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.


CONCLUSIONS
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.
Bairaktari
Eleni T
ET
Department of Internal Medicine, University Hospital, University of Ioannina, Medical School, Ioannina, Greece.
Kakafika
Anna I
AI
Pritsivelis
Nikos
N
Hatzidimou
Katerina G
KG
Tsianos
Epameinondas V
EV
Seferiadis
Konstantin I
KI
Elisaf
Moses S
MS
D001786:Blood Glucose / Q000032:analysis; D003920:Diabetes Mellitus / Q000097:blood / Q000652:urine; D006029:Glycosuria / Q000453:epidemiology; D019337:Hematologic Neoplasms / Q000097:blood / Q000652:urine; D006748:Hospital Departments / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D015212:Inflammatory Bowel Diseases / Q000652:urine; D007297:Inpatients; D007388:Internal Medicine; D041781:Jaundice, Obstructive / Q000097:blood / Q000652:urine; D007687:Kidney Tubules, Proximal / Q000503:physiopathology*; D007922:Leptospirosis / Q000652:urine; D010710:Phosphates / Q000652:urine; D011188:Potassium / Q000652:urine; D012189:Retrospective Studies; D014527:Uric Acid / Q000097:blood* / Q000652:urine
D001786:Blood Glucose; D010710:Phosphates; D014527:Uric Acid; D011188:Potassium