Pruritus in Hemodialysis Patients: Longitudinal Associations With Clinical and Patient-Reported Outcomes

RATIONALE & OBJECTIVE

Cross-sectional studies have reported an association of chronic kidney disease-associated pruritus (CKD-aP) with adverse clinical events and patient-reported outcomes (PROs). We studied the longitudinal associations between changes in CKD-aP and clinical outcomes among patients receiving maintenance hemodialysis.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

7,976 hemodialysis recipients across 21 countries in phases 4-6 (2009-2018) of the Dialysis Outcomes and Practice Patterns Study (DOPPS) who had 2 CKD-aP assessments approximately 12 months apart.

EXPOSURES

Exposure status was based on the assessment of pruritis initially and again approximately 1 year later. Four groups were identified, including those with moderate or more severe pruritis only at the initial assessment (resolved), only at the second assessment (incident), at neither assessment (absent), or at both assessments (persistent).

OUTCOMES

Laboratory values and PROs ascertained at the initial assessment of pruritis and 1 year later.

ANALYTICAL APPROACH

Linear mixed model to investigate changes in laboratory values and PROs over the 1-year study period across the 4 exposure groups.

RESULTS

51% of patients had moderate to severe CKD-aP symptoms at either assessment (22% at both). The prevalences of depression, restless sleep, and feeling drained increased over the study period (+13%,+10%, and+14%, respectively) among patients with incident pruritus and decreased (-5%, -8%, and -12%, respectively) among patients with resolved pruritus. Minimal changes in PROs over time were observed for the absent and persistent groups. Changes over time in laboratory values (phosphorus, Kt/V) were not detected for either of these groups. Compared with patients with absent CKD-aP, the adjusted HRs for patients with persistent CKD-aP were 1.29 (95% CI, 1.09-1.53) for all-cause mortality, 1.17 (1.07-1.28) for all-cause hospitalization, and 1.48 (1.26-1.74) for cardiovascular events.

LIMITATIONS

No interim evaluation of CKD-aP symptoms between the 2 assessments; potential selection bias from patients who died or were otherwise lost to follow-up before the second assessment.

CONCLUSIONS

CKD-aP symptoms are chronic, and these findings highlight the potential value of repeated assessment of this symptom using standardized approaches. Future research should systematically investigate potential causes of CKD-aP and options for its effective treatment.

PLAIN-LANGUAGE SUMMARY

Previous research has studied itching and its consequences in hemodialysis recipients only at a single time point. We surveyed 7,976 patients receiving maintenance hemodialysis to assess itching over a period of 1 year. We found that, among those experiencing itching at the initial assessment, more than half had persistent symptoms 1 year later. Those in whom itching developed during follow-up were more likely to experience depression, poor sleep, long recovery times after dialysis, and feeling faint or drained. These patients also rated their quality of life as poorer than those who did not experience itching. These findings emphasize the potential value of clinical detection of itching and the pursuit of effective treatments for patients receiving dialysis experiencing these symptoms.

Heat Shock Protein 70 Is Involved in the Efficiency of Preconditioning with Cyclosporine A in Renal Ischemia Reperfusion Injury by Modulating Mitochondrial Functions

Cyclosporine A (CsA) preconditioning is known to target mitochondrial permeability transition pore and protect renal function after ischemia reperfusion (IR). The upregulation of heat-shock protein 70 (Hsp70) expression after CsA injection is thought to be associated with renal protection. The aim of this study was to test the effect of Hsp70 expression on kidney and mitochondria functions after IR. Mice underwent a right unilateral nephrectomy and 30 min of left renal artery clamping, performed after CsA injection and/or administration of the Hsp70 inhibitor. Histological score, plasma creatinine, mitochondrial calcium retention capacity, and oxidative phosphorylation were assessed after 24 h of reperfusion. In parallel, we used a model of hypoxia reoxygenation on HK2 cells to modulate Hsp70 expression using an SiRNA or a plasmid. We assessed cell death after 18 h of hypoxia and 4 h of reoxygenation. CsA significantly improved renal function, histological score, and mitochondrial functions compared to the ischemic group but the inhibition of Hsp70 repealed the protection afforded by CsA injection. In vitro, Hsp70 inhibition by SiRNA increased cell death. Conversely, Hsp70 overexpression protected cells from the hypoxic condition, as well as the CsA injection. We did not find a synergic association between Hsp70 expression and CsA use. We demonstrated Hsp70 could modulate mitochondrial functions to protect kidneys from IR. This pathway may be targeted by drugs to provide new therapeutics to improve renal function after IR.

