title: Is residual renal function and better phosphate control in peritoneal dialysis an answer for the lower prevalence of valve calcification compared to hemodialysis patients?
abstract: BACKGROUND
  Cardiac valve calcification (CVC) has long been regarded as a consequence of abnormal calcium-phosphate metabolism in uremic patient associated with increased cardiovascular mortality in this population. We evaluated the association between residual renal function (RRF), phosphate level and valve calcification in peritoneal dialysis (PD) and hemodialysis (HD) patients.
  
  
  METHODS
  We studied 30 stable PD patients (60 % males; mean age 57 ± 12.36 years) and 34 HD patients (58.8 % males; mean age 50.8 ± 10.4 years) on renal replacement therapy (RRT) from 6 up to 36 months. The presence of CVC was assessed by standard bi-dimensional echocardiography. RRF was calculated by standard technique.
  
  
  RESULTS
  Valve calcification was more frequently found in HD compared to PD patients (70.6 vs 29.4 %, p = 0.007). Significantly lower phosphate [1.38 ± 0.41 versus 1.99 ± 0.35 mmol/L (p < 0.0001)], a higher RRF [4.09 ± 2.09 ml/min vs 0.62 ± 0.89 ml/min (p < 0.0001)], and older age [57 ± 12.36 years vs 50.8 ± 10.4 years (p = 0.033)] were observed in PD as compared to HD patients. The logistic regression analysis for the presence of valve calcification when adjusted for age and diabetes, with type of therapy, serum phosphate, RRF, CRP, and serum albumin as variables in the model, revealed significant association between the presence of valve calcification and age and RRF. The correlation between phosphate levels and RRF was even stronger in PD patients than in HD patients (r = -0.704; p = 0.0001) vs (r = -0.502; p = 0.02).
  
  
  CONCLUSIONS
  Our study shows that the residual renal function in PD patients contributes significantly to the maintenance of phosphate balance and may explain the lower prevalence of valve calcification in PD patients compared with HD patients in the period up to first 3 years under renal replacement therapy.
authors.affiliation: Department of Nephrology-Dialysis-Transplantation, UHC "Mother Teresa", Dibra Street Nr 370, Tirana, Albania, meritarroji@yahoo.com.
authors.forename: Merita
authors.initials: M
authors.lastname: Rroji
authors.forename: Saimir
authors.initials: S
authors.lastname: Seferi
authors.forename: Majlinda
authors.initials: M
authors.lastname: Cafka
authors.forename: Elizana
authors.initials: E
authors.lastname: Petrela
authors.forename: Erjola
authors.initials: E
authors.lastname: Likaj
authors.forename: Myftar
authors.initials: M
authors.lastname: Barbullushi
authors.forename: Nestor
authors.initials: N
authors.lastname: Thereska
authors.forename: Goce
authors.initials: G
authors.lastname: Spasovski
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001021:Aortic Valve; D002114:Calcinosis / Q000000981:diagnostic imaging / Q000209:etiology*; D003430:Cross-Sectional Studies; D005260:Female; D006349:Heart Valve Diseases / Q000000981:diagnostic imaging / Q000209:etiology*; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D007676:Kidney Failure, Chronic / Q000150:complications / Q000503:physiopathology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve; D010530:Peritoneal Dialysis / Q000009:adverse effects*; D010710:Phosphates / Q000097:blood*; D006435:Renal Dialysis / Q000009:adverse effects; D014463:Ultrasonography
chemical_list: D010710:Phosphates