Sex-specific Relationship of Serum Uric Acid with All-cause Mortality in Adults with Normal Kidney Function: An Observational Study

The association between serum uric acid / serum creatinine ratio and in-hospital outcomes in elderly patients with acute myocardial infarction

BACKGROUND

The role of Serum uric acid (SUA) in acute myocardial infarction (AMI) was controversial, which might be influenced by the renal clearance function of the patients. The present study aimed to explore the association between serum uric acid to serum creatinine ratio (SUA/Scr), reflecting a net production of SUA, and the in-hospital outcomes of elderly patients with AMI.

METHODS

In this retrospective study, a total of 330 elderly AMI patients (≥ 75 years) were enrolled. Data of SUA and Scr on admission were collected to calculate SUA/Scr ratio. Logistic regression analysis and receiver-operating curves were performed to assess the association between SUA/Scr ratio and in-hospital major adverse cardiovascular events (MACEs) and all-cause death.

RESULTS

Among the 330 patients, 68 patients had MACEs and 44 patients died. Patients with MACEs or died had lower SUA/Scr values compared with those without MACEs or survival (P < 0.05). Univariate logistic analysis showed that a lower value of SUA/Scr (< 3.45) was significantly associated with in-hospital MACEs (odd ratios (OR): 2.359, 95% confidential interval (CI): 1.369-4.065, P = 0.002) and death (OR: 2.424, 95% CI: 1.275-4.608, P = 0.007). After correcting for confounding factors, a lower SUA/Scr value was still independently associated with in-hospital MACEs (OR: 2.144, 95% CI: 1.169-3.934, P = 0.014) and death (OR: 2.125, 95% CI: 1.050-4.302, P = 0.036). Subgroup analysis showed that the association between a lower SUA/Scr ratio and increased risk of in-hospital outcomes could observed only in males (OR: 2.511, 95%CI: 1.211-5.207, P = 0.013 for MACEs; OR: 2.730, 95% CI: 1.146-6.502, P = 0.023 for death).

CONCLUSIONS

A lower SUA/Scr ratio was associated with an increased risk of in-hospital adverse events in elderly patients with AMI, especially in males, which maybe a marker of poor outcomes for elderly AMI patients.

Sex differences between serum uric acid levels and cardiovascular outcomes in patients with coronary artery disease after stent implantation

Background

The relationship between elevated serum uric acid (SUA) levels and cardiovascular outcomes after stent implantation remains uncertain. This study sought to evaluate the impact of SUA on 12-month cardiovascular outcomes after stent implantation.

Methods

We performed a retrospective study of patients who successfully underwent stent implantation and enrolled 3,222 patients with coronary artery disease (CAD) from a single center. SUA levels were measured before stent implantation. The patients were divided into six groups (<4, 4-4.9, 5-5.9, 6-6.9, 7-7.9 and ≥ 8 mg/dL) at SUA intervals of 1.0 mg/dL. The incidence of cardiovascular outcomes in the six groups was monitored for 1 year after stent implantation and the hazard ratios were estimated. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for cardiovascular outcomes were estimated using a Cox proportional hazard regression analysis. The primary endpoint was all-cause death. The secondary endpoint was a composite of all-cause death, myocardial infarction, target vessel revascularization, stent thrombosis and stroke. The follow-up duration was 12 months.

Results

Over the 12-month follow-up period, there were 101 all-cause deaths and 218 MACCE. After adjustment for several parameters, the group with SUA levels of more than or equal to 8 mg/dL had significantly higher hazard ratios in the incidence of all-cause death or MACCE. The group with <4.0 mg/dL had significantly higher hazard ratios in all-cause death only in male patients. In contrast, there were no significant differences observed for cardiovascular outcomes in female patients.

Conclusions

Our study identified a U-shaped association between SUA levels and cardiovascular outcomes during 12-month follow-up for males, but not for females. Further studies are warranted to clarify the sex differences between SUA levels and clinical outcomes.

