Serum Uric Acid in Chronic Obstructive Pulmonary Disease: A Hospital Based Case Control Study

Identification of Oxidative Stress-Associated Biomarkers in Chronic Obstructive Pulmonary Disease: An Integrated Bioinformatics Analysis

Purpose

Chronic obstructive pulmonary disease (COPD) is among the three leading causes of death worldwide, with its prevalence, morbidity, and mortality rates increasing annually. Oxidative stress (OS) is a key mechanism in COPD development, making the identification of OS-related biomarkers beneficial for improving its diagnosis and treatment.

Methods

The genetic data from patients with COPD and controls were obtained from the Gene Expression Omnibus database to identify OS-related genes (OSRGs). Functional enrichment analysis was conducted using the Kyoto encyclopedia of genes and genomes signaling pathway and gene ontology (GO). Protein-protein interaction networks were constructed to identify the core genes, which were further evaluated using receiver operating characteristic (ROC) curves. Diagnostic models were developed based on the core genes. Besides, the correlation between the expression of the core genes and the immune cells was analyzed using single-sample gene set enrichment analysis. Drug-gene interactions were explored to predict target drugs, and related microribonucleic acid (miRNA) and transcription factors (TFs) were identified using miRNet.

Results

In this study, we identified 299 differential genes, including 16 OSRGs. Among these, five core genes-heat shock protein family A (Hsp70) member 1A (HSPA1A), glutamate-cysteine ligase modifier subunit, interleukin-1 beta (IL-1β), intercellular adhesion molecule 1 (ICAM1), and glutamate-cysteine ligase catalytic subunit (GCLC)-were screened and validated using ROC curve analysis. The results of GO enrichment analysis were mainly focused on the OS response, the negative regulation of the exogenous apoptosis signaling pathway, and the regulation of the apoptosis signaling pathway. Additionally, 33 target drugs were predicted, including ofloxacin, cisplatin, and pegolimumab, among others. Meanwhile, the regulatory networks comprising 33 miRNAs related to the core genes and 38 TFs associated with HSPA1A, IL-1β, ICAM1, and GCLC were constructed. A diagnostic model based on the five genes was constructed and validated with an area under the curve of 0.981 (95% confidence interval: 0.941-1.000).

Conclusion

This study identifies potential biomarkers for diagnosing COPD, new potential targets, and new directions for drug development and treatment.

Correlation between serum bilirubin, blood uric acid, and C-reactive protein and the severity of chronic obstructive pulmonary disease

OBJECTIVE

To explore the correlation between serum bilirubin, blood uric acid, and C-reactive protein (CRP) and the severity of chronic obstructive pulmonary disease (COPD).

METHODS

Patients with COPD who were admitted to our hospital between March 2020 and March 2023 were retrospectively studied. Based on whether their condition progressed to the acute exacerbation stage, they were divided into an exacerbation group (100 cases) and a stability group (100 cases). The clinical data from both groups were analysed to assess the correlations between serum bilirubin, blood uric acid, CRP, and the severity of COPD.

RESULTS

Univariate analysis indicated significant differences in the neutrophil-to-lymphocyte ratio (t = 5.678, P < 0.05), α-hydroxybutyrate dehydrogenase (t = 5.862, P < 0.05), total bilirubin (t = 4.341, P < 0.05), direct bilirubin (t = 5.342, P < 0.05), indirect bilirubin (t = 5.452, P < 0.05), blood uric acid (t = 4.698, P < 0.05), and CRP (t = 4.892, P < 0.05) between the two groups. Multivariate analysis revealed that total bilirubin, blood uric acid, and CRP were positively correlated with exacerbations of COPD (regression coefficients were 0.413, 0.354, and 0.356, respectively; P < 0.05). The evaluation of predictive value showed that the combined predictive value of these three indicators was the highest, with an AUC of 0.823 (95% CI: 0.754-0.911).

CONCLUSION

Serum bilirubin, blood uric acid, and CRP levels are elevated in patients with acute exacerbations of COPD (AECOPD), showing good consistency in predicting the occurrence of AECOPD. The combined diagnostic value of these three indicators is greater than that of any single indicator, providing a reference for the early clinical prediction of AECOPD.

Large-scale cross-ancestry genome-wide meta-analysis of serum urate

Hyperuricemia is an essential causal risk factor for gout and is associated with cardiometabolic diseases. Given the limited contribution of East Asian ancestry to genome-wide association studies of serum urate, the genetic architecture of serum urate requires exploration. A large-scale cross-ancestry genome-wide association meta-analysis of 1,029,323 individuals and ancestry-specific meta-analysis identifies a total of 351 loci, including 17 previously unreported loci. The genetic architecture of serum urate control is similar between European and East Asian populations. A transcriptome-wide association study, enrichment analysis, and colocalization analysis in relevant tissues identify candidate serum urate-associated genes, including CTBP1, SKIV2L, and WWP2. A phenome-wide association study using polygenic risk scores identifies serum urate-correlated diseases including heart failure and hypertension. Mendelian randomization and mediation analyses show that serum urate-associated genes might have a causal relationship with serum urate-correlated diseases via mediation effects. This study elucidates our understanding of the genetic architecture of serum urate control.

