Chronic kidney disease mineral bone disorder and health-related quality of life among incident end-stage renal-disease patients

Objective: Our objective was to determine the extent to which chronic kidney disease mineral bone disorder (CKD-MBD) is associated with health-related quality of life among incident dialysis patients. Design: This study's design was a cross-sectional analysis. Setting: This was part of the United States Renal Data System Dialysis Morbidity and Mortality Study (DMMS), Wave 2. Patients: The patients comprised 2590 adult participants in DMMS Wave 2, for whom quality of life and laboratory data were available. Methods: We stratified patients according to their serum concentrations of phosphorus, calcium, and parathyroid hormone (PTH), and compared health-related quality of life as a function of these indicators in analyses adjusted for demographic, clinical, and other laboratory variables. Main Outcome Measures: Main outcome measures included Physical Component Summary (PCS) and Mental Component Summary (MCS) scores, and the Symptom score of the Kidney Disease Quality of Life. Results: Both high and low serum phosphorus concentrations were associated with lower PCS scores (-1.25 to -1.48 points compared with the reference category), as was low PTH (-1.49 points). Low serum phosphorus was associated with more severe symptoms of kidney disease (-3.88 points), but there were no associations between high phosphorus or either extreme of PTH and the Symptom score. Serum calcium concentration and the calcium x phosphorus product were unassociated with PCS or Symptom scores. There were no associations among phosphorus, calcium, or PTH and MCS. Analyses simultaneously controlling for serum phosphorus, calcium, and PTH showed similar results. Conclusion: High and low serum phosphorus and low PTH are associated with slightly poorer self-reported physical functioning. Clinical trials will be necessary to determine whether and to what extent improvement in health status may occur with the correction of selected disorders of mineral metabolism. (C) 2007 by the National Kidney Foundation, Inc.