Association of serum uric acid with all-cause and cardiovascular mortality among adults with nonalcoholic fatty liver disease

AIM

The association between serum uric acid (SUA) and mortality from cardiovascular diseases (CVDs) in nonalcoholic fatty liver disease (NAFLD) participants remains uncertain. We aim to investigate the relations of SUA with the risk of CVD mortality among adults with and without NAFLD.

METHODS

Using data from National Health and Nutrition Examination Survey (NHANES) 1999-2014, a total of 17,858 participants were recruited. Of these, 5767 had a US Fatty Liver Index (USFLI) ≥30 and were classified as having NAFLD. Death information was obtained from the National Death Index until 2015.

RESULTS

During a mean follow-up of 8.3 years, 427 participants died from CVD. Overall, there was a positive association between SUA and CVD mortality among participants with NAFLD (per SD μmol/L increment, adjusted hazard ratio [HR], 1.40; 95% confidence interval [CI], 1.16-1.68). Accordingly, among those with NAFLD, when SUA was assessed as quartiles, compared with those in the first quartile, a significantly higher risk of CVD mortality was found in participants in the fourth quartile (adjusted HR, 2.69; 95% CI, 1.51-4.80). However, there was no significant association between SUA and CVD mortality among participants without NAFLD (per SD μmol/L increment, adjusted HR, 1.01; 95% CI, 0.83-1.22). Similar trends were found for all-cause mortality. Similar results were also found when using FLI ≥ 60 to define NAFLD.

CONCLUSIONS

In a large and nationally representative sample of US adults, a higher SUA was significantly associated with a higher risk of CVD mortality among participants with NAFLD, but not in those without NAFLD.

Engineered Escherichia coli Nissle 1917 with urate oxidase and an oxygen-recycling system for hyperuricemia treatment

Hyperuricemia is the second most prevalent metabolic disease to human health after diabetes. Only a few clinical drugs are available, and most of them have serious side effects. The human body does not have urate oxidase, and uric acid is secreted via the kidney or the intestine. Reduction through kidney secretion is often the cause of hyperuricemia. We hypothesized that the intestine secretion could be enhanced when a recombinant urate-degrading bacterium was introduced into the gut. We engineered an Escherichia coli Nissle 1917 strain with a plasmid containing a gene cassette that encoded two proteins PucL and PucM for urate metabolism from Bacillus subtilis, the urate importer YgfU and catalase KatG from E. coli, and the bacterial hemoglobin Vhb from Vitreoscilla sp. The recombinant E. coli strain effectively degraded uric acid under hypoxic conditions. A new method to induce hyperuricemia in mice was developed by intravenously injecting uric acid. The engineered Escherichia coli strain significantly lowered the serum uric acid when introduced into the gut or directly injected into the blood vessel. The results support the use of urate-degrading bacteria in the gut to treat hyperuricemia. Direct injecting bacteria into blood vessels to treat metabolic diseases is proof of concept, and it has been tried to treat solid tumors.

Hypouricemia and Urate Transporters

Hypouricemia is recognized as a rare disorder, defined as a serum uric acid level of 2.0 mg/dL or less. Hypouricemia is divided into an overexcretion type and an underproduction type. The former typical disease is xanthinuria, and the latter is renal hypouricemia (RHUC). The frequency of nephrogenic hypouricemia due to a deficiency of URAT1 is high in Japan, accounting for most asymptomatic and persistent cases of hypouricemia. RHUC results in a high risk of exercise-induced acute kidney injury and urolithiasis. It is vital to promote research on RHUC, as this will lead not only to the elucidation of its pathophysiology but also to the development of new treatments for gout and hyperuricemia.

