Hypouricemia was reported as a risk factor for exercise-induced acute renal injury (EIAKI) and urinary stones. However, the prevalence of kidney diseases among hypouricemic subjects has not been ...evaluated. This study was conducted to clarify the prevalence of hypouricemia and the association of hypouricemia with kidney diseases by using a large-scale Japanese population data.
This study is a retrospective cross-sectional study at the Center for Preventive Medicine, St. Luke's International Hospital, Tokyo, Japan, and Sanin Rousai Hospital, Yonago, Japan. We analyzed the medical records of 90,143 Japanese subjects at the center in St. Luke's International Hospital, Tokyo, and 4,837 subjects in Sanin Rousai Hospital, Yonago, who underwent annual regular health check-up between January 2004 and June 2010. We defined hypouricemia as serum uric acid level of ≤2.0 mg/dL. We checked the medical history of all the study subjects and compared the rates of complications including urinary stones and kidney diseases among those with or without hypouricemia.
The prevalence of hypouricemia was 0.19% in St. Luke's International Hospital, Tokyo, and 0.58% in Sanin Rousai Hospital, Yonago. The prevalence of hypouricemia in women was larger than that in men both in Tokyo (0.31% vs 0.068%, p<0.001) and in Yonago (1.237% vs 0.318%, p<0.001). Among 172 hypouricemic subjects (30 men), the rates of previous urinary stones and kidney diseases (including nephritis/nephrosis) were 1.2% (3.3% men, 0.7% women) and 2.3% (10% men, 0.7% women), respectively. Hypouricemic men had a 9-fold higher rate of previously having kidney diseases compared to non-hypouricemic men (p<0.001). However, the rates of other diseases including urinary stones were not significantly different between the two groups.
Hypouricemia was associated with a history of kidney disease especially in men.
Whether or not extremely low levels of serum uric acid (SUA) in xanthinuria are associated with impairment of the endothelial function and exercise-induced acute kidney injury (EIAKI) is unclear. A ...59-year-old woman without EIAKI or urolithiasis had undetectable levels of UA in serum and urine and elevated levels of hypoxanthine and xanthine in urine. A genetic analysis revealed homozygous mutations in the XDH gene c.1585 C>T (p. Gln529*). Flow-mediated dilation was within the normal range. This is the first report of a case with extremely low levels of SUA, xanthinuria with novel mutations of xanthine dehydrogenase (XDH) and a normal endothelial function.
Renal hypouricemia (RHUC) is a disease caused by dysfunction of renal urate reabsorption transporters; however, diagnostic guidance and guidelines for RHUC have been lacking, partly due to the low ...evidence level of studies on RHUC. This review describes a world-first clinical practice guideline (CPG) and its first version in English for this condition. It was developed following the “MINDS Manual for Guideline Development” methodology, which prioritizes evidence-based medicine. It was published in Japanese in 2017 and later translated into English. The primary goal of this CPG is to clarify the criteria for diagnosing RHUC; another aim is to work towards a consensus on clinical decision-making. One of the CPG’s unique points is that it contains textbook descriptions at the expert consensus level, in addition to two clinical questions and recommendations derived from a systematic review of the literature. The guidance shown in this CPG makes it easy to diagnose RHUC from simple blood and urine tests. This CPG contains almost all of the clinical foci of RHUC: epidemiology, pathophysiology, diagnostic guidance, clinical examinations, differential diagnosis, and complications, including exercise-induced acute kidney injury and urolithiasis. A CPG summary as well as a clinical algorithm to assist healthcare providers with a quick reference and notes from an athlete for both physicians and patients are included. We hope that this CPG will help healthcare providers and patients to make clinical decisions, and that it will promote further research on RHUC.
It has been reported that cardiovascular events often occur on Monday morning, especially in the young working population. Because hypertension is a major cardiovascular risk, we examined whether ...blood pressure was elevated on Monday, especially in the morning during work. However, there were no weekly rhythms in blood pressure itself. Instead, we found significant interactions between the double product (systolic blood pressure × heart rate) and weekly (high on Monday) and circadian (high in the morning) rhythms. Further studies are required to determine whether Monday morning preference in cardiovascular events is caused by increased double product.
