Uric acid as a potential mediator of cardiovascular morbidity in obstructive sleep apnea syndrome

Clinical outcomes of obstructive sleep apnea in patients with acute coronary syndrome in relation to hyperuricemia status

The clinical outcome of obstructive sleep apnea in patients with acute coronary syndrome in relation to hyperuricemia is still unclear. We aimed to explore the clinical prognosis of obstructive sleep apnea in patients with acute coronary syndrome in relation to hyperuricemia status. This was a prospective cohort study. We included consecutively eligible patients with acute coronary syndrome who underwent cardiorespiratory polygraphy between June 2015 and January 2020. According to apnea-hypopnea index ≥ 15 events per hr and serum uric acid level, the population was divided into four groups: hyperuricemia with obstructive sleep apnea; hyperuricemia with non-obstructive sleep apnea; no hyperuricemia with obstructive sleep apnea; and no hyperuricemia with non-obstructive sleep apnea. The primary endpoint was major adverse cardiovascular and cerebrovascular events, including cardiovascular death, myocardial infarction, stroke, ischaemia-driven revascularization, and readmission for unstable angina or heart failure. Spearman correlation analysis and Cox regression model were mainly used to estimate the data. The median follow-up was 2.9 years. Among 1925 patients with acute coronary syndrome, 29.6% had hyperuricemia and 52.6% had obstructive sleep apnea. Uric acid was negatively correlated with minimum arterial oxygen saturation and mean arterial oxygen saturation, and positively correlated with apnea-hypopnea index, oxygen desaturation index and the duration of time with arterial oxygen saturation < 90% (p < 0.001). During 2.9 (1.5, 3.6) years of follow-up, obstructive sleep apnea was associated with an increased risk of major adverse cardiovascular and cerebrovascular events in patients with hyperuricemia (23.5% versus 13.4%; adjusted hazard ratio: 1.834; 95% confidence interval: 1.192-2.821, p = 0.006), but not in patients without hyperuricemia (21.9% versus 19.2%; adjusted hazard ratio: 1.131; 95% confidence interval: 0.880-1.453, p = 0.336). There was a correlation between uric acid levels and sleep respiratory indicators. Obstructive sleep apnea was associated with increased risk of major adverse cardiovascular and cerebrovascular events in patients with acute coronary syndrome with hyperuricemia, but not in patients without hyperuricemia.

Association between obstructive sleep apnea symptoms and gout in US population, a cross-sectional study

The results of association between Obstructive Sleep Apnea (OSA) and gout are not consistent. Participants aged 20 years or older in the National Health and Nutrition Examination Survey (NHANES) 2007-2008 and 2015-2018 were included. Weighted univariable and multivariable logistic regressions were used to evaluate the association between OSA symptoms and gout. The subgroup and sensitivity analyses were also performed. Among the 15,947 participants in this study, the mean age was 47.8 years old, 48.87% of whom were male, 4891 had OSA symptoms, and 842 had gout. In multivariable logistic regression analyses, OSA symptoms were positively associated with gout in all models. The odds ratio (OR) was 1.315 and 95% confidence interval (CI) was 1.070-1.616 in fully adjusted model 4. In the subgroup analyses, we found a considerable interaction between OSA symptoms and gender with gout (P for interaction = 0.003). In the sensitivity analyses, the association between OSA symptoms and gout remained stable after adjustment for congestive heart failure and diuretics using. OSA symptoms were associated with an increased likelihood of gout. This association could especially be found in female participants.

Assessing the causal associations of obstructive sleep apnea with serum uric acid levels and gout: a bidirectional two-sample Mendelian randomization study

OBJECTIVE

Multiple observational studies have reported the close associations of obstructive sleep apnea (OSA) with serum uric acid (SUA) levels and gout. However, the causal nature and direction remains unclear.

METHODS

A bidirectional two-sample Mendelian randomization (MR) study was performed, based on publicly available genome-wide association studies (GWAS) summary statistics, to investigate whether OSA is causally related to SUA levels, gout and vice versa. The inverse-variance weighted (IVW) was used as the primary analysis approach, supplemented with four sensitive analysis methods applied to assess the robustness of the results. Moreover, multivariable MR (MVMR) was utilized to evaluate the independent causal effect of OSA on SUA and gout after adjusting for body mass index (BMI), hypertension, type 2 diabetes (T2D), coronary artery disease (CAD), and chronic kidney disease (CKD).

RESULTS

Genetically predicted OSA liability was significantly associated with increased levels of SUA (IVW method: β = 0.19, 95% CI = 0.11 - 0.26, P = 7.24 × 10^-7) and risk of gout [IVW method: odds ratio (OR) = 1.75 95% CI = 1.13 - 2.69, P = 0.01] in univariable MR. The MVMR results suggested that OSA retained its significant association with increased SUA levels, whereas the significant association between OSA and gout was attenuated to null after adjusting for BMI and T2D. No causal effect of OSA on SUA levels and gout was found in the reverse direction.

CONCLUSIONS

Our findings suggest that OSA was causally associated with increased levels of SUA, but was not independently associated with gout risk.