U-shaped association of uric acid to overall-cause mortality and its impact on clinical management of hyperuricemia

Serum uric acid (SUA) is significantly elevated in obesity, gout, type 2 diabetes mellitus, and the metabolic syndrome and appears to contribute to the renal, cardiovascular and pulmonary comorbidities that are associated with these disorders. Most previous studies have focused on the pathophysiologic effects of high levels of uric acid (hyperuricemia). More recently, research has also shifted to the impact of hypouricemia, with multiple studies showing the potentially damaging effects that can be caused by abnormally low levels of SUA. Along with these observations, recent inconclusive data from human studies evaluating the treatment of hyperuricemia with xanthine oxidoreductase (XOR) inhibitors have added to the debate about the causal role of UA in human disease processes. SUA, which is largely derived from hepatic degradation of purines, appears to exert both systemic pro-inflammatory effects that contribute to disease and protective antioxidant properties. XOR, which catalyzes the terminal two steps of purine degradation, is the major source of both reactive oxygen species (O2^.-, H₂O₂) and UA. This review will summarize the evidence that both elevated and low SUA may be risk factors for renal, cardiovascular and pulmonary comorbidities. It will also discuss the mechanisms through which modulation of either XOR activity or SUA may contribute to vascular redox hemostasis. We will address future research studies to better account for the differential effects of high versus low SUA in the hope that this will identify new evidence-based approaches for the management of hyperuricemia.

Serum uric acid level and all-cause and cardiovascular mortality in Chinese elderly: A community-based cohort study in Shanghai

BACKGROUND AND AIMS

The association between serum uric acid (SUA) and the all-cause and cardiovascular diseases (CVD) mortality remains controversial, but few studies based on the community population in Shanghai have been reported. We aimed to evaluate the association of SUA level with all-cause and CVD mortality in Chinese elderly based on a community-based cohort study in Shanghai of China.

METHODS AND RESULTS

A total of 12,071 eligible participants were included, with a cumulative follow-up period of 46,063.65 person-years and a median of 4.67 years. The time-dependent Cox regression model indicated that when SUA level was classified into quartile groups, no significant association was observed between SUA level and all-cause death in both men and women and between SUA level and CVD mortality in men. However, the HR (95%CI) between SUA groups and CVD death in women was 3.75 (1.49-9.43) for quartile 1, 3.66 (1.53-8.76) for quartile 2, and 2.98 (1.33-6.69) for quartile 4, respectively, when compared with the quartile 3 SUA level. A significant non-linear association was observed between SUA level and CVD death in elderly women. An increased risk of CVD death was observed among women with SUA level less than 4.30 mg/dL at the baseline, and a lower risk, among women with SUA level of 4.30-4.72 mg/dL at the baseline.

CONCLUSION

The non-linear association between SUA level and CVD mortality in elderly women suggests a potential benefit of controlling SUA level at4.30-4.72 mg/dL in elderly Chinese women.

Role of asymptomatic hyperuricemia in the progression of chronic kidney disease and cardiovascular disease

Previous research has investigated whether hyperuricemia serves as an independent risk factor for cardiovascular and renal diseases. Hyperuricemia is defined as an abnormally high level of uric acid (UA; i.e., serum urate level > 6.8 mg/dL). Hyperuricemia has been considered a complication of chronic kidney disease (CKD). However, it seems to play a pathogenic role in the progression of renal diseases. There has been increasing focus on the link between hyperuricemia and CKD. The results of randomized controlled trials have implied independent associations between hyperuricemia and the progression of cardiovascular and renal morbidities. These associations may be mediated by renin-angiotensin system activation, nitric oxide synthase inhibition, and macrovascular/microvascular disease development. There remains controversy regarding the use of serum UA level as an indirect index of renal vascular disease. This literature review focuses on the role of asymptomatic hyperuricemia in the progression of CKD, as well as the association between hyperuricemia and cardiovascular disease. It also provides a general overview of the physiological metabolism of UA.

Metabolic risks in living kidney donors in South Korea

Background

Considering the growing prevalence of Western lifestyles and related chronic diseases occurring in South Korea, this study aimed to explore the progression of metabolic risk factors in living kidney donors.

Methods

This study enrolled living kidney donors from seven hospitals from 1982 to 2016. The controls were individuals that voluntarily received health check-ups from 1995 to 2016 that were matched with donors according to age, sex, diabetes status, baseline estimated glomerular filtration rate, and date of the medical record. Data on hyperuricemia, hypertension, hypercholesterolemia, and overweight/obesity were collected to determine metabolic risks. Logistic regressions with interaction terms between the medical record date and donor status were used to compare the trends in metabolic risks over time in the two groups.