Oxalate: from physiology to pathology

Hyperoxaluria is defined by an increase of urinary oxalate, leading to kidney stones, nephrocalcinosis and/or chronic kidney disease. There are different diseases related to hyperoxaluria: (1) kidney stones, 50% of them being explained by intermittent hyperoxaluria, secondary to dietary mistakes such as low hydration, excess of oxalate consumption and/or low calcium consumption; (2) primary hyperoxaluria, a genetic orphan disease inducing a massive production of oxalate by the liver, leading to increased plasma oxalate increase and saturation, and further systemic oxalosis with oxalate deposition, nephrocalcinosis and ultimately kidney failure, the management of this disease being currently dramatically modified by the onset of new therapeutic tools such as RNA interference; and (3) enteric hyperoxaluria, resulting from increased intestinal oxalate absorption because of intestinal malabsorption (short bowel syndrome, bariatric surgery, exocrine pancreatic insufficiency, etc.). Diagnosis and therapeutic management of these diseases require a full understanding of oxalate physiology that we detail in this review.

Sulforaphane exhibits potent renoprotective effects in preclinical models of kidney diseases: A systematic review and meta-analysis

AIMS

Sulforaphane (SFN), a naturally occurring isothiocyanate found in cruciferous vegetables, has received extensive attention as a natural activator of the Nrf2/Keap1 cytoprotective pathway. In this review, a meta-analysis and systematic review of the renoprotective effects of SFN were performed in various preclinical models of kidney diseases.

MAIN METHODS

The primary outcome was the impact of SFN on renal function biomarkers (uremia, creatininemia, proteinuria or creatinine clearance) and secondary outcomes were kidney lesion histological indices/kidney injury molecular biomarkers. The effects of SFN were evaluated according to the standardized mean differences (SMDs). A random-effects model was applied to estimate the overall summary effect.

KEY FINDINGS

Twenty-five articles (out of 209 studies) were selected from the literature. SFN administration significantly increased creatinine clearance (SMD +1.88 95 % CI: [1.09; 2.68], P < 0.0001, I² = 0 %) and decreased the plasma creatinine (SMD -1.24, [-1.59; -0.88], P < 0.0001, I² = 36.0 %) and urea (SMD -3.22 [-4.42, -2.01], P < 0.0001, I² = 72.4 %) levels. SFN administration (median dose: 2.5 mg/kg, median duration: 3 weeks) significantly decreased urinary protein excretion (SMD -2.20 [-2.68; -1.73], P < 0.0001, I² = 34.1 %). It further improved two kidney lesion histological indices namely kidney fibrosis (SMD -3.08 [-4.53; -1.63], P < 0.0001, I² = 73.7 %) and glomerulosclerosis (SMD -2.24 [-2.96; -1.53], P < 0.0001, I² = 9.7 %) and decreased kidney injury molecular biomarkers (SMD -1.51 [-2.00; -1.02], P < 0.0001, I² = 0 %).

SIGNIFICANCE

These findings provide new insights concerning preclinical strategies for treating kidney disease or kidney failure with SFN supplements and should stimulate interest in clinical evaluations of SFN in patients with kidney disease.

Lumasiran for Advanced Primary Hyperoxaluria Type 1: Phase 3 ILLUMINATE-C Trial

RATIONALE & OBJECTIVE

Lumasiran reduces urinary and plasma oxalate (POx) in patients with primary hyperoxaluria type 1 (PH1) and relatively preserved kidney function. ILLUMINATE-C evaluates the efficacy, safety, pharmacokinetics, and pharmacodynamics of lumasiran in patients with PH1 and advanced kidney disease.

STUDY DESIGN

Phase 3, open-label, single-arm trial.

SETTING & PARTICIPANTS

Multinational study; enrolled patients with PH1 of all ages, estimated glomerular filtration rate ≤45 mL/min/1.73 m² (if age ≥12 months) or increased serum creatinine level (if age <12 months), and POx ≥20 μmol/L at screening, including patients with or without systemic oxalosis.

INTERVENTION

Lumasiran administered subcutaneously; 3 monthly doses followed by monthly or quarterly weight-based dosing.

OUTCOME

Primary end point: percent change in POx from baseline to month 6 (cohort A; not receiving hemodialysis at enrollment) and percent change in predialysis POx from baseline to month 6 (cohort B; receiving hemodialysis at enrollment). Pharmacodynamic secondary end points: percent change in POx area under the curve between dialysis sessions (cohort B only); absolute change in POx; percent and absolute change in spot urinary oxalate-creatinine ratio; and 24-hour urinary oxalate adjusted for body surface area.

RESULTS

All patients (N = 21; 43% female; 76% White) completed the 6-month primary analysis period. Median age at consent was 8 (range, 0-59) years. For the primary end point, least-squares mean reductions in POx were 33.3% (95% CI, -15.2% to 81.8%) in cohort A (n = 6) and 42.4% (95% CI, 34.2%-50.7%) in cohort B (n = 15). Improvements were also observed in all pharmacodynamic secondary end points. Most adverse events were mild or moderate. No patient discontinued treatment or withdrew from the study. The most commonly reported lumasiran-related adverse events were injection-site reactions, all of which were mild and transient.

LIMITATIONS

Single-arm study without placebo control.

