Tumoural hypouricemia

Hypouricemia in the emergency department: A retrospective, single-center study

Backgrounds

Few studies have reported the prevalence and characteristics of hypouricemia in the emergency department (ED). We investigated the prevalence and characteristics of hypouricemia in the ED of a university-affiliated hospital in Japan.

Methods

This is a retrospective cross-sectional single-center study. All adult patients (18 years old or older) who had their serum uric acid (SUA) measured at the ED between 2011 and 2021 were included. Information collected included age, sex, SUA, and serum creatinine. Hypouricemia was defined as an SUA level ≦2.0 mg/dL.

Results

A total of 10,551 patients were included in the study. Fifty-one percent were male. The median SUA levels were significantly higher in men than in women (6.0 [4.8-7.4] vs. 4.7 [3.7-6.1], p < 0.001). The prevalence of hypouricemia was higher in women than in men (2.0% vs. 0.9%, p < 0.001). A possible cause of hypouricemia was identified in 88 patients. Malignancy and diabetes were the major possible cause of hypouricemia (p < 0.001).

Conclusion

The distribution of SUA levels and prevalence of hypouricemia differed significantly by sex and age in the ED. Malignancy was the leading cause of hypouricemia in the ED.

Serum Uric Acid Revealed a U-Shaped Relationship With All-Cause Mortality and Cardiovascular Mortality in High Atherosclerosis Risk Patients: The ASSURE Study

Background: Previous studies have demonstrated an association between hyperuricemia and cardiovascular disease (CVD). The Framingham study confirmed that patients with high atherosclerotic risks (HARs) had worse prognoses. However, after adjusting for confounding factors, the association between serum uric acid (SUA) and all-cause mortality and cardiovascular mortality remains unclear, especially for HAR patients. Objective: The aim of this study was to reveal the relationship of SUA with all-cause and cardiovascular mortality in HAR patients. Methods: This multicenter cohort study enrolled 3,047 participants, and the follow-up was 68.85 ± 11.37 months. Factors related to cardiovascular and all-cause mortality were tested by multivariate Cox regression analysis. Restricted cubic splines (RCSs) with knots were used to explore the shape of the dose-response relationship with SUA and the hazard ratio (HR) of all-cause and CVD mortality. SUA transformed by RCS was added to the Cox regression model as an independent variable, and all-cause and CVD mortality scores were calculated. Survival receiver operating characteristic curves were produced using a regression model predicting the score. Results: SUA demonstrated a "U-shaped" relationship with all-cause and cardiovascular mortality. SUA predicted all-cause and CVD mortality, with cutoff values of values of >370.5 μmol/L for males and >327.65 μmol/L for females and <180.5 μmol/L for males and <165.7 μmol/L for females, respectively. The survival ROC curve indicated that SUA is able to predict all-cause and CVD mortality, with areas under the curve of 0.702 and 0.711, respectively. The HRs of all-cause mortality (male and female) with hyperuricemia and hypouricemia were 2.08 and 2.01 and 2.04 and 1.98, respectively, and the HRs of CVD mortality (male and female) were 2.09 and 1.79, and 2.02 and 1.89, respectively. Conclusion: Abnormal SUA levels were significant and independent risk factors for all-cause and CVD mortality. Hyperuricemia and hypouricemia increased mortality in both males and females. Routine SUA evaluation and intensive management are needed for HAR patients. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT03616769.

Prevalence and possible causes of hypouricemia at a tertiary care hospital

BACKGROUND/AIMS

We aimed to investigate the prevalence and possible causes of hypouricemia in the Korean population and to compare our findings with published results of other populations.

METHODS

We examined the serum uric acid levels of 30,757 subjects who had their uric acid values measured at least once during a 1-year period. All individuals with hypouricemia (serum uric acid < 2.0 mg/dL, n = 424) were reviewed with respect to medical drug history and concomitant diseases previously identified as being associated with hypouricemia.