Results

A total of 2,018 living kidney donors and matched non-donors were included. The median age was 44.0 years and 54.0% were women. The living kidney donors showed a lower absolute prevalence for all metabolic risk factors, except for those that were overweight/obese, than the non-donors. The proportion of subjects that were overweight/obese was consistently higher over time in the donor group. The changes over time in the prevalence of each metabolic risk were not significantly different between groups, except for a lower prevalence of metabolic risk factors ≥ 3 in donors.

Conclusion

Over time, metabolic risks in living kidney donors are generally the same as in non-donors, except for a lower prevalence of metabolic risk factors ≥3 in donors.

Cumulative Serum Uric Acid and Its Time Course Are Associated With Risk of Myocardial Infarction and All-Cause Mortality

Background Serum uric acid (SUA) has been demonstrated as a risk factor for myocardial infarction (MI) and all-cause mortality; however, the impact of cumulative SUA (cumSUA) remains unclear. We aimed to investigate the association of cumSUA with MI risk and all-cause mortality, and to further explore the effects of SUA accumulation time course. Methods and Results The study enrolled 53 463 participants without a history of MI, and these participants underwent 3 examinations during 2006 to 2010. cumSUA from baseline to the third examination was calculated, multiplying mean values between consecutive examinations by time intervals between visits. Cox models estimated hazard ratios (HRs) and 95% CIs of MI and all-cause mortality for cumSUA quartiles, hyperuricemia exposure duration, and SUA accumulation time course. During a median follow-up of 7.04 years, 476 incident MIs and 2692 deaths occurred. In the fully adjusted model, a higher MI risk was observed in the highest cumSUA quartile (HR, 1.48; 95% CI, 1.10-1.99), in participants with longer hyperuricemia exposure duration (HR, 1.71; 95% CI, 1.06-2.73), and in participants with cumSUA≥median and a negative slope (HR, 1.58; 95% CI, 1.18-2.11). Similar associations persisted for all-cause mortality. Conclusions The risk of MI and all-cause mortality increased with higher cumSUA and was affected by the SUA accumulation time course. Early SUA accumulation contributed more to MI risk and all-cause mortality than later SUA accumulation with the same overall cumulative exposure, emphasizing the importance of optimal SUA control early in life.

Uric acid is associated with cardiac death in patients with hypertrophic obstructive cardiomyopathy

BACKGROUND

The role of uric acid (UA) in survival of patients with hypertrophic obstructive cardiomyopathy (HOCM) has not been fully evaluated. This study aimed to determine whether UA could be an independent risk factor of cardiac death in patients with HOCM.

METHODS

A total of 317 patients with HOCM, who were receiving conservative treatment in Fuwai Hospital from October 2009 to December 2014, all of them completed UA evaluations, were analyzed. Patients were divided into three groups according to the UA levels: Tertile 1 (≤ 318 μmol/L, n = 106), Tertile 2 (319 to 397 μmol/L, n = 105), and Tertile 3 (≥ 398 μmol/L, n = 106).

RESULTS

During a median follow-up of 45 months, 29 cardiac deaths (9.1%) occurred, including 6 sudden cardiac deaths and 23 heart failure-related deaths. Cardiac death in Tertile 3 (n = 16, 55.2%) was significantly higher than in Tertile 1 (n = 6, 20.7%) and Tertile 2 (n = 7, 24.1%). In univariate model, UA level (continuous value) showed predictive value of cardiac death [hazard ratio (HR) = 1.006, 95% CI: 1.003−1.009,P = 0.009]. Univariate Cox survival analysis had shown a significant higher property of cardiac death in patients of Tertile 3 when compared with those of Tertile 1, but cardiac death in patients of Tertile 2 did not show significant prognositic value compared with those of Tertile 1 (HR = 3.927, 95% CI: 0.666−23.162,P = 0.131). UA was found to be an independent risk factor (HR = 1.005, 95% CI: 1.001−1.009,P = 0.009) of cardiac death in the multivariate regression analysis after the adjustment for age, body mass index, atrial fibrillation, hemoglobin, creatinine, high-sensitivity C-reactive protein, interventricular septum/left ventricular posterior wall ratio, left ventricular outflow tract and left ventricular ejection fraction.

