title: Use of the probability of stone formation (PSF) score to assess stone forming risk and treatment response in a cohort of Brazilian stone formers.
abstract: BACKGROUND
  The aim was to confirm that PSF (probability of stone formation) changed appropriately following medical therapy on recurrent stone formers.
  
  
  METHODS
  Data were collected on 26 Brazilian stone-formers. A baseline 24-hour urine collection was performed prior to treatment. Details of the medical treatment initiated for stone-disease were recorded. A PSF calculation was performed on the 24 hour urine sample using the 7 urinary parameters required: voided volume, oxalate, calcium, urate, pH, citrate and magnesium. A repeat 24-hour urine sample was performed for PSF calculation after treatment. Comparison was made between the PSF scores before and during treatment.
  
  
  RESULTS
  At baseline, 20 of the 26 patients (77%) had a high PSF score (> 0.5). Of the 26 patients, 17 (65%) showed an overall reduction in their PSF profiles with a medical treatment regimen. Eleven patients (42%) changed from a high risk (PSF > 0.5) to a low risk (PSF < 0.5) and 6 patients reduced their risk score but did not change risk category. Six (23%) patients remained in a high risk category (> 0.5) during both assessments.
  
  
  CONCLUSIONS
  The PSF score reduced following medical treatment in the majority of patients in this cohort.
authors.affiliation: Department of Urology, University of Oxford, Oxford; United Kingdom.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Turney
authors.affiliation: Deparment of Urolithiasis Research, Cambridge University Hospitals Trust, Cambridge, United Kingdom.
authors.forename: William
authors.initials: W
authors.lastname: Robertson
authors.affiliation: Department of Urology, Cambridge University Hospitals Trust, Cambridge, United Kingdom.
authors.forename: Oliver
authors.initials: O
authors.lastname: Wiseman
authors.affiliation: Department of Urinary, Lithiasis Metabolism Service, School of Medicine, São Paulo State University (UNESP), Botucatu, SP, Brazil.
authors.forename: Carmen Regina P R
authors.initials: CR
authors.lastname: Amaro
authors.affiliation: Department of Urology, School of Medicine, São Paulo State University (UNESP), Botucatu, SP, Brazil.
authors.forename: Victor A
authors.initials: VA
authors.lastname: Leitão
authors.affiliation: Department of Urinary, Lithiasis Metabolism Service, School of Medicine, São Paulo State University (UNESP), Botucatu, SP, Brazil.
authors.forename: Isabela Leme da
authors.initials: IL
authors.lastname: Silva
authors.affiliation: Department of Urology, School of Medicine, São Paulo State University (UNESP), Botucatu, SP, Brazil.
authors.forename: João Luiz
authors.initials: JL
authors.lastname: Amaro
mesh_terms: D000328:Adult; D000368:Aged; D002130:Calcium Phosphates / Q000652:urine; D002951:Citrates / Q000652:urine; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008274:Magnesium / Q000652:urine; D008297:Male; D008875:Middle Aged; D010070:Oxalates / Q000652:urine; D011336:Probability; D012016:Reference Values; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014527:Uric Acid / Q000652:urine; D052878:Urolithiasis / Q000209:etiology / Q000473:pathology / Q000628:therapy* / Q000652:urine*
chemical_list: D002130:Calcium Phosphates; D002951:Citrates; D010070:Oxalates; D014527:Uric Acid; C020243:calcium phosphate; D008274:Magnesium