CONCLUSIONS

Lumasiran resulted in substantial reductions in POx with acceptable safety in patients with PH1 who have advanced kidney disease, supporting its efficacy and safety in this patient population.

FUNDING

Alnylam Pharmaceuticals.

TRIAL REGISTRATION

Registered at ClinicalTrials.gov with study number NCT04152200 and at EudraCT with study number 2019-001346-17.

PLAIN-LANGUAGE SUMMARY

Primary hyperoxaluria type 1 (PH1) is a rare genetic disease characterized by excessive hepatic oxalate production that frequently causes kidney failure. Lumasiran is an RNA interference therapeutic that is administered subcutaneously for the treatment of PH1. Lumasiran has been shown to reduce oxalate levels in the urine and plasma of patients with PH1 who have relatively preserved kidney function. In the ILLUMINATE-C study, the efficacy and safety of lumasiran were evaluated in patients with PH1 and advanced kidney disease, including a cohort of patients undergoing hemodialysis. During the 6-month primary analysis period, lumasiran resulted in substantial reductions in plasma oxalate with acceptable safety in patients with PH1 complicated by advanced kidney disease.

Mild Therapeutic Hypothermia Protects from Acute and Chronic Renal Ischemia-Reperfusion Injury in Mice by Mitigated Mitochondrial Dysfunction and Modulation of Local and Systemic Inflammation

Renal ischemia-reperfusion (IR) injury can lead to acute kidney injury, increasing the risk of developing chronic kidney disease. We hypothesized that mild therapeutic hypothermia (mTH), 34 °C, applied during ischemia could protect the function and structure of kidneys against IR injuries in mice. In vivo bilateral renal IR led to an increase in plasma urea and acute tubular necrosis at 24 h prevented by mTH. One month after unilateral IR, kidney atrophy and fibrosis were reduced by mTH. Evaluation of mitochondrial function showed that mTH protected against IR-mediated mitochondrial dysfunction at 24 h, by preserving CRC and OX-PHOS. mTH completely abrogated the IR increase of plasmatic IL-6 and IL-10 at 24 h. Acute tissue inflammation was decreased by mTH (IL-6 and IL1-β) in as little as 2 h. Concomitantly, mTH increased TNF-α expression at 24 h. One month after IR, mTH increased TNF-α mRNA expression, and it decreased TGF-β mRNA expression. We showed that mTH alleviates renal dysfunction and damage through a preservation of mitochondrial function and a modulated systemic and local inflammatory response at the acute phase (2–24 h). The protective effect of mTH is maintained in the long term (1 month), as it diminished renal atrophy and fibrosis, and mitigated chronic renal inflammation.

MO863: Electronic Patient Reported Outcome (EPRO) Collection in Dopps: Prospective Study Designed to Understand the Severity and Temporal Changes in Pruritus Symptoms in Hemodialysis Patients

BACKGROUND AND AIMS

Chronic kidney disease-associated pruritus (CKD-aP) is often seen to affect 30–40% of hemodialysis (HD) patients, and baseline CKD-aP symptoms have been associated with worse quality of life, poor sleep quality, depression and survival. A need exists for documenting CKD-aP severity longitudinally via several CKD-aP instruments to allow for temporal evaluation of different domains of CKD-aP burden, and their relationships to other patient-reported outcomes (PROs). This will help to further inform the extent to which different domains of well-being are impacted by CKD-aP over time, and its variability across patients, for tailoring individualized clinical care of HD patients afflicted by CKD-aP. The Dialysis Outcomes and Practice Patterns Study (DOPPS) is an international prospective cohort of adult in-centre HD patients, with patients randomly selected from representative national samples of HD facilities. Many prior studies by DOPPS and others have used only a baseline measure of CKD-aP, which may underestimate the strength of the true associations with clinical outcomes. With more frequent data collection to update exposures and understand trajectories, we can better evaluate the extent to which CKD-aP is episodic versus chronic. We can also assess whether patients with more consistently severe CKD-aP have worse PROs than patients who are currently—but only recently—bothered by CKD-aP. These gaps in knowledge present an opportunity to undertake a prospective study to link longitudinal clinical data with focused and frequent capture of CKD-aP and PROs to better understand the prevalence, burden and management of CKD-aP from HD patients’ perspectives.

METHOD

This prospective electronic PRO (ePRO) study involves &gt;100 HD units from the 7 European countries participating in DOPPS 7 (Belgium, France, Germany, Italy, Spain, Sweden, UK). The ePRO will be distributed at HD facilities at 3-month intervals during an 18-month data collection period from 2021–3. The ePRO will be offered to all patients enrolled in the DOPPS, yielding a potential sample of 2000–500 patients based on expected participation and return rates (∼67%). The ePRO data collection is focused on use of mobile (tablet, phone) devices used frequently by patients, but will also be operational on a desktop or laptop computer. Patients will use their personal device to scan a unique QR code, and typically complete the questionnaire while on site at their HD facility. The ePRO will include a combination of validated CKD-aP scales, general quality of life related instruments and healthcare resource utilization (HCRU), i.e. patient reported capture of itch medications and specialist visits known to the patient but not typically in the dialysis chart. A complete list of the ePRO components is shown in Table 1. These ePRO data, together with linked longitudinal clinical data captured in DOPPS, will serve as the analytical basis for several planned research projects, including (i) comparing approaches to measure CKD-aP burden; (ii) describing within-patient trajectories of CKD-aP burden and associations with PROs; and (iii) CKD-aP and short-term outcomes including HCRU, hospitalization and mortality in the 3-months following each CKD-aP assessment.