CONCLUSIONS

UA concentration was found to be independently associated with cardiac death in HOCM patients receiving conservative treatment. Randomized trials of UA-lowering agents for HOCM patients are warranted.

Serum uric acid and mortality thresholds among men and women in the Irish health system: A cohort study

BACKGROUND

Elevation of serum uric acid (SUA) is associated with increased mortality; however, controversy exists regarding the nature of the relationship and differences between men and women. We explored relationships of SUA levels with all-cause mortality in a large cohort of patients within the Irish health system.

METHODS

A retrospective cohort study of 26,525 participants was conducted using data from the National Kidney Disease Surveillance System. SUA was modelled in increments of 59.48 µmol/L (1 mg/dL), Cox's proportional hazards model estimated hazard ratios (HRs) and 95% Confidence Intervals (CI), median lifetimes were also computed separately for men and women. Mortality patterns were further explored using penalised splines.

RESULTS

There were 1,288 (4.9%) deaths over a median follow-up of 5.1 years. In men, the risk of mortality was greatest for the lowest (<238 µmol/L) and highest (>535 µmol/L) categories [HR 2.35 (1.65-3.14) and HR 2.52 (1.87-3.29) respectively]; the corresponding median lifetimes for men were reduced by 9.5 and 11.7 years respectively compared to the referent. In women, mortality risks were elevated for SUA >416 mol/L [HR 1.69 (1.13-2.47) and beyond; the corresponding median lifetime for women were reduced by 5.9 years compared to the referent. Spline analysis revealed a U-shaped association between SUA and mortality in men, while for women, the pattern of association was J-shaped.

CONCLUSION

Mortality patterns attributed to SUA differ between men and women. Optimal survival was associated with SUA concentrations of 304-454 µmol/L for men and < 409 µmol/L for women.

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).

Prognostic Value of Serum Uric Acid in Hospitalized Heart Failure Patients With Preserved Ejection Fraction (from the Japanese Nationwide Multicenter Registry)

Elevated serum uric acid (UA) is associated with an increased risk of cardiovascular disease and worse clinical outcome in patients with cardiovascular disease. Nevertheless, the prognostic value of serum UA level in hospitalized heart failure patients with preserved ejection fraction (HFpEF) has not been fully elucidated. The aim of this study was to investigate whether serum UA level on admission could be associated with subsequent mortality in hospitalized patients with HFpEF. We examined 516 consecutive hospitalized HFpEF (left ventricular ejection fraction ≥50%) patients with decompensated heart failure from our HFpEF-specific multicenter registry who had serum UA data on admission. The primary outcome of interest was all-cause death. During a median follow-up period of 749 (interquartile range 540 to 831) days, 90 (17%) patients died. Higher serum UA level was significantly related to increased incidence of all-cause death (p = 0.016). In addition, patients with higher serum UA (≥6.6 mg/dl, median) and plasma B-type natriuretic peptide (≥401.2 pg/ml, median) levels had the highest incidence of all-cause death in the groups (p = 0.002). In multivariable Cox regression analysis, serum UA was an independent determinant of mortality (hazards ratio 1.23, 95% confidence interval 1.10 to 1.39) even after adjustment for prespecified confounders, renal function and the use of diuretics before admission. In conclusions, higher admission serum UA was an independent determinant of mortality in hospitalized HFpEF patients. Our findings indicate the importance of assessing admission serum UA level for further risk stratification in hospitalized patients with HFpEF.