Assessment of hypertension in obstructive sleep apnea by ambulatory blood pressure monitoring: a systematic review and meta-analysis

Among obstructive sleep apnea (OSA) patients, there exists a high prevalence of hypertension. Determining the optimal blood pressure (BP) monitoring modality in this population will lead to a better understanding of hypertension profiles and a more accurate diagnosis of hypertension. PubMed, Ovid/Medline, Web of Science, Scopus, Cochrane Library, and CINAHL databases were screened, and the relevant articles regarding BP monitoring in OSA patient population were selected. Studies evaluating both ambulatory (ABPM) and office BP measurements were selected to be analyzed for the hypertension diagnosis specificity of ABPM measurement in OSA patients compared with office measurements. If reported, additional information regarding white-coat, masked hypertension, and circadian BP pattern prevalence was included. A cumulative analysis of five studies revealed a prevalence of hypertension based on BP to be 44%, whereas a cumulative analysis of four studies revealed a prevalence of hypertension based on ABPM to be 66%. Excluding a study with the nighttime assessment of hypertension reduced the cumulative prevalence of hypertension in OSA patients to 59%. The cumulative prevalence of Studies demonstrated the prevalence of masked and white-coat hypertension to be 34 and 9%, respectively. As a higher prevalence of hypertension was detected by ABPM and nighttime measurement, it can be deduced that ABPM is more sensitive in determining OSA patients with hypertension, and that nighttime ABPM further increases this sensitivity. The presence of masked and white-coat hypertension in OSA patients underlines the importance of correct hypertension diagnosis as it affects further management in this population with increased cardiovascular risk.

Snoring and napping independently increased the serum uric acid levels and hyperuricemia risk: The Henan Rural Cohort Study

BACKGROUND AND AIMS

Evidence on the association of snoring, daily sleep duration (daytime napping and night sleep duration) with hyperuricemia (HUA) was limited, especially in the resources-poor areas. This study aimed to investigate the independent effect of snoring frequency and daily sleep duration on HUA prevalence in rural Chinese adults.

METHODS AND RESULTS

29,643 participants aged 18-79 years were included in the final cross-sectional analysis from the Henan Rural Cohort Study. Multivariate logistic regression and linear regression models with HUA and serum uric acid (SUA) levels as dependent variables were conducted, respectively. Of the 29,643 included adults, 3498 suffered from HUA. Compared to never snoring, the adjusted odds ratio (OR) and 95% confidence interval (CI) of HUA for rare snoring, occasional snoring, and habitual snoring were 1.35 (1.17, 1.56), 1.30 (1.14, 1.47), and 1.59 (1.47, 1.73), respectively (P for trend <0.001). Compared with no napping, participants who had daytime napping of 61-90 and > 91 min were associated with a 29% and 30% increase in the prevalence of HUA, respectively (P for trend <0.001). But in night sleep duration groups, no significant associations were observed. The positive associations between snoring and HUA were attenuated in people aged ≥65 and people with type 2 diabetes mellitus (both P for interaction <0.05).

CONCLUSION

Habitual snoring or longer daytime napping was independently associated with increased HUA prevalence and SUA levels in rural Chinese adults, which indicates the significance of early intervention and treatment of snoring and longer daytime napping to prevent hyperuricemia.

Increased Susceptibility of Atrial Fibrillation Induced by Hyperuricemia in Rats: Mechanisms and Implications

High levels of serum uric acid is closely associated with atrial fibrillation (AF); nonetheless, the detailed mechanisms remain unknown. Therefore, this work examined the intricate mechanisms of AF triggered by hyperuricemia and the impact of the uricosuric agent benzbromarone on atrial remodeling in hyperuricemic rats. After adjusting baseline serum uric acid levels, a total of 28 healthy male adult Sprague Dawley rats were randomly divided into 4 groups, namely, control (CTR), hyperuricemia (oxonic acid potassium salt, OXO) and benzbromarone (+ BBR), and OXO withdrawal groups. Primary rat cardiomyocytes were cultured with uric acid for 24 h to investigate the direct influence of uric acid on cardiomyocytes. Results revealed that AF vulnerability and AF duration were dramatically greater in hyperuricemic rats (OXO group), while the atrial effective refractory periods (AERPs) were significantly shorter. Meanwhile, BBR treatment and withdrawal of 2% OXO administration remarkably reduced AF inducibility and shortened AF duration. Moreover, abnormal morphology of atrial myocytes, atrial fibrosis, apoptosis, and substantial sympathetic nerve sprouting were observed in hyperuricemic rats. Apoptosis and fibrosis of atria were partly mediated by caspase-3, BAX, TGF-β1, and α-smooth muscle actin. Uric acid significantly induced primary rat cardiomyocyte apoptosis and fibrosis in vitro. Also, we found that sympathetic nerve sprouting was markedly upregulated in the atria of hyperuricemia rats, and was restored by BRB or absence of OXO administration. In summary, our study confirmed that AF induced by hyperuricemic rats occurred primarily via induction of atrial remodeling, thereby providing a novel potential treatment approach for hyperuricemia-related AF.

