title: A New Data Analysis System to Quantify Associations between Biochemical Parameters of Chronic Kidney Disease-Mineral Bone Disease.
abstract: BACKGROUND
  In hemodialysis patients, deviations from KDIGO recommended values of individual parameters, phosphate, calcium or parathyroid hormone (PTH), are associated with increased mortality. However, it is widely accepted that these parameters are not regulated independently of each other and that therapy aimed to correct one parameter often modifies the others. The aim of the present study is to quantify the degree of association between parameters of chronic kidney disease and mineral bone disease (CKD-MBD).
  
  
  METHODS
  Data was extracted from a cohort of 1758 adult HD patients between January 2000 and June 2013 obtaining a total of 46.141 records (10 year follow-up). We used an advanced data analysis system called Random Forest (RF) which is based on self-learning procedure with similar axioms to those utilized for the development of artificial intelligence. This new approach is particularly useful when the variables analyzed are closely dependent to each other.
  
  
  RESULTS
  The analysis revealed a strong association between PTH and phosphate that was superior to that of PTH and Calcium. The classical linear regression analysis between PTH and phosphate shows a correlation coefficient is 0.27, p<0.001, the possibility to predict PTH changes from phosphate modification is marginal. Alternatively, RF assumes that changes in phosphate will cause modifications in other associated variables (calcium and others) that may also affect PTH values. Using RF the correlation coefficient between changes in serum PTH and phosphate is 0.77, p<0.001; thus, the power of prediction is markedly increased. The effect of therapy on biochemical variables was also analyzed using this RF.
  
  
  CONCLUSIONS
  Our results suggest that the analysis of the complex interactions between mineral metabolism parameters in CKD-MBD may demand a more advanced data analysis system such as RF.
authors.affiliation: Nephrology Service, Hospital Reina Sofia, IMIBIC, University of Cordoba, Cordoba, Spain.
authors.forename: Mariano
authors.initials: M
authors.lastname: Rodriguez
authors.affiliation: Nephrology Service, Hospital Reina Sofia, IMIBIC, University of Cordoba, Cordoba, Spain.
authors.forename: M Dolores
authors.initials: MD
authors.lastname: Salmeron
authors.affiliation: Nephrology Service, Hospital Reina Sofia, IMIBIC, University of Cordoba, Cordoba, Spain.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Martin-Malo
authors.affiliation: Fresenius Medical Care, Bad Homburg, Germany.
authors.forename: Carlo
authors.initials: C
authors.lastname: Barbieri
authors.affiliation: Fresenius Medical Care, Bad Homburg, Germany.
authors.forename: Flavio
authors.initials: F
authors.lastname: Mari
authors.affiliation: Nephrology Service, Hospital Reina Sofia, IMIBIC, University of Cordoba, Cordoba, Spain.
authors.forename: Rafael I
authors.initials: RI
authors.lastname: Molina
authors.affiliation: Fresenius Medical Care, Madrid, Spain.
authors.forename: Pedro
authors.initials: P
authors.lastname: Costa
authors.affiliation: Nephrology Service, Hospital Reina Sofia, IMIBIC, University of Cordoba, Cordoba, Spain.
authors.forename: Pedro
authors.initials: P
authors.lastname: Aljama
mesh_terms: D000328:Adult; D000368:Aged; D001847:Bone Diseases / Q000097:blood* / Q000150:complications; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D010710:Phosphates / Q000097:blood*; D006435:Renal Dialysis; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000150:complications / Q000628:therapy; D013223:Statistics as Topic
chemical_list: D010281:Parathyroid Hormone; D010710:Phosphates