Robust positive association between serum urate and the risk of chronic obstructive pulmonary disease: hospital-based cohort and Mendelian randomisation study

BACKGROUND

Chronic obstructive pulmonary disease (COPD) and hyperuricaemia are both characterised by systemic inflammation. Preventing chronic diseases among the population with common metabolic abnormality is an effective strategy. However, the association of hyperuricaemia with the higher incidence and risk of COPD remains controversial. Therefore, replicated researches in populations with distinct characteristics or demographics are compellingly warranted.

METHODS

This cohort study adopted a design of ambispective hospital-based cohort. We used propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) to minimise the effects of potential confounding factors. A Cox regression model and restricted cubic spline (RCS) model were applied further to assess the effect of serum urate on the risk of developing COPD. Finally, we conducted a two-sample Mendelian randomisation (MR) analysis to explore evidence of causal association.

RESULTS

There is a higher incidence in the population with hyperuricaemia compared with the population with normal serum urate (22.29/1000 person-years vs 8.89/1000 person-years, p=0.009). This result is robust after performing PSM (p=0.013) and IPTW (p<0.001). The Cox model confirms that hyperuricaemia is associated with higher risk of developing COPD (adjusted HR=3.35 and 95% CI=1.61 to 6.96). Moreover, RCS shows that the risk of developing COPD rapidly increases with the concentration of serum urate when it is higher than the reference (420 µmol/L). Finally, in MR analysis, the inverse variance weighted method evidences that a significant causal effect of serum urate on COPD (OR=1.153, 95% CI=1.034 to 1.289) is likely to be true. The finding of MR is robust in the repeated analysis using different methods and sensitivity analysis.

CONCLUSIONS

Our study provides convincing evidence suggesting a robust positive association between serum urate and the risk of developing COPD, and indicates that the population with hyperuricaemia is at high risk of COPD in the Chinese population who seek medical advice or treatment in the hospital.

The Relationship between Serum Uric Acid Levels and Early Mortality in Chronic Obstructive Pulmonary Disease Cases during Exacerbation

AIM

In this study, it was aimed to compare the levels of serum uric acid and uric acid/creatinine ratios in patients with COPD during an attack or in stable COPD, and to show whether serum uric acid and uric acid/creatinine ratios are associated with early mortality in COPD patients during an acute attack.

MATERIALS AND METHODS

In this study, COPD acute attack (n=155) and stable COPD (n=30) patients were evaluated. The data of these patients were obtained from patient files and computer records. COPD diagnosis and severity assessment were made according to the GOLD 2006 guideline. Participants' age, gender, body mass index, pulmonary function test, arterial blood gas, uric acid, creatinine values and comorbidity information were recorded in the previously prepared Case Data Form. In 2012, when we conducted this study, gold 2006 was taken as the guideline for spirometry measurement, but spirometric measurements determined with reference values determined according to age, height and gender, and FEV1/FVC measurement <70% as diagnostic criteria in acute attack after bronchodilator were the guidelines used later, gold 2017. It is also compatible with gold2020 and gold2021 spirometry criteria.

RESULTS

It was determined that the uric acid (p<0.001) and uric acid/creatinine (p<0.001) levels of the patients in the acute attack group were significantly higher than the levels of the patients in the stable group. The attack group was divided into two subgroups according to certain cut-off points for uric acid (>6 mg/dl for women and >7 mg/dl for men) and uric acid/creatinine ratio (median value 7.10). Since the upper limit of the uric acid value measured in the blood is 6 mg/dl in women and 7-8 mg/dl in men, the cut-off points for uric acid (>6 mg/dl for women and >7 mg/dl for men) were determined in our study. According to this categorization, it was determined that there was no statistically significant relationship between uric acid level (odds ratio 2.985 [95% confidence interval 0.61814,151]) and early mortality risk.

CONCLUSION

The results of this study showed that the uric acid and uric acid/creatinine levels in the attack group were higher than the levels in the stable group, but these parameters were not associated with early mortality.

Gender-Specific Association of Serum Uric Acid and Pulmonary Function: Data from the Korea National Health and Nutrition Examination Survey

Background and Objectives: Hyperuricemia is associated with several comorbidities. The association between uric acid (UA) and pulmonary function is still a controversial issue. This study evaluated the gender-specific association of serum UA and pulmonary function. Materials and Methods: A total of 3177 (weighted n = 19,770,902) participants aged 40 years or older were selected from the 2016 Korean National Health and Nutrition Examination Survey and included. Results: Female participants with hyperuricemia were older than participants with normouricemia. Body mass index (BMI), mean arterial pressure (MAP), hemoglobin A1c (HbA1c), and estimated glomerular filtration rate (eGFR) were significantly associated with UA levels in both males and females. Hyperuricemia and increase in UA quartile were significantly associated with decreased forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) in females after adjustment for age, income, region, education, marital status, alcohol consumption, smoking, BMI, MAP, HbA1c, and eGFR. There was no significant association between UA levels and lung function in males. After additional adjustment for respiratory disease including pulmonary tuberculosis, asthma, and lung cancer, the association between hyperuricemia and decreased FEV1 and FVC in females was revealed. Conclusions: Hyperuricemia was associated with decreased FVE1 and FVC in the female general population.