Serum uric acid and arterial lactate levels in patients with obstructive sleep apnea syndrome: the effect of CPAP treatment

Objectives: Serum uric acid (UA) and arterial lactate acid (LA) are markers of oxidative stress and tissue hypoxia that are present in patients with obstructive sleep apnea syndrome (OSAS). The aim of the study was to evaluate the associations between UA and LA levels and OSAS characteristics as well as the effect of their levels after continuous positive airway pressure (CPAP) treatment.Methods: This is a retrospective of newly diagnosed patients with OSAS. UA and LA levels were measured the night before the diagnostic sleep study, and 6 months after CPAP therapy.Results: We evaluated 604 individuals with OSAS and 98 controls (i.e. individuals without sleep-related breathing disorders). Baseline median (IQR) serum UA levels were higher in OSAS patients compared to controls; 7.0 (6.4, 8.1) mg/dL vs 6.3 (6.1, 6.4) mg/dL, respectively (p < 0.001). This difference remained significant, after adjustment of serum UA to creatinine ratio (UA/Cr) (p < 0.001). Patients with OSAS had higher LA levels at baseline compared to controls; 2.26 (2.25, 2.31) mmol/L vs 1.90 (1.87, 1.97) mmol/L, respectively (p < 0.001). Both UA and LA levels decreased significantly after CPAP treatment [median (IQR): 7.0 (6.4, 8.1) mg/dL vs 6.4 (6.2, 6.8) mg/dL, p < 0.001 and 2.26 (2.25, 2.31) mmol/L vs 2.08 (2.07, 2.31) mmol/L, p < 0.001]. Several sleep parameters were independent predictors of UA and LA levels.Conclusion: In OSAS patients increased serum UA and arterial LA levels are found. CPAP therapy resulted in significant reductions in levels of both biomarkers.

Chlorogenic acid supplementation ameliorates hyperuricemia, relieves renal inflammation, and modulates intestinal homeostasis

Hyperuricemia (HUA) is induced by abnormal purine metabolism and elevated serum uric acid (UA) concentrations, and it is often accompanied by inflammatory responses and intestinal disorders. This study aims to assess the protective effects of chlorogenic acid (CGA) on HUA in mice. CGA or allopurinol was given to mice with HUA induced by hypoxanthine and potassium oxonate. CGA lowered the levels of UA, blood urea nitrogen (BUN), creatinine (CR), AST, and ALT; inhibited xanthine oxidase (XOD) activity; and downregulated the mRNA expression of UA secretory proteins in HUA mice. Moreover, CGA significantly reduced serum lipopolysaccharides (LPS) levels and the mRNA expression of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, NOD-like receptor superfamily pyrin domain containing 3 (NLRP3), and caspase-1, and it inhibited the activation of the toll-like receptor 4/myeloid differentiation factor 88/nuclear factor kappa B (TLR4/MyD88/NF-κB) signaling pathway in the kidney, resulting in inflammation relief in HUA mice. In addition, CGA treatment increased the production of fecal short-chain fatty acids (SCFAs) in HUA mice. Additional investigations showed that CGA significantly lowered the mRNA expression of ileal IL-1β and IL-6, and it increased the mRNA expression of intestinal tight junction proteins (zonula occludens-1 (ZO-1) and occludin). Also, CGA increased the relative abundance of SCFA-producing bacteria, including Bacteroides, Prevotellaceae UGC-001, and Butyricimonas, and it reversed the purine metabolism and glutamate metabolism functions of gut microbiota. In conclusion, CGA may be a potential candidate for relieving the symptoms of HUA and regulating its associated inflammatory responses and intestinal homeostasis.

Uric acid as a marker of severity of obstructive sleep apnoea syndrome in older patients

OBJECTIVE

Uric acid has been shown to be related to the severity of obstructive sleep apnoea syndrome (OSAS) in adults. We assessed the role of uric acid in OSAS in a cohort of older patients.

METHODS

A total of 164 patients aged >65 years, admitted to our sleep laboratory between January 1st, 2016 and July 1st, 2018 with a complaint of snoring, underwent overnight polysomnography and were retrospectively evaluated.

RESULTS

A total of 126 patients who fulfilled the inclusion criteria (mean age 69.16±3.68 years, 56% men) were included. The control group was comprised of 14 patients, while the OSAS group consisted of 112 patients (31 mild, 44 moderate and 37 severe cases). No differences were observed in age, sex, hip circumference, waist/hip ratio or comorbidities between the groups. The Epworth Sleepiness Scale score, body mass index (BMI), and waist circumference were significantly higher in OSAS patients than in controls (p=0.001, p=0.02, and p=0.36, respectively). Uric acid was not correlated with any of the sleep parameters, and no significant differences were detected between the groups. Hyperuricemic patients were similar in terms of sleep parameters and comorbidities in comparison with the other patients.

CONCLUSIONS

No relationship was observed between uric acid level and OSAS severity, as defined by the apnoea-hypopnea index. Further studies are needed to determine the value of uric acid as a marker of OSAS, after controlling for cardiovascular comorbidities, in older patients with this syndrome.