RESULTS

Data collection is underway as of August 2021, with initial data expected in early 2022. While not yet available, we expect to present preliminary descriptive data at the ERA-EDTA in May 2022.

CONCLUSION

The community lacks longer-term, frequently captured data on pruritus severity and management in the HD setting. This DOPPS 18-month prospective ePRO will help address novel research questions investigating the longitudinal burden of pruritus from the patient perspective, using multiple validated instruments and relationships to PROs, clinical outcomes and healthcare resource utilization.

MO464: Long-Term Renal Outcomes After ST-Elevation Myocardial Infarction Treated by Percutaneaous Coronary Intervention

BACKGROUND AND AIMS

Among patients with ST-elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI), short- and long-term renal function evaluations are of prime importance. Most studies have focused on short-term renal dysfunction and acute kidney injury (AKI) occurrence after STEMI treated by PCI, which is associated with major adverse cardiovascular events (MACE) and especially the occurrence of heart failure. However, few studies have focused on long-term renal outcomes.

We aimed to describe renal function evolution and to determine predictors of estimated glomerular filtration rate (eGFR) decline one year after STEMI is treated by PCI.

METHOD

From May 2016 to July 2020, 322 consecutive patients with STEMI who underwent PCI revascularization were enrolled prospectively.

Serum creatinine (SCr) concentration was routinely measured at patient admission, after 48 h or hospital discharge, then during systematic 1-month and 1-year clinical check-ups, AKI was determined according to the Acute Kidney Injury Network (AKIN) definition. The estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD EPI) formula. The evolution of renal function was evaluated by the difference between admission and 1-month or 1-year eGFR. Rapid progression was defined as a decline in eGFR of more than 5 mL/min/1.73m² per year. Determinants of eGFR decline ≥ 10 mL/min/1.73m² per year were analyzed with multivariate logistic regressions.

RESULTS

The mean age was 59.6 years, 29.5% of patients had a medical history of hypertension, 13.8% had diabetes and 52.8% presented with anterior myocardial infarction. Median admission SCr concentration was 71 µmol/L, with an eGFR of 96.5 mL/min/1.73m² [inter quartile range (IQR): 84.4–105.1]. A total of 38 patients (11.8%) developed AKI.

In the whole population median eGFR decline was 7.7 mL/min/1.73 m² (1.2–14.4) and 8 mL/min/1.73 m² [1.3–15.9] 1-month and 1-year after STEMI respectively (Figure 1). Rapid eGFR decline was found in 59.7% of the total population and 44.6% of patients presented a 1-year eGFR decline of at least 10 mL/min/1.73 m². AKI patients had significant lower eGFR at 1-month and 1-year follow up (median 1-year eGFR of 74.5 mL/min/1.73m² (52.4–96.4) versus 88.1 mL/min/1.73m² (74.0–100.3) in non-AKI patients, P = 0.01). There was no significant difference between AKI and non-AKI patients regarding rates of eGFR decline at both 1-month and 1-year after inclusion.

Multivariate analysis (Table 1) showed that age and 1-month eGFR decline was significantly associated with 1-year eGFR decline ≥ 10 mL/min/1.73m². Especially, 1-month eGFR decline greater than 10 mL/min/1.73m² was an independent and stratified predictor of 1-year eGFR decline with an odds ratio (OR) of 7.45 [95% confidence interval (CI): 2.76–22.81, P &lt; 0.01). AKI occurrence and peak hs-I troponin were not found as predictors of 1-year eGFR decline.

CONCLUSION

Among STEMI patients treated by PCI, a large majority of patients present a significant decline in renal function 1-year after STEMI, regardless of AKI occurrence or infarct size. One-month eGFR decline is a strong predictor of 1-year eGFR evolution and could help identify high-risk patients and adjust nephrological care. Our findings bear important clinical implications and underline the need for longitudinal follow-up of renal function after STEMI is treated by PCI.

MO660: Medium Chain Fatty Acids used as Binding Competitors of Albumin Improve the Dialytic Clearance of Protein-Bound Uraemic Toxins

BACKGROUND AND AIMS

Protein-bound uraemic toxins (PBUTs) remain a concerning burden in patients with end-stage renal disease (ESRD) since their removal in haemodialysis (HD) is limited by their strong binding to plasma proteins. By increasing their circulating free fraction during HD, "binding competitors" of albumin could be used to increase their dialytic clearance. Medium-chain fatty acids (MCFAs, 4–10 carbon length) are potent candidates for that purpose. The aim of this work was to evaluate the displacing capacities of MCFAs.