U-shaped association between serum uric acid concentration and mortality in hypertrophic cardiomyopathy patients

Background. No study has examined the effect of low serum uric acid (SUA) concentrations on mortality in hypertrophic cardiomyopathy (HCM) patients. The aim of the present study was to assess the relations between both low and high SUA concentrations and the risk of mortality across the full range of SUA concentrations in a retrospective cohort of HCM patients.Methods. A total of 454 HCM patients were enrolled in the study, and SUA concentrations were measured at baseline. The primary and secondary endpoints were all-cause mortality and HCM-related mortality, respectively. The associations between SUA concentrations and endpoints were analysed.Results. During a median follow-up of 3.8 years, there were 80 (17.6%) all-cause mortality events, and 52 of them (11.5%) were ascribed to HCM-related mortality. Patients with SUA concentrations of 250-350 µmol/L had the lowest all-cause mortality rate (11.8%) and HCM-related mortality rate (5.0%). Both low and high SUA concentrations were associated with increased all-cause and HCM-related mortality. Adjusted HRs were 2.52 (95% CI 1.13-5.61, p = 0.024) and 4.86 (95% CI 1.74-13.58, p = 0.003) for all-cause mortality and HCM-related mortality in the lowest SUA group (<250 µmol/L) when compared with the reference group (250-350 µmol/L), respectively. The corresponding HRs in the highest SUA group (≥450 µmol/L) were 2.73 (95% CI 1.42-5.23, p = 0.003) and 4.14 (95% CI 1.70-10.13, p = 0.002), respectively.Conclusions. Both low and high SUA concentrations were significantly associated with increased risk of all-cause mortality and HCM-related mortality, which supported a U-shaped association between SUA concentrations and mortality in HCM patients.

Long-term Mortality Risks Among Living Kidney Donors in Korea

RATIONALE & OBJECTIVE

Living kidney donors may have a higher risk for death and kidney failure. This study aimed to investigate the long-term mortality experience of living kidney donors compared with members of the general public in Korea who underwent voluntary health examinations.

STUDY DESIGN

Cohort study.

SETTING & PARTICIPANTS

We first calculated standardized mortality ratios for 1,292 Korean living kidney donors who underwent donor nephrectomy between 1982 and 2016 and 72,286 individuals who underwent voluntary health examinations between 1995 and 2016. Next we compared survival between the 1,292 living kidney donors and a subgroup of the health examination population (n=33,805) who had no evident contraindications to living kidney donation at the time of their examinations. Last, a matched comparator group was created from the health examination population without apparent contraindication to donation by matching 4,387 of them to donors (n=1,237) on age, sex, body mass index, estimated glomerular filtration rate, urine dipstick albumin excretion, previously diagnosed hypertension and diabetes, and era.

EXPOSURES

Donor nephrectomy.

OUTCOMES

All-cause mortality and other clinical outcomes after kidney donation.

ANALYTICAL APPROACH

First, standardized mortality ratios were calculated separately for living kidney donors and the health examination population standardized to the general population. Second, we used Cox regression analysis to compare mortality between living kidney donors versus the subgroup of the health examination population without evident donation contraindications. Third, we used Cox regression analysis to compare mortality between living kidney donors and matched comparators from the health examination population without apparent contraindication to donation.

RESULTS

The living kidney donors and health examination population had excellent survival rates compared with the general population. 52 (4.0%) of 1,292 kidney donors died during a mean follow-up of 12.3±8.1 years and 1,072 (3.2%) of 33,805 in the health examiner subgroup without donation contraindications died during a mean follow-up of 11.4±6.1 years. Donor nephrectomy did not elevate the hazard for mortality after multivariable adjustment in kidney donors and the 33,805 comparators (adjusted HR, 1.01; 95% CI, 0.71-1.44; P=0.9). Moreover, living donors showed a similar mortality rate compared with the group of matched healthy comparators.

LIMITATIONS

Donors from a single transplantation center. Residual confounding owing to the observational study design.

CONCLUSIONS

Kidney donors experienced long-term rates of death comparable to nondonor comparators with similar health status.

Comparing Cardiovascular Safety of Febuxostat and Allopurinol in the Real World: A Population-Based Cohort Study

OBJECTIVE

To determine and compare the risk of cardiovascular events and mortality of febuxostat and allopurinol use.