Usefulness of Cathepsin S to Predict Risk for Obstructive Sleep Apnea among Patients with Type 2 Diabetes

Background

Obstructive sleep apnea (OSA) was highly prevalent in patients with type 2 diabetes (T2D). Cathepsin S (CTSS), a cysteine protease, is involved in the inflammatory activity in T2D and hypoxia conditions. The aim of the study was to evaluate whether CTSS could be involved in the inflammatory reaction of OSA in patients with T2D.

Methods

We included 158 participants in this study matched for age, gender, and body mass index in 4 groups (control, non-OSA&T2D, OSA&non-T2D, and OSA&T2D). After overnight polysomnography, we collected the clinical data including anthropometrical characteristics, blood pressure, and fasting blood samples in the morning. Plasma CTSS concentration was evaluated using the human Magnetic Luminex Assay.

Results

Compared with the control group, both the non-OSA&T2D group and the OSA&non-T2D group showed higher CTSS levels. Plasma CTSS expression was significantly increased in subjects with OSA&T2D compared to subjects with non-OSA&T2D. The OSA&T2D group had higher CTSS levels than the OSA&non-T2D group, but there were no statistically significant differences. Plasma CTSS levels showed significant correlation with the apnea-hypopnea index (AHI) (r = 0.559, P < 0.001) and plasma fasting blood glucose (r = 0.427, P < 0.001). After adjusting confounding factors, plasma CTSS levels were independently associated with the AHI (Beta: 0.386, 95% confidence intervals (CI): 21.988 to 57.781; P < 0.001). Furthermore, we confirmed the higher pinpoint accuracy of plasma CTSS in the diagnosis of OSA (area under the curve: 0.868).

Conclusions

Plasma CTSS expression was significantly elevated in the OSA&T2D group and was independently associated with the AHI; it could be a biomarker with a positive diagnostic value on diagnosing OSA among patients with T2D.

Impact of Uric Acid on Hypertension Occurrence and Target Organ Damage: Insights From the STANISLAS Cohort With a 20-Year Follow-up

BACKGROUND

Recent studies have shown that hyperuricemia may be associated with incident hypertension (HTN). We examined whether serum uric acid (SUA) is a predictor of HTN and target organ damage (TOD) 20 years later in initially healthy middle-aged individuals.

METHODS

Participants from the Suivi Temporaire Annuel Non-Invasif de la Santé des Lorrains Assurés Sociaux (STANISLAS) a single-center familial longitudinal cohort study (961 initially healthy adults and 570 children) underwent clinical and laboratory measurements at baseline and after approximately 20 years. Blood pressure (BP: using ambulatory BP measurements), urine albumin-to-creatinine ratio, estimated glomerular filtration rate (eGFR), left ventricular hypertrophy (LVH), diastolic dysfunction, and carotid-femoral pulse wave velocity (PWV) were measured at the end of follow-up.

RESULTS

In the parent population, higher baseline or last SUA levels and higher change in SUA (ΔUA) were significantly associated with an increased risk of HTN development, even after adjusting for known HTN risk factors (all P < 0.01). Higher baseline SUA was marginally associated with an increased risk of having high carotid-femoral PWV (P = 0.05). The association of SUA with BP increase was body mass index dependent (the increase in BP being greater in leaner subjects; interactionp < 0.05), and the association of SUA with eGFR decline was age dependent (the decline in eGFR being greater in older subjects; interactionp < 0.05). There was no significant association between SUA and diastolic dysfunction or LVH. In the whole population (i.e. including children), a significant association between SUA at baseline and the risk of HTN and higher carotid-femoral PWV was also found (both P < 0.02).

CONCLUSIONS

Increased SUA is associated with the development of HTN and vascular/renal TOD in initially healthy midlife subjects.

Confounded by obesity and modulated by urinary uric acid excretion, sleep-disordered breathing indirectly relates to hyperuricaemia in males: A structural equation model

Sleep-disordered breathing (SDB) causes hypoxic stress and can trigger uric acid (UA) overproduction. We comprehensively investigated whether SDB, interacting with components of metabolic syndrome, hepatic and renal dysfunctions, low physical fitness, sedentary lifestyle, disrupted sleep, and chronic systemic inflammation (CSI), is directly associated with hyperuricaemia. In 528 community-based males (mean [SD] age 46.2 [7.4] years), we cross-sectionally analysed measures of anthropometry; self-reported lifestyle habits; overnight sleep polysomnography data; cardiopulmonary exercise tests; and biomarkers of cardiometabolic, hepatic, and renal functions; and CSI, using structural equation modelling. Objective disrupted sleep, C-reactive protein, low physical fitness, and sedentary lifestyle were not related to UA levels in univariate analysis and were excluded. The latent variables (with corresponding manifest variables) obesity (body mass index, waist-hip ratio), hypertension (post-sleep systolic, diastolic blood pressure), dyslipidaemia (total cholesterol, triglyceride/high-density lipoprotein cholesterol), hepatic dysfunction (alanine aminotransferase, aspartate transaminase), and renal dysfunction (blood urea nitrogen, serum creatinine) were positively; and hyperglycaemia (fasting glucose, glycated haemoglobin) was negatively associated with hyperuricaemia (serum UA), except for SDB (Apnea-Hypopnea Index, percentage of oxygen saturation <90% period against total sleep time, oxygen desaturation index) in the one-stage influence model. In the two-stage model, SDB, closely interacting with obesity, was positively indirectly associated with hyperuricaemia through directly linked renal dysfunction and obesity-linked hypertension, inverse hyperglycaemia, dyslipidaemia, and hepatic dysfunction. In conclusion, structural equation modelling reveals that SDB closely interacts with obesity and is positively but indirectly related to hyperuricaemia in males. This suggests that urinary UA excretion modulates and obesity confounds the SDB-hyperuricaemia relationship.

