title: Comparison of the metabolic profile of mixed calcium oxalate/uric acid stone formers to that of pure calcium oxalate and pure uric acid stone formers.
abstract: OBJECTIVE
  To compare the metabolic profile of patients who form mixed calcium oxalate (CaOx)/uric acid (UA) stones to those of pure CaOx and pure UA stone formers.
  
  
  METHODS
  We performed a retrospective review of 232 patients, with both stone composition analysis and 24-hour urine collection, seen between March 2002 and April 2012. Analysis of 24-hour urine constituents across the 3 stone groups (pure UA, pure CaOx, and mixed CaOx/UA) was performed using univariate analysis of variance and multivariate linear regression models adjusting for clinical and demographic factors and 24-hour urine collection elements.
  
  
  RESULTS
  A total of 27 patients (11.6%) had mixed CaOx/UA, 122 (52.6%) had pure CaOx, and 83 (35.8%) had pure UA calculi. Univariate analysis demonstrated significant differences between mixed CaOx/UA patients and pure CaOx patients for urine pH (mixed, 5.63 ± 0.49 vs pure, CaOx 5.93 ± 0.51; P = .009) and supersaturation (SS) UA (mixed, 1.84 ± 1.09 vs pure, CaOx 1.26 ± 0.93; P = .01), and a significant difference between mixed CaOx/UA patients and pure UA patients for SS CaOx (mixed, 7.18 ± 4.23 vs pure, UA 4.90 ± 2.96; P = .005). Multivariate analysis demonstrated that mixed CaOx/UA patients had no significant difference in SS CaOx as compared with pure CaOx patients (difference, -0.27; P = .66), whereas at the same time had no significant difference in SS UA as compared with pure UA patients (-0.07; P = .69).
  
  
  CONCLUSIONS
  The metabolic profile of patients who form mixed CaOx/UA stones demonstrates abnormalities that promote both CaOx and UA stone formation. Dietary and medical management for this group of patients should address treatment of both defects.
authors.affiliation: Department of Urology, UT Southwestern Medical Center, Dallas, TX; The Arthur Smith Institute for Urology, Hofstra North Shore-LIJ School of Medicine at Hofstra University, New Hyde Park, NY. Electronic address: justinfriedlander@gmail.com.
authors.forename: Justin I
authors.initials: JI
authors.lastname: Friedlander
authors.affiliation: The Arthur Smith Institute for Urology, Hofstra North Shore-LIJ School of Medicine at Hofstra University, New Hyde Park, NY.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Moreira
authors.affiliation: The Arthur Smith Institute for Urology, Hofstra North Shore-LIJ School of Medicine at Hofstra University, New Hyde Park, NY.
authors.forename: Christopher
authors.initials: C
authors.lastname: Hartman
authors.affiliation: The Arthur Smith Institute for Urology, Hofstra North Shore-LIJ School of Medicine at Hofstra University, New Hyde Park, NY.
authors.forename: Sammy E
authors.initials: SE
authors.lastname: Elsamra
authors.affiliation: The Arthur Smith Institute for Urology, Hofstra North Shore-LIJ School of Medicine at Hofstra University, New Hyde Park, NY.
authors.forename: Arthur D
authors.initials: AD
authors.lastname: Smith
authors.affiliation: The Arthur Smith Institute for Urology, Hofstra North Shore-LIJ School of Medicine at Hofstra University, New Hyde Park, NY.
authors.forename: Zeph
authors.initials: Z
authors.lastname: Okeke
mesh_terms: D002129:Calcium Oxalate / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014527:Uric Acid / Q000378:metabolism*; D014545:Urinary Calculi / Q000378:metabolism*
chemical_list: D002129:Calcium Oxalate; D014527:Uric Acid