METHOD

Sodium salts of butanoic acid (C4), hexanoic acid (C6), octanoic acid (C8) and decanoic acid (C10) were purchased from Sigma-Aldrich. The interaction between MCFAs and serum albumin was explored using two fluorescent probes: warfarin (specific to Sudlow's site I) and dansylsarcosine (specific to Sudlow's site II). Indoxyl-sulfate (IS, final concentration 212 µM) and p-cresyl sulfate (p-CS, final concentration 250 µM) were added to a 600 µM bovine serum albumin-phosphate buffered saline solution. The free fractions of IS and p-CS were assayed with or without MCFAs (1–2 mM) using ultrafiltration devices. To mimic the removal of PBUTs during an HD session, batches of 2L of fresh bovine blood were loaded with IS and p-CS (final concentration 200 µM). A 2-h closed-loop HD session was performed using a Fresenius 5008 CorDiax HD generator (Fresenius, Germany). A solution of 224 mM of sodium octanoate (C8) was perfused using the electric syringe pump at the rate of 150 µL/min; a solution of saline 0.9% was used as a control. A total of 1 mL of blood was sampled every 15 min through the arterial sampling port and concentrations of IS and pCS were assayed by HPLC coupled with fluorescence detection. The haemolytic effect of MCFAs was evaluated in vitro by assaying the free haemoglobin concentration.

RESULTS

Among the short-chain fatty acids tested, octanoic (C8) and decanoic (C10), acids were more prone to displace dansylsarcosine from Sudlow's site II of albumin (which is the main binding site of IS and p-CS). In vitro, the incubation with 2 mM of sodium octanoate or decanoate increased the free fraction of PBUTs from 12 to 53% for p-CS (4.4 folds change, P &lt; .05) and from 11 to 45% for IS (4.1 folds change, P &lt; .05). The per-dialytic infusion of sodium octanoate significantly increased the fractional removal of p-CS (from 38 to 88%, P &lt; .001) and IS (from 36 to 91%, P &lt; .001) (Figure 1). No significant haemolysis was observed for the concentration of MCFAs ˂ 2 mmol/L.

CONCLUSION

MCFAs and especially C8 and C10 are serious candidates to displace the binding of PBUTs such as p-CS and IS. The per-dialytic administration of MCFA significantly increased the removal of PBUTs and could constitute a new strategy to get rid of these compounds and prevent their accumulation in end-stage kidney disease patients. Due to their safeness (toxicity and metabolism profiles in vivo), MCFAs could be better tolerated than other chemical compounds that have already been tested clinically such as ibuprofen. Further in vivo studies are, however needed to carefully evaluate this potentially new therapeutic option.

MO901: Longitudinal Pruritus Assessment in Hemodialysis Patients: 1-Year Course of Symptoms and Associations With Clinical and Patient-Reported Outcomes

BACKGROUND AND AIMS

The burden of chronic kidney disease-associated pruritus (CKD-aP) in hemodialysis (HD) patients, and its association with adverse clinical events and patient-reported outcomes (PROs) has been well-established. However, most studies focus on a single baseline CKD-aP assessment. In this study, we quantify the extent to which pruritus symptoms vary &gt;1 year, and relationship with associated clinical and patient-reported outcomes.

METHOD

We included 7976 HD patients across 21 countries in the Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 4–6 (2009–18) who had 2 CKD-aP assessments 12 months (±6 months) apart, with concurrent PRO collection. CKD-aP intensity was assessed by a single question in the KDQOL-36 asking about the extent patients were bothered by itch over the past 4 weeks. We categorized patients into 4 groups—those at least moderately (versus somewhat or not at all) bothered by itchy skin in Year 1 only (Yes/No), Year 2 only (No/Yes), neither (No/No), or both (Yes/Yes) time points. Difference-in-difference analyses were used to estimate changes in laboratory values and PROs between Years 1 and 2, by within-patient changes in CKD-aP severity. Cox regression was used to estimate rates of mortality and hospitalization, with follow-up starting after the Year 2 CKD-aP assessment, across the 4 exposure groups, adjusted for confounders.