Neck circumference is an independent risk factor for hyperuricemia within 3 years in women: a longitudinal study

INTRODUCTION

Our previous cross-sectional study revealed the association between neck circumference (NC) and hyperuricemia. This study aimed to further investigate the longitudinal association between NC and hyperuricemia and to compare the strengths of longitudinal association of NC and waist circumference (WC) with hyperuricemia.

METHODS

A total of 4383 subjects without hyperuricemia at baseline were included. Multivariable linear regression was used to assess the association between baseline anthropometric indices and uric acid level at follow-up. Cox regression was used to assess the relationship between baseline anthropometric indices and the risk of future hyperuricemia. A receiver-operating characteristic curve was used to compare the predictive ability of baseline anthropometric indices for future hyperuricemia.

RESULTS

Among women, only baseline NC was positively, linearly associated with uric acid level at follow-up (β = 1.75) and risk of future hyperuricemia (p_trend < 0.05); risk of hyperuricemia in the third and fourth quartile groups of baseline NC significantly increased, compared with the first quartile group of baseline NC (HR = 1.48 and 1.81, respectively). Among men, neither NC nor WC was associated with hyperuricemia after adjusting for confounder factors. The area under the curve of baseline NC and WC for hyperuricemia was comparable in both genders (0.606 for NC and 0.599 for WC in women, 0.578 for NC and 0.602 for WC in men).

CONCLUSIONS

For women, only baseline NC is an independent risk factor of hyperuricemia within 3 years. NC and WC have a similar 3-year predictive ability for hyperuricemia in both genders. Key Points • This is the first study to assess the longitudinal association between neck circumference and hyperuricemia. • According to the results of this study, we propose for the first time that neck circumference is an independent risk factor for hyperuricemia in women in the future, rather than waist circumference. • We found for the first time that neck circumference and waist circumference have similar predictive ability for future hyperuricemia in both genders.

Obstructive sleep apnea and the risk of gout: a population-based case-control study

Background

Patients with obstructive sleep apnea (OSA) might be at risk of gout because of pathophysiological mechanisms that can lead to hyperuricemia and eventually gout or because of shared risk factors between both diseases. The objective of the present study was to investigate the risk of gout in patients with OSA.

Methods

A population-based case-control study using the UK Clinical Practice Research Datalink GOLD including all patients aged 40 years and older with a first diagnosis of gout between 1987 and 2014. Gout cases were matched by year of birth, sex, and practice to non-gout controls. Conditional logistic regression estimated the risk of gout with an earlier diagnosis of OSA. Analyses were adjusted for lifestyle factors, comorbidities, and recent drug use.

Results

One hundred eleven thousand five hundred nine cases were matched with 210,241 controls. Patients with OSA were at increased risk of gout (OR 1.86; 95%CI (1.71–2.02). However, this association disappeared (OR 1.05; 95% CI 0.96–1.16) after adjustment for smoking status, body mass index (BMI), alcohol use, a history of heart failure, diabetes mellitus, renal function, and recent use of diuretics and other medications. Among females with OSA and patients with OSA associated with heart failure, renal impairment, or higher BMI, the risk of gout was however still increased when compared to the total control population.

Conclusion

This study showed that the observed association between OSA and gout disappeared after adjustment.

The Effect of Urine pH and Urinary Uric Acid Levels on the Development of Contrast Nephropathy

BACKGROUND

Hyperuricemia may cause acute kidney injury by activating inflammatory, pro-oxidative and vasoconstrictive pathways. In addition, radiocontrast causes an acute uricosuria, potentially leading to crystal formation. We therefore aimed to investigate the effect of urine acidity and urine uric acid level on the development of contrast-induced nephropathy (CIN) in patients undergoing elective coronary angiography.

METHODS

We enrolled 175 patients who underwent elective coronary angiography. CIN was defined as a >25% increase in the serum creatinine levels relative to basal values 48-72 h after contrast use. Prior to coronary angiography and 48-72 h later, serum uric acid, urea, creatinine, bicarbonate levels, and spot uric acid to creatinine ratio (UACR) were measured.

