title: Biochemical determinants of severe lithogenic activity in patients with idiopathic calcium nephrolithiasis.
abstract: OBJECTIVE
  To analyze the biochemical alterations in plasma and the urine determinants of severe lithogenic activity in patients with idiopathic calcium nephrolithiasis.
  
  
  METHODS
  We performed a cross-sectional study of 120 patients divided into 2 groups: group 1, 60 patients without nephrolithiasis; and group 2, 60 patients with severe and/or recurrent calcium nephrolithiasis. In all patients, a study of renal function, calcium metabolism, and bone remodeling markers, and a study of the lithogenic factors were performed in urine after fasting and in 24-hour urine samples.
  
  
  RESULTS
  We observed greater values for phosphorus in group 1 than in group 2 (P=.03). Also, we found greater values for intact parathyroid hormone (P=.01), osteocalcin (P=.000), and β-crosslaps (P=.000) in group 2 than in group 1. In the 24-hour urine samples, significant differences were found between groups 1 and 2 in calciuria (11.7 vs 17.4 mg/dL; P=.000), citraturia (50.6 vs 33.5 mg/dL; P=.002), calcium/creatinine quotient (0.14 vs 0.20; P=.001), calcium/citrate quotient (0.05 vs 0.13; P=.04), and calcium/creatinine quotient after fasting (0.09 vs 0.16; P=.000).
  
  
  CONCLUSIONS
  We consider the determinants of severe and/or recurrent calcium lithiasis to be hypercalciuria and hypocitraturia and a calcium/citrate quotient>0.06. As risk markers we can consider phosphatemia<2.9 mg/dL, phosphate/chlorine quotient>35, alkaline phosphatase>80 U/L, intact parathyroid hormone>60 pg/mL, osteocalcin>16 ng/mL, β-crosslaps>0.400 ng/mL, and β-crosslaps/osteocalcin quotient>0.028.
authors: Department of Urology, San Cecilio University Hospital, Granada, Spain. arrabalp@ono.com
authors: Miguel Angel
authors: MA
authors: Arrabal-Polo
authors: Miguel
authors: M
authors: Arrabal-Martin
authors: Tomas
authors: T
authors: de Haro-Muñoz
authors: Antonio
authors: A
authors: Poyatos-Andujar
authors: Francisco
authors: F
authors: Palæo-Yago
authors: Armando
authors: A
authors: Zuluaga-Gomez
mesh_terms: D000328:Adult; D017677:Age Distribution; D015415:Biomarkers / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007669:Kidney Calculi / Q000737:chemistry / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D053040:Nephrolithiasis / Q000175:diagnosis* / Q000453:epidemiology*; D015675:Osteocalcin / Q000378:metabolism; D010281:Parathyroid Hormone / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism*; D011379:Prognosis; D012008:Recurrence; D018570:Risk Assessment; D012720:Severity of Illness Index; D017678:Sex Distribution; D013030:Spain
chemical_list: D015415:Biomarkers; D010281:Parathyroid Hormone; D015675:Osteocalcin; D010758:Phosphorus; D002118:Calcium