RESULTS

Half of the patients were at least moderately bothered by pruritus over the course of 1 year: 22% of patients were at least moderately bothered by CKD-aP at each annual assessment (Yes/Yes); 14% each were bothered at Year 1 only (Yes/No) or Year 2 only (No/Yes); 49% were not bothered at either CKD-aP assessment (No/No). These proportions were similar across DOPPS regions. Changes in laboratory values—including calcium, phosphorus, parathyroid hormone (PTH), albumin, hemoglobin, single pool Kt/V—between Years 1 and 2 varied minimally by within-patient changes in CKD-aP. Changes in some targeted PROs (depression, sleep quality, feeling faint or drained) tracked closely with changes in CKD-aP: the proportion of patients reporting &gt; = 3 nights/week of restless sleep increased from 38% to 48% in the No/Yes group, decreased from 48% to 40% in the Yes/No group, and was unchanged between Years 1 and 2 in the No/No and Yes/Yes groups (Table 1). Changes in more general PROs (physical [PCS] and mental [MCS] component summary scores) were modest, and only varied by 2–3 points across the 4 CKD-aP exposure groups. The all-cause mortality HR (95% confidence interval), compared with the No/No reference group, was 1.22 (0.99–1.51) for Yes/No, 1.32 (1.07–1.63) for No/Yes and 1.31 (1.11–1.56) for Yes/Yes. Results for hospitalization and other clinical outcomes are shown in Figure 1.

CONCLUSION

Our findings indicate that half of chronic HD patients were at least moderately bothered by CKD-aP at some point over the course of 1 year, reflecting an unmet medical need, and that CKD-aP symptoms remained unresolved 12 months later for the majority of HD patients who were bothered by itchy skin at baseline, highlighting the chronic nature of the condition. The trend towards worse patient-reported outcomes for those affected in Year 2 but not Year 1 implicates the consequences of patients’ significant adjustment to this new, often unrelenting, symptom. Those with chronic pruritus had higher rates of hospitalization and cardiovascular events, underscoring the impact of patients with chronic pruritus on hospital systems. Moreover, those affected by pruritus at any point in the year had higher rates of mortality, further highlighting the importance of diagnosing pruritus and investigating its effect on cardiovascular events. Future research should investigate potential causes of CKD-aP symptoms more systematically and focus on how potential treatments can aide in patients’ relief.

MO456: Renal and Major Clinical Outcomes After Nephrectomy in Patients With Pre-Existing Chronic Kidney Disease (ON-CKD Study)

BACKGROUND AND AIMS

Partial nephrectomy (PN) has progressively replaced radical nephrectomy (RN) whenever feasible for renal tumors. However, its effects on renal outcomes are less known in patients with pre-existing chronic kidney disease (CKD) or with solitary kidney (SK). We aimed to assess renal and major clinical outcomes after PN or RN in patients with moderate to severe CKD or SK.

METHOD

We included all surgical procedures conducted between 2013 and 2018 in the Hospices Civils de Lyon, in patients with last pre-operative estimated glomerular filtration rate (eGFR) &lt;60mL/min/1.73m², or with SK. Exclusion criteria were eGFR &lt; 15mL/min/1.73m² or dialysis, RN on SK, ablative therapy. Demographic, tumors and surgeries characteristics were collected, as well as eGFR 1 month and 1 year after surgery. Main outcome was a composite criterion including CKD progression or major cardio-vascular events or death, assessed 1 year after surgery. Predictors of the main outcome were determined using multivariate analyses.

RESULTS

We included 173 procedures (67 RN and 79 PN on CKD patients, 27 PN on SK patients). Patients undergoing RN were older, had bigger tumors and higher T stages on TNM classification. Preoperative estimated glomerular filtration rate (eGFR) and CKD stages were not different between the groups. One year after surgery, PN was associated with less occurrence of the main composite outcome compared to RN (42.9% versus 70.7%, P &lt; 0.01). On multivariate analysis, independent risk factors for the main outcome were postoperative AKI (no AKI as reference; AKI stage 1 odds ratio (OR) = 8.68, 95% confidence interval (CI) 3.23–23.33; AKI stage 2 OR = 23.50, 95% CI 2.33–236.51; AKI stage 3 OR = 28.87, 95% CI 4.77–167.61) and bigger tumor size (OR = 1.21/cm, 95% CI 1.02–1.45), while preoperative eGFR was not (Table 1). Compared to pre-operative values, eGFR significantly decreased both after RN or PN 1 month after surgery (eGFR loss -12mL/min 1.73m² after RN P &lt; 0.001, −3mL/min/1.73m² after PN, P &lt; 0.05) and this decrease remained stable 1 year after surgery (eGFR loss -11mL/min/1.73m² after RN, P &lt; 0.001, −3mL/min/1.73m² after PN, P &lt; 0.05), but renal function was better preserved after PN than after RN at 1 month (P &lt; 0.05) or 1 year (P &lt; 0.01) (Figure 1).

CONCLUSION

In moderate to severe CKD patients, PN was associated with less risk of CKD progression or major cardio-vascular event or death 1 year after surgery, compared to RN. Postoperative AKI was the major determinant of clinical and renal outcomes.

Assessing Global Kidney Nutrition Care

BACKGROUND AND OBJECTIVES

Nutrition intervention is an essential component of kidney disease management. This study aimed to understand current global availability and capacity of kidney nutrition care services, interdisciplinary communication, and availability of oral nutrition supplements.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The International Society of Renal Nutrition and Metabolism (ISRNM), working in partnership with the International Society of Nephrology (ISN) Global Kidney Health Atlas Committee, developed this Global Kidney Nutrition Care Atlas. An electronic survey was administered among key kidney care stakeholders through 182 ISN-affiliated countries between July and September 2018.