Background The relationship between plasma uridine levels and blood pressure (BP), and indicators of muscular purine degradation and insulin resistance (IR) has been evaluated in hypertensive (HT) ...patients. Methods and Results In 36 HT patients and 10 normotensive subjects, seated BP was measured, and blood samples were drawn after overnight fast. In 18 of the HT patients, the semi-ischemic forearm test was performed to examine the release of hypoxanthine, ammonium and lactate. Plasma uridine levels were significantly higher than in the normotensive subjects. Fasting plasma insulin levels and homeostasis model assessment of IR correlated with plasma uridine levels in the HT patients. Plasma uridine levels showed a significant correlation with hypoxanthine, ammonia and lactate released from the semi-ischemic exercising muscles of the HT patients. Conclusions Taken together with the positive correlation with indicators of IR, it is suggested that plasma uridine levels in HT are responsible for purine degradation and IR in skeletal muscles. (Circ J 2007; 71: 354 - 356)
Clinical practice guidelines (CPGs) consist of clinical questions (CQs) and corresponding recommendations. Considering the estimation of body of evidence, patients' opinions, and medical economics, ...recommendations can vary depending on the votes of the committee members of CPGs. Taking this into consideration, concerns have already been raised on how financial conflict of interest (COI) potentially influences recommendations. In this study, we developed the third edition of guideline for the management of hyperuricemia and gout. This CPG was composed of seven CQs and recommendations. The direction and strength of the recommendations were determined by votes. There are three CQs. Individual questions asked whether uric acid-lowering-agents (ULAs) could be applied to hyperuricemic patients with chronic kidney disease (CKD) (CQ A), hypertension (CQ B), or heart failure (CQ C) to prevent organ damage. We examined whether the absence (18 members) or presence (8 members) of COIs of committee members could influence the votes. In total, 26 committee members with and without COI have equally determined the direction and strength of recommendations. In CQ A, members without financial COIs and those with financial COI selected conditional recommendation for the use of ULAs in patients with CKD (without COI, 17/18; with COI, 7/8). In CQ B, members without financial COIs and those with financial COI selected conditional recommendation against the use of ULAs in hypertensive patients (without COI, 14/18; with COI, 5/8). In CQ C, members without financial COIs and those with financial COIs have selected conditional recommendation against the use of ULAs in patients suffering from heart failure (without COI, 15/18; with COI, 4/8).We found that members with financial COIs have determined their recommendations in the same direction and strength as those without financial COIs.
Hyperuricemia and lifestyle-related diseases are often comorbid in the same subjects.Therefore, nutrition education is usually included in the educational program for improvement of their life-style. ...In this study, we investigated retrospectively the effect of nutrition education for the patients of dyslipidemia on their serum uric acid level.Forty-three subjects of dyslipidemia were enrolled. We investigated the data of body weight, serum lipid profiles, serum uric acid level and so on for 1 year after the first education exposure. The average times of nutrition education was 2.5. In the analysis of the all subjects, body weight significantly decreased in 3 and 12 months after the first education compared to before. Serum LDL cholesterol level significantly decreased from 150.9±32.6mg/dl (before education) to 139.0±35.7mg/dl (3 months) and 132.1±31.9mg/dl (12months). Serum uric acid level did not decrease by education in all subjects. In the analysis of non-medicated hyperuricemia subjects, serum uric acid level decreased significantly after the education. In the group of body weight loss tends to decrease serum uric acid level compared with the group of body weight increase.In this study, nutrition education for dyslipidemia subjects may be useful for the improvements of the serum uric acid level. The body weight loss might be a good surrogate goal in the education for the improvement of the life style for the decrease of the serum uric acid level.
Background The angiotensin receptor blocker losartan inhibited urate transporter 1 (URAT1) according to in vitro experiments. However, it is still unknown whether the inhibitory effect of losartan on ...URAT1 contributes to its uricosuric action in humans. Methods Thirty-two patients with hypertension and nine patients with idiopathic renal hypouricemia (five with and four without hypertension) were enrolled for this study. Hypertensive patients were prescribed oral losartan (50 mg/day, n = 16) or candesartan (8 mg/day, n = 16). Before and after 1-month treatment, the serum concentration of urate (Sur) and creatinine (Scr), and the clearance value of urate (Cur) and creatinine (Ccr) were determined. Clearance studies using the URAT1 inhibitor benzbromarone (100 mg/day) or losartan (50 mg/day) loading test were also performed in these patients. Results Blood pressure (BP) significantly decreased in the patients treated with either losartan or candesartan. Losartan significantly reduced Sur, which was associated with a concomitant increase in the Cur/Ccr ratio, whereas candesartan did not alter these parameters. In hypertensive patients with loss-of-function mutation of URAT1, losartan did not alter either Sur or Cur/Ccr, nor did benzbromarone. The lack of effect of URAT1 inhibitors on renal excretion of urate was independent of the renal function of hypouricemic patients. On the other hand, both losartan and benzbromarone increased Cur/Ccr ratio in hypertensive patients harboring the wild URAT1 gene, regardless of the presence of hypouricemia. Conclusions These findings suggested that losartan inhibited URAT1 and thereby it lowered Sur levels in hypertensive patients.
Objective The acute effects of the angiotensin II receptor antagonist losartan on uric acid and oxypurine metabolism were evaluated. Methods Losartan (50 mg) was administered orally to 6 healthy ...males. Blood and urine samples for uric acid and oxypurine were collected before and up to 6 hours after losartan administration. The same examinations were performed later using enalapril (5 mg). Results Losartan decreased the serum uric acid concentration (from 5.9±0.9 to 5.2±1.0 mg/dl) and increased its fractional clearance, which reached a maximum after 2 hours, while enalapril did not. Losartan also induced an increase in the plasma concentration of hypoxanthine, peaking in the fourth hour, and a decrease in its urinary clearance, while the plasma xanthine concentration and its urinary clearance were unchanged. The extent of uric acid excretion was much greater than that of the oxypurines. Conclusions Losartan, which has a high affinity for the urate/anion exchanger, has a transient uricosuric effect. Our data indicate that losartan induces a significant decrease in the urinary excretion of hypoxanthine without changes in xanthine. (Internal Medicine 41: 793-797, 2002)
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