Serum uric acid level as a biomarker for chronic obstructive pulmonary disease: a meta-analysis

OBJECTIVE

To determine if there is a relationship between the levels of serum uric acid and the different Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages (1-4) classified by the severity of the airflow limitation in patients with stable chronic obstructive pulmonary disease (COPD).

METHODS

Electronic databases, including PubMed®, Embase®, Web of Science™ and China National Knowledge Infrastructure (CNKI), were searched from inception to December 2018. Observational studies that reported serum uric acid levels in stable COPD patients were included. Two investigators independently extracted data and RevMan version 5.3 was used to carry out the statistical analyses.

RESULTS

Seven studies with 932 stable COPD patients and 401 healthy control subjects were included in this meta-analysis. Serum uric acid levels were significantly higher in stable COPD patients compared with healthy control subjects (mean difference [MD] 1.91, 95% confidence interval [CI] 1.55, 2.28). Serum uric acid levels were significantly lower in the GOLD 1+2 subgroup compared with the GOLD 3+4 subgroup (MD -1.39, 95% CI -1.63, -1.15).

CONCLUSION

Serum uric acid might be a useful biomarker for identifying disease severity in stable COPD patients, but further studies are needed to confirm this finding.

Hypouricemia and Mortality Risk in the US General Population

OBJECTIVE

The most recent European Alliance of Associations for Rheumatology (EULAR) recommendations for gout advise against maintaining a serum urate (SU) level of <3 mg/dl for prolonged periods of time. While several Asian cohort studies have shown higher rates of mortality in individuals with extremely low SU levels, data from non-Asian cohort studies are scarce, and the relationship between hypouricemia, cardiovascular risk, and mortality remains unclear.

METHODS

Using data collected from the 1988-1994 and 1999-2008 National Health and Nutrition Examination Survey (NHANES), we examined the relationship between SU level and overall and cause-specific mortality in 41,807 adults in the US. We calculated multivariable hazard ratios (HRs) that were compared to a referent SU level of 5-6 mg/dl for SU categories <4, 4-5, 6-7, 7-8, and >8 mg/dl in men and SU categories <3, 3-4, 4-5, 6-7, and >7 mg/dl in women.

RESULTS

A higher mortality risk was not observed in women who had an SU level of <3 mg/dl (HR 1.09 [95% confidence interval (95% CI) 0.92-1.28]). A 28% higher mortality risk was observed in men who had an SU level of <4 mg/dl (HR 1.28 [95% CI 1.13-1.45]), with a nearly three-times higher mortality risk from diabetes mellitus also noted (HR 2.89 [95% CI 1.59-5.23]), but no increase in mortality from any other specific cause.

CONCLUSION

We found no long-term excess mortality risk among American women with SU levels as low as <3 mg/dl, a finding which is incompatible with the notion of a causal relationship between hypouricemia and premature mortality in women. We found excess all-cause mortality and diabetes mellitus-related mortality among hypouricemic American men, which may in part be attributable to the uricosuric effect of hyperglycemia in fatal uncontrolled diabetes mellitus (analogous to reverse causality).

Uric acid and uric acid to creatinine ratio in the assessment of chronic obstructive pulmonary disease: Potential biomarkers in multicomponent models comprising IL-1beta

Chronic obstructive pulmonary disease (COPD) is a complex and heterogeneous disease, with oxidative stress and inflammation implicated in its development. Uric acid (UA) could exert anti-oxidative, pro-oxidative or pro-inflammatory effects, depending on the specific context. It was recently shown that soluble UA, and not just its crystals, could activate the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, leading to interleukin (IL)-1β secretion. We aimed to assess the differences in blood levels of UA and its ratio with creatinine (UCR) between COPD patients and healthy subjects, as well as their association with disease severity, smoking status, common COPD comorbidities and therapy regimes. The diagnostic characteristics of UA and UCR were also explored. This study included 109 stable COPD patients and 95 controls and measured white blood cells (WBC), C-reactive protein (CRP), fibrinogen (Fbg), IL-1β, creatinine (CREAT) and UA. All of the parameters were increased in COPD patients, except for CREAT. UA and UCR were positively associated with WBC, CRP and IL-1β. COPD smokers had lower UA and UCR values. Common COPD therapy did not affect UA or UCR, while patients with cardiovascular diseases (CVD) had higher UA, but not UCR, levels. Patients with higher UCR values showed worse disease-related outcomes (lung function, symptoms, quality of life, history of exacerbations, BODCAT and BODEx). Also, UCR differentiated patients with different severity of airflow limitation as well as symptoms and exacerbations. The great individual predictive potential of UCR and IL-1β was observed with their odds ratios (OR) being 2.09 and 5.53, respectively. Multiparameter models of UA and UCR that included IL-1β were able to correctly classify 86% and 90% of cases, respectively. We suggest that UA might be a useful biomarker when combined with IL-1β, while UCR might be even more informative and useful in overall COPD assessments.