Fractional excretion of phosphorus and vascular calcification in stage 3 chronic kidney disease.

The role of renal excretion of Pi in relation to vascular calcification (VC) in patients in the early stages of chronic kidney disease (CKD) is controversial. Thus, we determine the relation between fractional excretion of phosphorus (FEP) and VC, measured using two methods in a cross-sectional study of patients with stage 3 CKD. We recorded demographic data, anthropometry, comorbidities and active treatment. We measured 24-hour urine FEP and, in serum, measured fibroblast growth factor 23 (FGF23), α-Klotho, intact parathyroid hormone (iPTH), calcium and phosphorus. VC was measured by lateral abdominal radiography (Kauppila index (KI)) and CT of the abdominal aorta (measured in Agatston units). In 57% of subjects, abnormal VC was present when measured using CT, and in only 17% using lateral abdominal radiography. Factors associated with VC using CT were age, cardiovascular risk factors, vascular comorbidity, microalbuminuria and levels of FGF23, phosphorus and calcium x phosphorus product (CaxP); although only age (OR 1.25, 95% CI 1.11 to 1.41), smoking (OR 21.2, CI 4.4 to 100) and CaxP (OR 1.21, CI 1.06 to 1.37) maintained the association in a multivariate analysis. By contrast, only age (OR 1.35, 95% CI 1.07 to 1.74), CaxP (OR 1.14, CI 1.13 to 1.92) and FEP (OR 1.07,95% CI 1004 to 1.14) were associated with abnormal VC in the lateral abdominal radiography. In conclusion, in patients with stage 3 CKD, the detection of VC by abdominal CT is more sensitive than conventional X-rays. Moreover, CaxP is associated with cardiovascular risk factors and vascular comorbidity; quantification of FEPi in these patients provides additional clinical information in advanced VC detected by KI.

Mycophenolate in refractory and relapsing lupus nephritis.

BACKGROUND: Mycophenolate (MF) is effective as induction and maintenance treatment in patients with lupus nephritis (LN). This study evaluates the efficacy and safety of MF in patients with refractory and relapsing LN. METHODS: Data were retrospectively obtained for 85 patients (35 refractory and 50 relapsing) from 11 nephrology departments in Spain. The primary endpoints were the incidence and cumulative number of renal responses and relapses and their relationship with baseline clinical and analytical data. The secondary endpoint was the appearance of side effects. RESULTS: The main clinical and analytical variables were similar both in refractory and relapsing LN. Most of the patients had received cyclophosphamide, and all of them switched to MF. 74 patients (87%) achieved a response (69% partial, 31% complete). Age at starting MF, gender, pathological classification, body mass index, blood pressure, baseline renal function, and proteinuria were not associated with achieving response. After stopping MF, 3 of 19 patients (15.7%) relapsed, all at 6 months of follow-up. No differences were found between clinical and analytical variables and number of relapses. Side effects were unremarkable, except for 1 patient, who died of thrombocytopenia and ovarian hemorrhage. CONCLUSIONS: Switching to MF from other immunosuppressive treatments is effective and safe in refractory and relapsing LN.