RESULTS

Overall, 160 of 182 countries (88%) responded, of which 155 countries (97%) answered the survey items related to kidney nutrition care. Only 48% of the 155 countries have dietitians/renal dietitians to provide this specialized service. Dietary counseling, provided by a person trained in nutrition, was generally not available in 65% of low-/lower middle-income countries and "never" available in 23% of low-income countries. Forty-one percent of the countries did not provide formal assessment of nutrition status for kidney nutrition care. The availability of oral nutrition supplements varied globally and, mostly, were not freely available in low-/lower middle-income countries for both inpatient and outpatient settings. Dietitians and nephrologists only communicated "sometimes" on kidney nutrition care in ≥60% of countries globally.

CONCLUSIONS

This survey reveals significant gaps in global kidney nutrition care service capacity, availability, cost coverage, and deficiencies in interdisciplinary communication on kidney nutrition care delivery, especially in lower-income countries.

MO336RENAL CONTRAST-ENHANCED ULTRASOUND (CEUS) TO EVALUATE EARLY AND CHRONIC MODIFICATIONS OF RENAL PERFUSION AND TO PREDICT RENAL DYSFUNCTION AFTER RENAL ISCHEMIA-REPERFUSION IN MICE

Background and Aims

Renal ischemia-reperfusion can lead to acute kidney injury (AKI), increasing the risk of developing chronic kidney disease (CKD) through inflammation and vascular lesions. Serum urea or creatinine level routinely used as diagnostic indices of renal function are always delayed from the onset of the disease. Therefore, we currently lack reliable markers to early detect AKI, especially in animals.

We aimed to show that non-invasive renal contrast-enhanced ultrasound (CEUS) could be a reliable tool to assess early and chronic changes of renal perfusion after renal ischemia-reperfusion.

Method

Male C57BL6 mice underwent 15 minutes of unilateral renal ischemia by clamping of the left renal vascular pedicle (n = 7), or a sham procedure (n = 3), under inhaled general anesthesia by Sevoflurane. A renal ultrasound was performed on the left ischemic kidney at baseline 1 week before the surgery, then, 20 minutes after reperfusion to assess early modifications of renal perfusion, and 1 month after reperfusion to follow chronic modifications. CEUS was performed in supine position by using a high-resolution ultrasonic imaging system (VEVO 3100 Fujifilm Visualsonics, Toronto, Canada) with a MX550D probe fixed in place with an iron support, ensuring the constant imaging plane throughout acquisition. First, a continuous infusion of microbubbles (VS-11913, Fujifilm Visualsonics, Toronto, Canada) was done through the tail vein, then a high mechanical index burst was given to destroy microbubbles when the contrast enhancement had reached a steady state, and finally, low mechanical-index imaging mode was used until, and 30 sec after the contrast agent concentration reached the plateau. Images were recorded and were analyzed using the “destruction-replenishment” fitting model of the Vevo LAB software (Fujifilm Visualsonics, Toronto, Canada). Renal perfusion was estimated by the total renal Blood Volume (rBV) parameter and was expressed as percentage of the baseline value for each animal. Renal function was also assessed by serum urea concentration 1 month after reperfusion, and the long axis lengths of both the kidneys were measured ex vivo after the mice were euthanized.

Results

Renal perfusion of the ischemic kidney measured by CEUS was significantly decreased as soon as 20 minutes of reperfusion compared to baseline (median 28,8% of baseline value; interquartiles [20,1 – 69,8%]). 1 month after reperfusion, renal perfusion recovered partially but was still significantly decreased compared to baseline (median 79,9% of baseline value; interquartiles [52,8 – 99,9%]) (Figure A). In sham operated mice, renal perfusion did not differ from baseline at 20 minutes or 1 month (p &gt; 0.05).

The renal function, assessed by serum urea, was mildly but significantly impaired 1 month after ischemia-reperfusion compared with sham (median serum urea 9,8 vs. 7,6 mmol/L) (p = 0.02), and this was consistent with the observed kidney atrophy in the ischemic group when compared to the contralateral kidney (median long axis length 7,5 vs 10,8 mm) (p = 0.03).

Moreover, the decrease of renal perfusion 20 minutes after reperfusion was significantly correlated with the impairment of renal perfusion 1 month after reperfusion (Pearson r = 0.836, p = 0.005) and with the serum urea level at 1 month (Pearson r = -0.710, p = 0.03) (Figure B-C).

Conclusion

Renal CEUS was able to detect early impairment of renal perfusion as soon as 20 minutes after 15 minutes of renal ischemia in mice, and perfusion was still decreased 1 month after reperfusion, compared to baseline. This early impairment of perfusion was correlated with the chronic decrease of renal perfusion and renal function 1 month after reperfusion. This was also associated with a significant kidney atrophy. CEUS is an interesting non-invasive tool to assess renal lesions dynamically after ischemia-reperfusion.