RESULTS

Of the 175 subjects included, 29 (16.6%) developed CIN. Those who developed CIN had a higher prevalence of diabetes, higher UACR (0.60 vs. 0.44, p = 0.014), higher contrast volume, and lower serum sodium level. With univariate analysis of a logistic regression model, the risk of CIN was found to be associated with diabetes (p = 0.0016, OR = 3.8 [95% CI: 1.7-8.7]), urine UACR (p = 0.0027, OR = 9.6 [95% CI: 2.2-42.2]), serum sodium (p = 0.0079, OR = 0.8 [95% CI: 0.77-0.96]), and contrast volume (p = 0.0385, OR = 1.8 [95% CI: 1.03-3.09]). In a multiple logistic regression model with stepwise method of selection, diabetes (p = 0.0120, OR = 3.2 [95% CI: 1.3-8.1]) and UACR (p = 0.0163, OR = 6.9 [95% CI: 1.4-33.4]) were the 2 risk factors finally identified.

CONCLUSIONS

We have demonstrated that higher urine UACR is associated with the development of CIN in patients undergoing elective coronary angiography.

Risk Factors For Hyperuricemia In Chinese Centenarians And Near-Centenarians

Purpose

Hyperuricemia is an important potential pathogenic factor for hypertension, cardiovascular disease and stroke. The current study aimed to investigate the prevalence of hyperuricemia and its relationship to lifestyle characteristics and dietary habits in centenarians and near-centenarians.

Patients and methods

In total, 966 centenarians and 788 near-centenarians were included. Community-based surveys were conducted to collect information about lifestyle. Blood examinations were performed using enzymatic assays. T-tests and χ2 tests were used to investigate significant indicators of hyperuricemia, and multivariate logistic regression was used to analyze the related risk factors. A comprehensive analysis of nineteen modifiable factors, including lifestyle characteristics, dietary habits, general characteristics and blood test indexes, was conducted.

Results

The prevalence of hyperuricemia was 29.02%. The percentage of men, waist circumference (WC), waist-hip ratio, estimated glomerular filtration rate (eGFR), levels of total protein (TP), alanine aminotransferase, aspartate aminotransferase, triglycerides, high-density lipoprotein cholesterol, serum homocysteine, serum uric acid, serum urea and serum creatinine, passive smoking, alcohol consumption, snoring, preference for fried flavors, and meat, seafood and vegetable consumption were significantly different between the hyperuricemia group and the normouricemia group (p<0.05). Multivariate logistic regression analysis showed that WC (OR=1.020), eGFR (OR=0.960), TP level (OR=1.038), serum urea level (OR=1.154), passive smoking (OR=2.589), snoring (OR=2.003), meat consumption (OR=2.506), seafood consumption (OR=1.422) and vegetable consumption (OR=0.521) were significantly associated with the risk of hyperuricemia (p<0.05).

Conclusion

Low eGFR and vegetable consumption, high WC, TP, and serum urea levels, passive smoking, snoring, and high meat and seafood consumption were independent risk factors for hyperuricemia. It is recommended that people at high risk for hyperuricemia should actively limit their intake of fried food, alcohol and purine-rich food, increase their intake of fresh vegetables, actively treat sleep apnea syndrome, avoid passive smoking, maintain a healthy WC and seek to improve their kidney and liver function.

Elevation in serum uric acid levels predicts favourable response to erlotinib treatment in patients with metastatic non-small-cell lung cancer

WHAT IS KNOWN AND OBJECTIVE

Erlotinib is a small molecule tyrosine kinase inhibitor which blocks the activation of epidermal growth factor receptor (EGFR), a transmembrane receptor that is upregulated in many cancer types. Inhibition of angiogenesis with consequent impairments in intratumoral microcirculation is one of the mechanisms through which EGFR inhibition halts the progression of cancer. A consequence of impaired microcirculation is intratumoral hypoxia, which results in increases in serum uric acid levels. The goal of this study was to investigate the relationship between serum uric acid levels and response to erlotinib in metastatic non-small-cell lung cancer (NSCLC).

METHODS

A total of 56 patients with metastatic non-small-cell lung cancer who received erlotinib for a duration of at least 3 months were included in this retrospective cohort study. Demographic characteristics, progression status, baseline serum uric levels and 3-month serum uric acid levels were recorded and analysed.

RESULTS AND DISCUSSION

Of the study population, 21 (37.5%) were female and 35 (62.5%) were male patients. No significant difference in above demographic characteristics was observed among exitus, survivor with progression and survivor without progression groups. Patients who responded favourably to erlotinib with no progression of their disease had significantly increased uric acid levels at 3-month follow-up (P = .01). Such a correlation was not observed if the patient was exitus (P = .47) or had progressed on erlotinib therapy (P = .19).

WHAT IS NEW AND CONCLUSION

In conclusion, this study is the first to demonstrate significant increases in serum uric acid levels in patients with metastatic NSCLC who responded favourably to erlotinib and had no progression under erlotinib therapy. Further studies are required to confirm and characterize serum uric acid as a novel biomarker in predicting the outcome in those with metastatic NSCLC.

Does Continuous Positive Airway Pressure Therapy in Patients with Obstructive Sleep Apnea Improves Uric Acid? A Meta-Analysis

Purpose

The efficacy of obstructive sleep apnea (OSA) therapy with continuous positive airway pressure (CPAP) on uric acid (UA) yielded conflicting results. This meta-analysis was performed to assess whether OSA treatment with CPAP could reduce UA levels.

