Impact of longer term phosphorus control on cardiovascular mortality in hemodialysis patients using an area under the curve approach: results from the DOPPS.

BACKGROUND: Serial assessment of phosphorus is currently recommended by the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines, but its additional value versus a single measurement is uncertain. METHODS: We studied data from 17 414 HD patients in the Dialysis Outcomes and Practice Patterns Study, a prospective cohort study, and calculated the area under the curve (AUC) by multiplying the time spent with serum phosphorus >4.5 mg/dL over a 6-month run-in period by the extent to which this threshold was exceeded. We estimated the association between the monthly average AUC and cardiovascular (CV) mortality using Cox regression. We formally assessed whether AUC was a better predictor of CV mortality than other measures of phosphorus control according to the Akaike information criterion. RESULTS: Compared with the reference group of AUC = 0, the adjusted hazard ratio (HR) of CV mortality was 1.12 [95% confidence interval (CI) 0.90-1.40] for AUC > 0-0.5, 1.26 (95% CI 0.99-1.62) for AUC > 0.5-1, 1.44 (95% CI 1.11-1.86) for AUC > 1-2 and 2.03 (95% CI 1.53-2.69) for AUC > 2. The AUC was predictive of CV mortality within strata of the most recent phosphorus level and had a better model fit than other serial measures of phosphorus control (mean phosphorus, months out of target). CONCLUSIONS: We conclude that worse phosphorus control over a 6-month period was strongly associated with CV mortality. The more phosphorus values do not exceed 4.5 mg/dL the better is survival. Phosphorus AUC is a better predictor of CV death than the single most recent phosphorus level, supporting with real-world data KDIGO's recommendation of serial assessment of phosphorus to guide clinical decisions.

Achievement of recommended treatment targets for bone and mineral metabolism in haemodialysis patients using paricalcitol: an observational study.

OBJECTIVE: Secondary hyperparathyroidism (SHPT) is a common problem among patients with chronic kidney disease (CKD) on haemodialysis. This study was conducted to assess the use, effectiveness and safety of intravenous paricalcitol in haemodialysis patients with various degrees of SHPT. MATERIAL AND METHODS: This observational, multicentre, prospective study was conducted in 14 Swedish dialysis centres from May 2007 to June 2008 and included 92 haemodialysis patients with a diagnosis of SHPT associated with CKD. The decision to initiate treatment with intravenous paricalcitol was made by the treating physician. No treatment algorithms were provided. RESULTS: Mean patient age was 64 years. Of the 92 patients included, 74 had an intact parathyroid hormone (iPTH) level of >300 pg/ml at baseline. Median iPTH was 584 pg/ml in patients with a baseline PTH of >300 pg/ml. During follow-up there was a decrease in iPTH to 323 pg/ml at 6 months (-45%, p < 0.0001). In parallel, there was a small increase in serum calcium, but serum phosphorus and the calcium × phosphorus product remained unchanged. CONCLUSIONS: This study showed that intravenous paricalcitol substantially and safely decreased iPTH in haemodialysis patients with a baseline iPTH above the Kidney Disease Outcomes Quality Initiative recommended target range (150-300 pg/ml) and had minimal impact on serum minerals.