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Clinical Question:
What is the prevalence of urolithiasis in patients with primary gout?
Bottom Line:
Ultrasonography increased the probability of diagnosing urolithiasis by 50%,
meaning the prevalence of urolithiasis in gout is likely higher than
previously reported. A higher urinary H+ ion concentration was the only
variable associated with urolithiasis. Due to advances in diagnosis of gout
and urolithiasis, as well as biochemical assays, the prevalence and risk
factors for urolithiasis in gout require reassessment.
Reference:
Prevalence and Risk Factors for Urolithiasis in Primary Gout: Is a
Reappraisal Needed? Alvarez-Nemegyei J, Medina-Escobedo M, Villanueva-Jorge
S, Vazquez-Mellado J. J Rheumatol. 2005 Nov;32(11):2189-2191.
Synopsis:
To assess the prevalence and risk factors for urolithiasis in primary gout.
One hundred forty patients with primary gout were studied. Urolithiasis was
defined as a history of urolithiasis, or nephrolithiasis detected via
ultrasonography in patients with no previous record of urolithiasis. Patient
age, duration of gout, presence of tophi, obesity, alcoholism, high blood
pressure, diabetes, hyperlipidemia, family history of urolithiasis, daily
urine output, uricemia, urine pH, FeNa, FeUrate, urine pH/FeUrate index, and
daily urine excretion of urate, sodium, calcium and potassium were compared
between lithiasic and non-lithiasic subjects. Fifty-five (39%; 95% CI 31-47)
patients had urolithiasis, of which 37 (26%) were diagnosed by clinical
history and 18 (13%) by ultrasonography. Patients with a silent kidney stone
diagnosed by ultrasound tended to have shorter evolution of gout. Aside from
urinary H+ ion concentration (lithiasic subjects 5.17 +/- 3.9 microM/l; non-lithiasic
subjects 3.80 +/- 3.01 microM/l; p = 0.02), no difference was found between
lithiasic and non-lithiasic subjects for the other variables studied. |