Methods

The Web of Science, Cochrane Library, Embase, and PubMed were searched before March 2019. Information of patients, study design, and pre- and post-CPAP treatment of UA was utilized for analysis. The overall effects were analyzed via the standardized mean difference (SMD) with a 95% confidence interval (CI). Five studies were obtained and the meta-analysis was performed using Stata 12.0 and Review Manager 5.2.

Results

A total of 5 studies with 6 cohorts (2 RCT and 3 observational studies) involving 270 patients were pooled into meta-analysis. There was no change of UA levels before and after CPAP treatment in OSA patients (SMD = ‐0.20, 95% CI: -0.78 to 0.37, Z = 0.69, p = 0.49). Subgroup analysis showed that the outcomes were not affected by age of patients, gender distribution, baseline body mass index, daily duration, duration of CPAP treatment, sample size, and study design.

Conclusions

This meta-analysis revealed that CPAP treatment has no effect on UA in OSA patients. Further well-designed, large-scale randomized controlled trials are required to address this issue.

Serum Uric Acid Is Independently Associated with Risk of Obstructive Sleep Apnea-Hypopnea Syndrome in Chinese Patients with Type 2 Diabetes

Purpose

We aimed to investigate the association between serum uric acid (SUA) levels and obstructive sleep apnea-hypopnea syndrome (OSAHS) in patients with type 2 diabetes.

Methods

A cross-sectional study of 212 type 2 diabetes mellitus (T2DM) patients was conducted in Xiamen, China. All patients underwent polysomnography (PSG) recordings for OSAHS diagnosis. Patients were grouped according to the apnea-hypopnea index (AHI) as mild (5-14.9), moderate (15-29.9), and severe (≧30) OSAHS. Patients with AHI ≤ 4.9 served as the control group. Weight, body mass index (BMI), SUA, liver function, renal function, blood pressure, lipid profiles, and glycemic parameters were measured.

Results

A total of 158 patients (101 men and 57 women) with complete data were analyzed in this study. 127 patients were identified as OSAHS. Among the 127 patients with OSAHS, 56 (44.1%), 37 (29.1%), and 34 (26.8%) had mild, moderate, and severe OSAHS, respectively. Correlation analyses showed that the SUA level was significantly related to the apnea-hypopnea index (AHI) (r = 0.194, p = 0.016). The level of SUA was significantly higher among OSAHS patients compared to the control group (control group: 333.14 ± 80.52 μmol/L, mild group: 345.50 ± 90.27 μmol/L, moderate group: 363.59 ± 134.26 μmol/L, and severe group: 428.37 ± 123.58 μmol/L and p = 0.029). Multivariable logistic regression analyses showed that SUA was the independent risk factor for OSAHS (OR: 1.006, 95% CI: 1.001-1.011, p = 0.020).

Conclusions

The SUA level is significantly associated with the severity of OSAHS and should be controlled when managing OSAHS.

Continuous Positive Airway Pressure Treatment Does not Reduce Uric Acid Levels in OSA Women

OBJECTIVES

Although an association between uric acid (UA) levels and obstructive sleep apnea (OSA) has been reported, the effect of continuous positive airway pressure (CPAP) on this measure is yet unclear. We aimed to investigate the effect of CPAP therapy on serum UA levels in patients with OSA.

METHODS

We conducted a multicenter, open-label, randomized controlled trial in 307 women diagnosed with moderate-to-severe OSA (apnea-hypopnea index [AHI]≥15) in 19 Spanish Sleep Units. Women were randomized to CPAP (n=151) or conservative treatment (n=156) for 12 weeks. Changes in serum UA measures were assessed on an intention-to-treat basis. Additional analyses were conducted in the subgroup of women with CPAP adherence ≥4h/night and those with UA levels ≥6mg/dl.

RESULTS

Women had a mean (SD) age of 57.1 (10.1) years, median (first-third quartile) body mass index of 33.7 (29.0-38.5) mg/kg² and AHI of 32.0 (22.6-48.5). The average serum UA measure was 5.11 (1.26) mg/dl, and 80 (26.1%) participants had UA≥6mg/dl. Compared with the control group, the CPAP group did not achieve any reduction in UA levels (non-adjusted intergroup difference -0.03mg/dl, 95%CI -0.20 to 0.13; p=0.702) after 12 weeks of follow-up. These results did not change when the analysis was restricted to women with CPAP adherence ≥4h/night, or the subgroup of women with hyperuricemia.

CONCLUSIONS

Twelve weeks of CPAP therapy does not reduce UA levels compared to conservative treatment in women with moderate-to-severe OSA.

