with Metabolic Syndrome and General Obesity Are at a Higher Risk for Significant Hyperuricemia Compared to Men

Hyperuricemia is an emerging potential biomarker for metabolic syndrome (MetS) and its complications. This study aimed to investigate the risk factors of hyperuricemia, particularly, the association of hyperuricemia with MetS and general obesity according to sex. We performed multivariate logistic regression analyses using the 2016 Korean National Health and Nutrition Examination Survey data. Hyperuricemia was defined by a serum uric acid level ≥7.0 mg/dL for men and ≥6.0 mg/dL for women. General obesity was based on a body mass index (BMI) ≥25 kg/m². Among a total of 5591 Korean adult participants, 685 (12.3%) individuals had hyperuricemia. Hyperuricemia was significantly associated with MetS in men (odds ratio (OR): 2.38, 95% CI: 1.84–3.08) and in women (OR: 4.15, 95% CI: 2.75–6.28) after adjustments. General obesity was also independently related to hyperuricemia in both sexes (OR: 2.17, 95% CI: 1.76–2.68 in men, OR: 3.80, 95% CI: 2.82–5.12 in women). In subgroup analyses, the presence of concomitant MetS and general obesity posed a strikingly higher risk for hyperuricemia among women (OR: 7.24, 95% CI: 4.56–11.50) when compared to men (OR: 2.90, 95% CI: 2.12–3.96). More attention should be paid to the increased risk of hyperuricemia for females with both MetS and general obesity.

Synergic effect in the reduction of serum uric acid level between ethanol extract of Aster glehni and vitamin B6

In this study, synergistic hypoudpricemic activities between ethanol extract of Aster glehni (AG) and vitamin B₆ were investigated in vitro and in vivo. Xanthine oxidase inhibitory activities in the different parts, leaf, stem, and flower, during spring and autumn were compared. In addition, to improve hypouricemic activity, two chemicals (AG extract and vitamins) were mixed and measured inhibitory activity of xanthine oxidase. As a result, autumn leaf AG extracts showed the most effective xanthine oxidase inhibitory activity and we named autumn leaf AG extracts as AG-D006. In synergistic study, AG-D006 with vitamin B₆ showed significantly increased inhibitory activity on xanthine oxidase. AG-D006 with vitamin B₆ also showed significantly reduced uric acid level in hyperuricemic rats in vivo. In conclusion, AG-D006 with vitamin B₆ might be used functional foods in reducing serum uric acid level in gout.

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.

Prevalence and incidence of gout in Korea: data from the national health claims database 2007-2015

The purpose of the present study was to investigate the prevalence and incidence of gout in Korea and predict the future prevalence and incidence of gout. Data were collected from the national health claims database. Patients who had at least one claim for gout between 2007 and 2015 were included in the study. The prevalence of gout from 2007 to 2015 and the incidence of gout from 2009 to 2015 were determined. We estimated sex- and age-specific prevalence and incidence of gout during the period. The prevalence and incidence of gout were predicted using time series analysis. The prevalence of gout (95% CI) increased from 3.49 (3.48-3.51) per 1000 persons in 2007 to 7.58 (7.55-7.60) per 1000 persons in 2015. The incidence of gout (95% CI) was 1.52 (1.51-1.53) in 2009 and rose to 1.94 (1.93-1.95) per 1000 persons in 2015. The prevalence and incidence of gout were higher in men than in women. The older population had a higher prevalence and incidence than the younger population. The increase in prevalence was higher in the older population than the younger population, whereas the increase in incidence was higher in the younger population than the older population. The predicted prevalence and incidence of gout (95% CI) in 2025 were 16.59 (15.85-17.34) per 1000 persons and 3.81 (3.14-4.47) per 1000 persons. The prevalence and incidence of gout increased in Korea between 2007 and 2015. Men and the older population had a higher prevalence and incidence of gout compared to women and the younger population. However, the incidence of gout in the younger population has increased rapidly in recent years.

Clinical factors and treatment outcomes associated with failure in the detection of urate crystal in patients with acute gouty arthritis

BACKGROUND/AIMS

To investigate the rate of detection of monosodium urate (MSU) crystals in the synovial fluid (SF) of patients with acute gouty arthritis and factors associated with false-negative results.

METHODS

A total of 179 patients with acute gouty arthritis who had undergone SF crystal examination were identified from the data warehouse of two university hospitals. Clinical and laboratory data were obtained from the medical records.

RESULTS

The overall rate of detection of MSU crystals was 78.8%. In univariate analyses, the only significant differences between the variables of crystal-negative and crystal-positive patients were a lower C-reactive protein level (p = 0.040) and fewer patients undergoing emergent surgery in the crystal-positive group (p = 4.5 × 10(-6)). In logistic regression analyses, MSU crystal-negative results were significantly associated with the interval from arthritis onset to crystal examination (p = 0.042), and this was the most significant risk factor for arthroscopic surgery (p = 2.1 × 10(-4)). Seventeen patients who underwent arthroscopic surgery had a significantly longer hospital stay (p = 0.007) and a significant delay in gout treatment (p = 8.74 × 10(-5)). The distribution of crystal-negative patients differed significantly between the SF samples that were evaluated by both the laboratory medicine and the rheumatology departments (p = 1.2 × 10(-14)), and the κ value was 0.108.

CONCLUSIONS

Although several clinical features were associated with detection failure, SF MSU crystal identification was critically dependent on the observer. Considering the impact on the treatment outcomes, implementation of a quality control program is essential.

The frequency of single nucleotide polymorphisms and their association with uric acid concentration based on data from genome-wide association studies in the Korean population

We aimed, first, to investigate the minor allele frequencies (MAFs) of single nucleotide polymorphisms (SNPs) associated with serum uric acid (SUA) level in the Korean population and compare these with data from other ethnic groups and, second, to investigate whether the SNPs are associated with altered SUA levels. We examined the frequencies of risk alleles, investigated the MAFs of 40 previously described SNPs associated with SUA level in the Korean population (a total of 1,957 subjects), and compared results with data for other ethnic groups. We also analyzed associations with SUA concentrations based on data from genome-wide association studies in the Korean population (a total of 402 rheumatoid arthritis subjects) and tested whether polymorphism of any of the 40 SNPs associated with SUA identified previously was associated with SUA levels. The MAFs of SNPs associated with SUA level in the Korean population were quite similar to those among Japanese, but not in populations of European descent. SNP rs12734001 (PPP1R12B) proved to have the most probable association with SUA concentrations (P_trend = 2.29 × 10(-9)). We also analyzed 13 SNPs shown previously by meta-analysis to be associated with SUA, and SNP rs3741414 (INHBC) was found to have probable association with SUA level observed in the present study (P_trend = 0.01). The pattern of variants controlling SUA levels in the Korean population is not similar to that in European population. SNP rs12734001 (PPP1R12B) is significantly associated with SUA level among Koreans.