Predictors of first ischemic lower limb ulcer in dialysis patients: an observational cohort study.

BACKGROUND: Lower limb ischemia affects the quality of life, physical activity and life expectancy of dialysis patients. The aim of this study was to investigate the risk factors associated with ischemic foot ulcers considering clinical, laboratory and therapeutic domains. METHODS: This observational cohort study was based on data from the Nephrology and Dialysis Department database of Alessandro Manzoni Hospital, Lecco (Italy). All of the incident patients who started dialysis between 1 January 1999 and 29 February 2012 were enrolled, excluding temporary guests, patients with acute renal failure and patients with previous limb ischemia or amputation. Multivariate Cox regression analysis identified the predictors in each domain, which were matched in the final model. A time-dependent approach was used to take into account the evolution of some of the prognostic covariates. RESULTS: Of the 526 incident dialysis patients, 120 developed a lower limb ischemic lesion after a median of 13 months. The incidence of new ulcers was constant during the study period (6 per 100 person-years), but higher in the diabetics with a relative rate of 4.5. The variables significantly related to an increased risk of lower limb ulcers were age, male gender, diabetes, ischemic heart disease, treatment with proton pump inhibitors, iron, anticoagulants and calcium-based binders, and blood levels of phosphorus, triglycerides and C-reactive protein. CONCLUSION: The incidence of lower limb ulcers was highest during the early dialysis follow-up and was associated with, in addition to diabetes, modifiable laboratory and therapeutic predictors such as anticoagulants, proton pump inhibitors, calcium-containing binders, calcimimetics and iron.

Cinacalcet hydrochloride: calcimimetic for the treatment of hyperparathyroidism.

Mineral metabolism disorders, including those related to secondary hyperparathyroidism, affect a large number of patients with chronic kidney disease and are associated with increased relative risk of morbidity and mortality in hemodialysis patients. The traditional therapy of secondary hyperparathyroidism based on vitamin D compounds and calcium-based phosphate binders is often limited by the increase of serum calcium and phosphorus levels limiting the dose that can be given safely, and thus, preventing the attainment of treatment targets. Cinacalcet hydrochloride (Sensipar®, Mimpara®, Parareg®) is the first in a new class of therapeutic agents, the calcimimetics, that increase the sensitivity of calcium-sensing receptors to the extracellular calcium ions, thus lowering parathyroid hormone production and release, decreasing serum calcium and phosphorous concentrations simultaneously. Different randomized, double-blind, placebo-controlled trials evaluated the safety and ability of cinacalcet hydrochloride treatment to improve achievement of target levels of parathyroid hormone, calcium, phosphorus and calcium phosphorus product in dialysis patients. Cinacalcet hydrochloride has also demonstrated to be effective in reducing parathyroid hormone and serum calcium concentrations in patients with primary hyperparathyroidism. On the basis of available data, calcimimetics represent an important innovation and will change the management of mineral metabolism disorders in patients with chronic kidney disease and primary hyperparathyroidism.

Ionic dialysance allows an adequate estimate of urea distribution volume in hemodialysis patients.

BACKGROUND: An adequate estimation of urea distribution volume (V) in hemodialysis patients is useful to monitor protein nutrition. Direct dialysis quantification (DDQ) is the gold standard for determining V, but it is impractical for routine use because it requires equilibrated postdialysis plasma water urea concentration. The single pool variable volume urea kinetic model (SPVV-UKM), recommended as a standard by Kidney Disease Outcomes Quality Initiative (K/DOQI), does not need a delayed postdialysis blood sample but it requires a correct estimate of dialyser urea clearance. METHODS: Ionic dialysance (ID) may accurately estimate dialyzer urea clearance corrected for total recirculation. Using ID as input to SPVV-UKM, correct V values are expected when end-dialysis plasma water urea concentrations are determined in the end-of-session blood sample taken with the blood pump speed reduced to 50 mL/min for two minutes (U(pwt2')). The aim of this study was to determine whether the V values determined by means of SPVV-UKM, ID, and U(pwt2') (V(ID)) are similar to those determined by the "gold standard" DDQ method (V(DDQ)). Eighty-two anuric hemodialysis patients were studied. RESULTS: V(DDQ) was 26.3 +/- 5.2 L; V(ID) was 26.5 +/- 4.8 L. The (V(ID)-V(DDQ)) difference was 0.2 +/- 1.6 L, which is not statistically significant (P= 0.242). Anthropometric volume (V(A)) calculated using Watson equations was 33.6 +/- 6.0 L. The (V(A)-V(DDQ)) difference was 7.3 +/- 3.3 L, which is statistically significant (P < 0.001). CONCLUSION: Anthropometric-based V values overestimate urea distribution volume calculated by DDQ and SPVV-UKM. ID allows adequate V values to be determined, and circumvents the problem of delayed postdialysis blood samples.