RESULTS

The prevalence of hypouricemia was 4.14% (299/7,223) among inpatients and 0.53% (125/23,534) among outpatients, for an overall prevalence of 1.39% (424/30,757). Possible causes associated with hypouricemia were found to be solid or hematologic malignancies (n = 86), diabetes mellitus (n = 56), and therapeutic drugs (n = 29). The medications were allopurinol (n = 11), angiotensin II receptor blockers (n = 10), salicylates (n = 6), febuxostat (n = 1), and warfarin (n = 1). In the remaining 226 individuals, the cause of hypouricemia was not identified.

CONCLUSIONS

Hypouricemia is relatively common in the Korean population compared to those of other countries. The possible causes associated with hypouricemia are related to underlying diseases and medications.

[Hypouricemia, an old subject and new concepts]

DEFINITION OF HYPOURICEMIA: Hypouricemia (serum uric acid less than 120 micro mol/l) is a biological abnormality often discovered accidentally and with a low prevalence depending on its permanent or transitory nature ranging from 0.15 to 3.38%. NEW PHYSIOLOGICAL CONCEPTS OF ITS PATHOGENESIS: Recently, our knowledge of the physiopathological mechanisms of hypouricemia has been emphasized by the identification of three systems of renal and extra-renal uric acid transport: a Cl/urate (URAT1) transporter, a multispecific organic anion transporter (OAT) and a urate transporter/channel. ETIOLOGY AND COMPLICATIONS OF HYPOURICEMIA: Through questioning, drugs and toxics (allopurinol.) are generally rapidly recognized as responsible for half of the hypouricemia encountered. It can be concomitant to a known disease: severe liver disease, neoplasia, diabetes, AIDS, syndrome of inappropriate antidiuretic hormone secretion. Hypouricemia can also be isolated and justifies the measurement of uric acid clearance, the normality or reduction of which orients towards a deficiency in xanthine-oxydase, the increase in which suggests an abnormality in uric acid transport in the proximal tubule (Fanconi syndrome, primary hereditary anomaly of tubular uric acid transport). Hypouricemia does not appear to expose the patient to any danger, but the onset of nephrolithiasis or acute renal failure secondary to the combination of severe hypouricemia and oxidant stress is always possible.

Hypouricemia in individuals admitted to an inpatient hospital-based facility

BACKGROUND

Decreased serum uric acid levels resulting from renal urate wasting occasionally are reported in hospitalized patients because of isolated or generalized proximal tubular damage. There are limited recent findings with regard to the incidence and cause of hypouricemia in patients admitted to an internal medicine clinic. The aim of this study is to examine the prevalence of hypouricemia in individuals admitted to our inpatient hospital-based facility and identify underlying causes and pathogenetic mechanisms and any association of hypouricemia and uricosuria with other tubular defects.

METHODS

A total of 7,250 serum urate measurements were available on patients' admission. Hypouricemia is defined as a serum urate level less than 2.5 mg/dL (149 micromo/L). In all hypouricemic cases, a detailed clinical and laboratory investigation was performed.

RESULTS

Hypouricemia was found in 90 patients (1.24%). In all except one patient, hypouricemia was associated with inappropriate uricosuria (urate fractional excretion [FE] > 10%; range, 10.8% to 94%). There was an inverse correlation between serum uric acid level and its FE (r = -0.73; P < 0.0001). The most common causes of hypouricemia were obstructive jaundice of any cause (n = 18), solid or hematologic neoplasias (n = 17), diabetes mellitus (n = 12), drugs affecting urate homeostasis (n = 10), and intracranial diseases (n = 8). Seventeen patients with hypouricemia showed one or more other manifestations of proximal tubular damage, such as glucosuria, inappropriate phosphaturia leading to hypophosphatemia, and kaliuria resulting in hypokalemia.

CONCLUSION

Hypouricemia caused by inappropriate uricosuria is not rare in patients admitted to an internal medicine clinic, is related to underlying diseases, and may be associated with other abnormalities of proximal tubular function.