Florence Sens

Accuracy of GFR Estimation in Obese Patients

BACKGROUND AND OBJECTIVES Adequate estimation of renal function in obese patients is essential for the classification of patients in CKD category as well as the dose adjustment of drugs. However, the body size descriptor for GFR indexation is still debatable, and formulas are not validated in patients with extreme variations of weight. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This study included 209 stages 1-5 CKD obese patients referred to the Department of Renal Function Study at the University Hospital in Lyon between 2010 and 2013 because of suspected renal dysfunction. GFR was estimated with the Chronic Kidney Disease and Epidemiology equation (CKD-EPI) and measured with a gold standard method (inulin or iohexol) not indexed (mGFR) or indexed to body surface area determined by the Dubois and Dubois formula with either real (mGFRr) or ideal (mGFRi) body weight. Mean bias (eGFR-mGFR), precision, and accuracy of mGFR were compared with the results obtained for nonobese participants (body mass index between 18.5 and 24.9) who had a GFR measurement during the same period of time. RESULTS Mean mGFRr (51.6 ± 24.2 ml/min per 1.73 m(2)) was significantly lower than mGFR, mGFRi, and eGFRCKD-EPI. eGFRCKD-EPI had less bias with mGFR (0.29; -1.7 to 2.3) and mGFRi (-1.62; -3.1 to 0.45) compared with mGFRr (8.7; 7 to 10). This result was confirmed with better accuracy for the whole cohort (78% for mGFR, 84% for mGFRi, and 72% for mGFRr) and participants with CKD stages 3-5. Moreover, the Bland Altman plot showed better agreement between mGFR and eGFRCKD-EPI. The bias between eGFRCKD-EPI and mGFRr was greater in obese than nonobese participants (8.7 versus 0.58, P<0.001). CONCLUSIONS This study shows that, in obese CKD patients, the performance of eGFRCKD-EPI is good for GFR ≤ 60 ml/min per 1.73 m(2). Indexation of mGFR with body surface area using ideal body weight gives less bias than mGFR scaled with body surface area using real body weight.

Effectiveness of IHD with Adsorptive PMMA Membrane in Myeloma Cast Nephropathy: A Cohort Study

Background: In patients with cast nephropathy and acute kidney injury (AKI) requiring dialysis, the reduction of serum free light chains (FLC) using chemotherapy and intensive hemodialysis (IHD) with a high cut-off filter may improve renal and patient outcomes. We evaluated the effectiveness of a combination of chemotherapy and IHD with an adsorbent polymethylmethacrylate membrane (IHD-PMMA) on renal recovery and survival. Methods: A single-center retrospective cohort-study was conducted. Between 2007 and 2014, patients with dialysis-dependent acute cast nephropathy treated with chemotherapy and IHD-PMMA were included. Patients had six 6-h hemodialysis sessions a week, until predialysis serum FLC fell below 200 mg/L, for a maximum of 3 weeks. Primary outcomes were renal recovery, defined as dialysis independence, and survival. Results: Seventeen patients were included, all with stage 3 AKI. All received chemotherapy, mostly based on bortezomib and steroids (88%). Twelve patients (71%) achieved renal recovery, usually within 60 days (92%). At 3 months, the overall hematological response rate was 57%; hematological response was maintained for at least 2 years in 86% of responders. At 6, 12, and 24 months, 76, 75, and 62% of patients were alive, respectively. Higher reduction in involved FLC by day 12 (p = 0.022) and day 21 (p = 0.003) was associated with renal recovery. Patients with FLC reduction rate >50% by day 21 experienced a lower mortality (hazard ratio 0.10, 95% CI 0.02–0.63). Conclusion: In patients with dialysis-dependent myeloma cast nephropathy, early FLC removal by IHD-PMMA combined with chemotherapy was associated with high rates of renal recovery and survival.

Presence of Kidney Disease as an Outcome Predictor in Patients with Pulmonary Arterial Hypertension

Background: Pulmonary arterial hypertension (PAH) may lead to right heart failure and subsequently alter glomerular filtration rates (GFR). Chronic kidney disease (CKD, GFR <60 mL/min/1.73 m2) may also adversely affect PAH prognosis. This study aimed to assess how right heart hemodynamics was associated with reduced estimated GFR (eGFR) and the association of CKD with survival in PAH patients. Methods: In a prospective PAH cohort (2003–2012), invasive hemodynamics and eGFR were collected at diagnosis (179 patients) and during follow-up (159 patients). The prevalence of CKD was assessed at PAH diagnosis. Variables, including hemodynamics, associated with reduced eGFR at diagnosis and during follow-up were tested in multivariate analysis. The association of CKD with survival was evaluated using a multivariate Cox regression model. Results: At diagnosis, mean age was 60.4 ± 16.5 years, mean pulmonary arterial pressure was 43 ± 12 mm Hg, and eGFR was 74.4 ± 26.4 mL/min/1.73 m2. CKD was observed in 52 incident patients (29%). Independent determinants of reduced eGFR at diagnosis were age, systemic hypertension, and decreased cardiac index. Independent determinants of reduced eGFR during follow-up were age, female gender, PAH etiology, systemic hypertension, decreased cardiac index, and increased right atrial pressure. Age ≥60 years, female gender, NYHA 4, and CKD at diagnosis were independently associated with decreased survival. The adjusted hazards ratio for death associated with CKD was 1.81 (95% confidence interval [1.01–3.25]). Conclusion: CKD is frequent at PAH diagnosis and is independently associated with increased mortality. Right heart failure may induce renal hypoperfusion and congestion, and is associated with eGFR decrease.

Efficacy of extracorporeal albumin dialysis for acute kidney injury due to cholestatic jaundice nephrotoxicity.

We report a case of a 37-year-old man with Maturity Onset Diabetes of the Youth (MODY) type 5, admitted for an episode of cholestasis and a simultaneous acute kidney injury (AKI). Chronic liver disease was due to a mutation in the transcription factor 2 (TCF2) gene, thus highlighting the need for a close liver follow-up in these patients. AKI was attributed to a cholemic nephropathy based on the following rationale: (1) alternative diagnoses were actively ruled out; (2) the onset of AKI coincided with the onset of severe hyperbilirubinaemia; (3) renal pathology showed large bile tubular casts and a marked tubular necrosis and (4) creatinine serum dramatically decreased when bilirubin levels improved after the first sessions of extracorporeal albumin dialysis (ECAD), thus suggesting its role in renal recovery. Even though cholestasis can precipitate renal injury, the diagnosis of cholemic nephropathy could require a renal biopsy at times. Future studies should confirm the benefits of ECAD in cholemic nephropathy.