Characteristic clinical and biochemical profile of recurrent calcium-oxalate nephrolithiasis in patients with metabolic syndrome.
BACKGROUND
Metabolic syndrome is a risk factor for nephrolithiasis. This study was performed to evaluate the clinical and biochemical profile of calcium-oxalate nephrolithiasis in stone formers with metabolic syndrome.


METHODS
A total of 526 recurrent stone formers, 184 of them with metabolic syndrome, and 214 controls were examined on a free diet and after a sodium-restricted diet (sodium intake < 100 mmol/24 h).


RESULTS
On free diet, stone formers with metabolic syndrome showed higher sodium excretion [mean (95% confidence interval), 196 (176-218) vs 160 (150-168) mmol/24 h; P < 0.01] and lower citrate excretion [2.23 (1.99-2.58) vs 2.84 (2.51-3.17) mmol/24 h; P < 0.01] compared to controls, whereas stone formers without metabolic syndrome showed higher calcium and oxalate excretion [5.43 (5.01-5.82) vs 3.58 (2.84-4.19) and 0.34 (0.32-0.36) vs 0.26 (0.20-0.31)m mmol/24 h for calcium and oxalate, respectively; P < 0.01] and lower citrate excretion [2.18 (1.98-2.38) vs 2.84 (2.51-3.17) mmol/24 h; P < 0.01] compared to controls. The ion activity product of urinary calcium-oxalate salts was similar between stone formers with and without metabolic syndrome [1.41 (1.31-1.59) vs 1.40 (1.35-1.45); P > 0.05]. After the test diet, this index was lower in diet-compliant stone formers with metabolic syndrome compared to diet-compliant stone formers without metabolic syndrome [1.15 (1.10-1.21) vs 1.39 (1.31-1.45); P < 0.01].


CONCLUSIONS
The biochemical profiles and responses to the sodium-restricted diet were significantly different between stone formers with metabolic syndrome and those without. Dietary habits play a central role in the pathogenesis of nephrolithiasis in stone formers with metabolic syndrome.
Departament of Radiology, Hospital Universitario Insular de Gran Canaria, Spain. domenico.rendina@unina.it
Domenico
D
Rendina
Gianpaolo
G
De Filippo
Giorgia
G
Zampa
Riccardo
R
Muscariello
Giuseppe
G
Mossetti
Pasquale
P
Strazzullo
D000328:Adult; D002118:Calcium / Q000378:metabolism*; D002129:Calcium Oxalate / Q000737:chemistry*; D004039:Diet, Sodium-Restricted; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006801:Humans; D007677:Kidney Function Tests; D008297:Male; D024821:Metabolic Syndrome / Q000150:complications*; D008875:Middle Aged; D053040:Nephrolithiasis / Q000209:etiology*; D010070:Oxalates / Q000378:metabolism*; D011379:Prognosis; D012008:Recurrence; D012307:Risk Factors
D010070:Oxalates; D002129:Calcium Oxalate; D002118:Calcium