PATIENTS AND METHODS

We conducted a cohort study using the Taiwan National Health Insurance Research Database. New users of febuxostat and allopurinol between April 1, 2012 and December 31, 2015 were identified, and the two groups were 1:1 matched by propensity score, benzbromarone use history, renal impairment, and time of drug initiation. The risk of major adverse cardiovascular events (MACEs), venous thromboembolism (VTE), heart failure (HF) hospitalization, atrial fibrillation hospitalization, cardiovascular (CV) death, and all-cause mortality was assessed using Cox proportional hazards models. The dose-response relationship between xanthine oxidase inhibitor use and adverse CV outcomes were also determined.

RESULTS

A total of 44,111 patients were included for each group, and all baseline covariates were well matched. Febuxostat users were at a significantly higher risk for HF hospitalization (hazard ratio [HR], 1.22; 95% CI, 1.13-1.33), atrial fibrillation hospitalization (HR, 1.19; 95% CI, 1.05-1.36), and CV death (HR, 1.19; 95% CI, 1.03-1.36) than allopurinol users, whereas no difference was found for the major adverse cardiac events composite endpoint, venous thromboembolism, myocardial infarction, ischemic stroke, and all-cause mortality. The elevated risk of HF hospitalization was consistent throughout the primary and sensitivity analyses. In addition, febuxostat increased the risk of adverse CV outcomes in a dose-dependent manner.

CONCLUSION

The use of febuxostat, compared with allopurinol, was associated with a significantly increased risk of adverse CV events. Higher febuxostat doses had a greater impact. Further studies are needed to investigate the mechanisms linking febuxostat to adverse CV outcomes.

Reference interval and upper decission limit for serum uric acid – an evidence-based approach on Romanian population using an a posteriori method

Introduction. There is accumulating evidence that high normal serum uric acid (SUA) levels of 6-7 mg/dL are associated with cardiovascular morbidity and metabolic syndrome (MetS), hence the need to redefine its upper limit of normal (ULN). We aimed to derive ULN based on statistics and evidence in a representative sample of the population and to observe its relation to MetS components.

Methods. All SUA measurements form a university rheumatology hospital were extracted between January 5th 2010 and March 21st 2018. SUA levels were measured by a single biochemist a unique type of commercially available kit. Follow-up measurements, patients with diagnoses influencing SUA levels and outlying measurements were excluded. ULNs were studied using least square analysis.

Results. Of the 22503 SUA measurements in the database, only 3318 came from normal individuals: 33.3% men (n=1105), 66.7% women (n = 2213). Least square analysis revealed the following SUA reference intervals (RI): 3.43-6.19 mg/dL for the combined sample; 4.44-7.01 mg/dL for men, 3.28-5.56 mg/dL for women. The values corresponding to the 66th percentile of each group presented lower ULNs: 5.36 mg/dL for all, 6.10 mg/dL for men, 4.90 mg/dL for women. The prevalence of hyperuricemia increased from 13.8% (manufacturer’s gender-specific ULN) to 19.9% (derived ULN). Mean SUA levels significantly increased with the number of MetS components.

Conclusion. We recommend that hyperuricemia should be defined using a statistical approach of ULN selection corresponding to the genderand population-specific 66th percentile of data range.

Associations between urate-lowering therapy and the risk of type 2 diabetes mellitus

Background

Gout is independently associated with increased risk of type 2 diabetes mellitus (T2DM). Urate-lowering therapy (ULT) might be beneficial in lowering the risks of T2DM. Therefore, we conducted a nested case-control study to evaluate the associations between ULT and T2DM.

Methods

This study retrieved the data of 29,765 gout patients from the period of 1998–2010 by using data from Taiwan’s National Health Insurance Research Database. Controls (n = 59,530) were matched at a 1:2 ratio by age, sex, and region. Multivariate Cox proportional hazards regression were performed to examine the dose-dependent relationship between ULT and T2DM.

