title: Clinical and biochemical differences in patients with pure calcium oxalate monohydrate and calcium oxalate dihydrate kidney stones.
abstract: To examine the factors and patient characteristics predisposing to formation of calcium oxalate monohydrate or calcium oxalate dihydrate kidney stones, we compared blood and 24-hour urine tests, gender distribution and patient age in 2 groups of patients with pure calcium oxalate monohydrate (422) and calcium oxalate dihydrate (68) stones treated at the lithotripsy unit of the Wellesley Hospital and University of Toronto during 4 years. The calcium oxalate monohydrate group included relatively more women (31% versus 16% in the calcium oxalate dihydrate group, chi-square 7.89, p = 0.005). Patients were older in the calcium oxalate monohydrate group (59 +/- 13 versus 51 +/- 13 years, p = 0.001). The calcium oxalate monohydrate group had lower urinary calcium (4.19 +/- 2.34 versus 7.19 +/- 3.38 mmol. per day, p < 0.0001), calcium oxalate relative saturation rate (6.9 +/- 3.9 versus 8.9 +/- 3.3, p = 0.001), brushite relative saturation rate (0.7 +/- 0.8 versus 1.2 +/- 0.9, p = 0.0001) and urinary pH (5.72 +/- 0.75 versus 5.93 +/- 0.72). When corrected for patient age and gender, the calcium oxalate dihydrate group still had higher urine calcium levels. Higher urine pH in the calcium oxalate dihydrate group was age-related. In summary, we present evidence that calcium oxalate dihydrate stones are relatively more common among younger male patients with higher urine calcium levels and higher urine pH.
authors.affiliation: Division of Nephrology, Wellesley Hospital, Toronto, Ontario, Canada.
authors.forename: A E
authors.initials: AE
authors.lastname: Pierratos
authors.forename: H
authors.initials: H
authors.lastname: Khalaff
authors.forename: P T
authors.initials: PT
authors.lastname: Cheng
authors.forename: K
authors.initials: K
authors.lastname: Psihramis
authors.forename: M A
authors.initials: MA
authors.lastname: Jewett
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D002129:Calcium Oxalate / Q000652:urine*; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000652:urine*; D008297:Male; D008875:Middle Aged; D012737:Sex Factors
chemical_list: D002129:Calcium Oxalate