Evaluation of Inflammatory Markers in a Large Sample of Obstructive Sleep Apnea Patients without Comorbidities

Systemic inflammation is important in obstructive sleep apnea (OSA) pathophysiology and its comorbidity. We aimed to assess the levels of inflammatory biomarkers in a large sample of OSA patients and to investigate any correlation between these biomarkers with clinical and polysomnographic (PSG) parameters. This was a cross-sectional study in which 2983 patients who had undergone a polysomnography for OSA diagnosis were recruited. Patients with known comorbidities were excluded. Included patients (n = 1053) were grouped according to apnea-hypopnea index (AHI) as mild, moderate, and severe. Patients with AHI < 5 served as controls. Demographics, PSG data, and levels of high-sensitivity C-reactive protein (hs-CRP), fibrinogen, erythrocyte sedimentation rate (ESR), and uric acid (UA) were measured and compared between groups. A significant difference was found between groups in hs-CRP, fibrinogen, and UA. All biomarkers were independently associated with OSA severity and gender (p < 0.05). Females had increased levels of hs-CRP, fibrinogen, and ESR (p < 0.001) compared to men. In contrast, UA levels were higher in men (p < 0.001). Our results suggest that inflammatory markers significantly increase in patients with OSA without known comorbidities and correlate with OSA severity. These findings may have important implications regarding OSA diagnosis, monitoring, treatment, and prognosis. This trial is registered with ClinicalTrials.gov number NCT03070769.

The management of gout in different clinical specialties in Turkey: a patient-based survey

Although gout is potentially curable, the management of this disease is often suboptimal. In this study, we investigated the treatment of gout in Turkey and also compared the management approaches to gout in different clinical specialties. Three hundred and nineteen consecutive patients (mean age 58.60 ± 12.8 years; 44 females, 275 males) were included in this multicenter study. A standardized form was generated to collect data about the patient's first admission to health care, the specialty of the doctor first diagnosed the gout, the treatment options for gout including attack management, patient referral, chronic treatment including medical treatment, and life style modifications. Forty patients were referred to another center without any treatment (12.8 %), and referral rate is most common among the primary care physicians (28.8 %). Colchicine was more commonly used for attack prophylaxis than allopurinol. Ninety-two patients had never been treated with allopurinol (28.8 %). Allopurinol prescription was less common among the primary care physicians and orthopedists, and highest among the rheumatologists. Recommendation of diet and life style modifications was less common among the primary care physicians and orthopedists, and highest among the rheumatologists. The rates of life style modification recommendation and long-term allopurinol prescription were 83.7 and 77.6 %, respectively, among the rheumatologists. Both acute and chronic management of gout is suboptimal in Turkey especially among the primary care physicians and orthopedists. Moreover, chronic treatment is even suboptimal among rheumatologists.

Uric Acid is a Useful Tool to Predict Contrast-Induced Nephropathy

Developing contrast-induced nephropathy (CIN) after primary percutaneous coronary intervention (pPCI) has a negative impact on survival and morbidity. We assessed the predictive value of serum uric acid (SUA) for the development of CIN in patients with ST-segment elevation myocardial infarction (STEMI) who underwent pPCI. Contrast-induced nephropathy was defined an increase of ≥25% or ≥0.5 mg/dL in creatinine concentrations within 72 hours after pPCI. Patients were divided into 2 groups according to admission median SUA level. Serum uric acid level was <5.4 mg/dL (group 1; n = 222) and ≥5.4 mg/dL (group 2; n = 228). Compared to group 1, development of CIN (12% vs 20%, P < .001) was significantly greater in group 2. Using a cut point of >5.45 mg/dL, the SUA level predicted development of CIN with a sensitivity of 70% and specificity of 67%. In multiple logistic regression analysis, SUA level, diabetes mellitus, left ventricular ejection fraction <50%, contrast volume, estimated glomerular filtration rate, and C-reactive protein level emerged as independent predictors of CIN. In conclusion, elevated SUA is an independent risk factor for the development of CIN after pPCI in patients with STEMI.

Potential causal associations between vitamin D and uric acid: Bidirectional mediation analysis

Vitamin D deficiency, a major public-health worldwide, is associated with hyperuricemia but casual association is questioned. The study was conducted to determine potential causal associations between 25-hydroxy vitamin D (25(OH)D) and uric acid (UA). A cross-sectional study of the Electricity Generating Authority of Thailand (EGAT3) cohort was conducted. Subjects (n = 2,288) were used to genotype the group-specific component (GC) at rs2282679 and ATP-binding cassette subfamily G member 2 (ABCG2) at rs2231142. Mediation analysis with 1000-replication bootstrap was applied to construct causal pathways i.e., rs2282679 → 25(OH)D → UA and rs2231142 → UA → 25(OH)D: The mediator (i.e., 25(OH)D and UA) was firstly regressed on the studied gene (i.e., rs2282679 and rs2231142). A potential causal effect of C allele on UA through 25(OH)D was -0.0236 (95% CI: -0.0411, -0.0058), indicating every minor C allele resulted in decreasing the 25(OH)D and then significantly decreased the UA by 0.0236 unit. For the second pathway, the mediation effect was 0.0806 (95% CI: 0.0107, 0.1628); every T allele copy for rs2231142 increased UA and thus increased 25(OH)D by 0.0806 unit. Our study suggested potential causal associations between the GC gene and UA through the 25(OH)D mediator, and the ABCG2 and the 25(OH)D through the UA mediator but the absolute effects are very clinically small.