Results

The adjusted Hazard ratio (HR) for the association of T2DM with allopurinol or benzbromarone exposure was 1.17 (95% confidence interval (CI) 1.07–1.28) and1.09 (95% CI 1.03–1.15), respectively. The HR for the cumulative allopurinol dose was 0.87 (95% CI 0.71–1.07) for patients with dose ≤1.3 mg/day and was 1.31 (95% CI 1.13–1.52) for those with a dose >15.2 mg/day. Similarly, the HR for the cumulative benzbromarone dose was 0.85(95% CI 0.75–0.96) for patients with a dose ≤1.3 mg/day and 1.42 (95% CI 1.30–1.55) for patients with a dose>9.4 mg/day, respectively. Moreover, the average exposure dose of >100 mg/day for allopurinol and >100 mg/day for benzbromarone was associated with a 1.28-fold (95% CI 1.11–1.48) and 1.47-fold (95% CI 1.23–1.76) T2DM risk respectively. The HR for patients in aged >50 years group with cumulative dose ≤1.3 mg/day of allopurinol or benzbromarone had lower risk of T2DM (HR = 0.74, 95% CI 0.58–0.94 for allopurinol; HR = 0.79, 95% CI 0.69–0.90 for benzbromarone).

Conclusion

Gout patients with prolonged ULT and a high dose of ULT were associated with a significant increase in T2DM risk. Although gout patients with age greater than 50 years and a lower dose of ULT may be beneficial in lowering T2DM risk, further clinical studies need to be confirmed these associations.

Gout lessons from 2018: CARES, a direct comparison of febuxostat vs allopurinol, and CANTOS, IL1 blocker for cardiovascular risk minimisation

In the Cardiovascular Safety of Febuxostat and Allopurinol in Patients with Gout and Cardiovascular Morbidities (CARES) trial conducted by White et al. (March 29 issue from NEJM), all-cause mortality and cardiovascular mortality are found to be higher among patients randomly assigned to febuxostat compared to allopurinol, but significant flaws are a clear lack of treat to target strategy with more powered treatment in the febuxostat arm, dysbalance with cardiovascular risk factors selectively in again the febuxostat arm, and discontinuation of the trial regimen in over 50% of patients with discontinuation of follow-up in about 45%. With these flaws, conclusions such as febuxostat-associated higher mortality are potentially if not probably incorrect, and thus febuxostat to be used not as first-line therapy may well be an invalid consequence? The paper here describes potential lessons to be taken.

U-Shaped Association Between Serum Uric Acid Level and Risk of Mortality: A Cohort Study

OBJECTIVE

In addition to the controversy regarding the association of hyperuricemia with cardiovascular disease (CVD) mortality, few studies have examined the impact of a low uric acid level on mortality. We undertook the present study to evaluate the relationship between both low and high uric acid levels and the risk of all-cause and cause-specific mortality in a large sample of Korean adults over a full range of uric acid levels.

METHODS

A cohort study was performed in 375,163 South Korean men and women who underwent health check-ups from 2002 to 2012. Vital status and cause of death were ascertained from the national death records. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) for mortality outcomes were estimated using Cox proportional hazards regression analysis.

RESULTS

During a total of 2,060,721.9 person-years of follow-up, 2,020 participants died, with 287 CVD deaths and 963 cancer deaths. Low and high uric acid levels were associated with increased all-cause, CVD, and cancer mortality. The multivariable-adjusted HRs for all-cause mortality in the lowest uric acid categories (<3.5 mg/dl for men and <2.5 mg/dl for women) compared with the sex-specific reference category were 1.58 (95% CI 1.18-2.10) and 1.80 (95% CI 1.10-2.93), respectively. Corresponding HRs in the highest uric acid categories (≥9.5 mg/dl for men and ≥8.5 mg/dl for women) were 2.39 (95% CI 1.57-3.66) and 3.77 (95% CI 1.17-12.17), respectively.

CONCLUSION

In this large cohort study of men and women, both low and high uric acid levels were predictive of increased mortality, supporting a U-shaped association between serum uric acid levels and adverse health outcomes.