The importance of serum albumin and phosphorous as predictors of mortality in ESRD patients.

Secondary hyperparathyroidism and abnormal calcium/phosphate balance are common complications of ESRD and significant cardiovascular risk factors. It has also been demonstrated that malnourished dialysis patients have a much higher mortality than well-nourished patients. There is a lack of research looking at combined mortality with altered mineral metabolism and a low serum albumin. Using our renal database, we analyzed outcomes on 1,007 chronic dialysis patients, commencing dialysis between January 1990 and December 2004. The association between median values of serum phosphate, calcium, albumin (between three and six months post-commencement of dialysis), and long-term survival was examined. Cox proportional hazards models were used to determine the combined effects of these variables on patient outcome. The results showed that 18% of patients had serum phosphorous >1.8 mmol/L (5.5 g/dL), and the five-year survival of these patients was 48.4% compared with 58.6% for those with a serum phosphorous <1.8 mmol/L (p = 0.047). For serum albumin, 34.9% had a value <35 g/L, and this group also had a highly significant risk of increased mortality (p < 0.001). When combined with corrected calcium, 40.9% of patients reached all three target levels and had the greatest long-term survival (five-year survival of 62.5% for all three targets reached, compared to 30.7% for 0 or 1 targets reached). Poor control of calcium/phosphorous balance appears to have long-term deleterious effects on patient survival in ESRD patients. This risk of death is increased by poor serum albumin levels reflecting inadequate nutrition.