MO352RENAL DYSFUNCTION AS A MAJOR PREDICTOR OF CLINICAL OUTCOMES IN ANTERIOR STEMI PATIENTS

Background and Aims

Among ST-segment elevation myocardial infarction (STEMI) patients, the respective impact of the baseline renal function, of the development of acute kidney injury (AKI), and of their combination, on the long-term cardiovascular outcomes, remain unclear.

Method

The present study was based on a post hoc analysis of the CIRCUS trial database, a multicentre randomized study which gathered 969 patients with anterior STEMI treated by primary percutaneous intervention (PPCI) within 12 hours of symptoms onset. Uni and multivariate regressions were performed to identify if the estimated glomerular filtration rate (eGFR) at admission and the development of AKI were associated with (1) cardiovascular death and heart failure (HF) at one year and (2) sub-optimal treatment prescription at discharge.

Results

A total of 822 patients were included. The mean baseline eGFR was 86 ± 19 mL/min/1.73m2. AKI occurred in 97 patients (11.8%). Baseline eGFR &lt;60mL/min/1.73m2 was associated with HF (40.0 vs 16.8%, p&lt;0.001) and with a sub-optimal treatment at discharge (35.9 vs 18.9%, p=0.001). AKI was associated with cardiovascular death (12.4 vs 2.8%, p&lt;0.001), HF (50.5 vs 14.9%, p&lt;0.001), and sub-optimal treatment (35.8 vs 18.5%, p&lt;0.001). The multivariate analysis showed that AKI (OR=4.88, CI=2.89-8.27) and a lower baseline eGFR (OR=1.29 per 10mL/min/1.73m2 decrease, CI=1.11-1.50) are independent predictors of cardiovascular death or HF after anterior STEMI.

Conclusion

In anterior STEMI patients undergoing PPCI, the development of AKI was the strongest independent predictor of poor clinical outcome at one year. The study suggests the need for a tailored monitoring of STEMI patients with AKI or baseline kidney dysfunction.

Reconsidering adsorption in hemodialysis: is it just an epiphenomenon? A narrative review

Since the first attempt at extracorporeal renal replacement therapy, renal replacement therapy has been constantly improved. In the field of hemodialysis, substantial efforts have been made to improve toxin removal and biocompatibility. The advent of hemodiafiltration (HDF) and, more recently, of mid cut-off membranes have contributed to management of patients with end-stage renal disease (ESRD). Although several uremic toxins have been discovered, we know little about the clinical impact of their clearance in hemodialysis patients. In addition, a great deal of progress has been made in the areas of filtration and diffusion, but the adsorptive properties of hemodialysis membranes remain under-studied. The mechanism of action of adsorption is based on the attraction between the polymer of the dialysis membrane and the solutes, through hydrophobic interactions, ionic or electrostatic forces, hydrogen bonds or van der Waals forces. Adsorption on the dialysis membrane depends on the membrane surface, pore size, structure and electric load. Its involvement in toxin removal and biocompatibility is significant, and is not just an epiphenomenon. Diffusive and convective properties cannot be improved indefinitely and high permeability membranes, despite their high performance in the clearance of many toxins, have several limitations for long-term use in hemodialysis. This review will discuss why adsorption should be reconsidered and better characterized to improve efficiency and adequacy of dialysis.

The International Society of Renal Nutrition and Metabolism Commentary on the National Kidney Foundation and Academy of Nutrition and Dietetics KDOQI Clinical Practice Guideline for Nutrition in Chronic Kidney Disease

The Academy of Nutrition and Dietetics and the National Kidney Foundation collaborated to provide an update to the Clinical Practice Guidelines (CPG) for nutrition in chronic kidney disease (CKD). These guidelines provide a valuable update to many aspects of the nutrition care process. They include changes in the recommendations for nutrition screening and assessment, macronutrients, and targets for electrolytes and minerals. The International Society of Renal Nutrition and Metabolism assembled a special review panel of experts and evaluated these recommendations prior to public review. As one of the highlights of the CPG, the recommended dietary protein intake range for patients with diabetic kidney disease is 0.6-0.8 g/kg/day, whereas for CKD patients without diabetes it is 0.55-0.6 g/kg/day. The International Society of Renal Nutrition and Metabolism endorses the CPG with the suggestion that clinicians may consider a more streamlined target of 0.6-0.8 g/kg/day, regardless of CKD etiology, while striving to achieve intakes closer to 0.6 g/kg/day. For implementation of these guidelines, it will be important that all stakeholders work to detect kidney disease early to ensure effective primary and secondary prevention. Once identified, patients should be referred to registered dietitians or the region-specific equivalent, for individualized medical nutrition therapy to slow the progression of CKD. As we turn our attention to the new CPG, we as the renal nutrition community should come together to strengthen the evidence base by standardizing outcomes, increasing collaboration, and funding well-designed observational studies and randomized controlled trials with nutritional and dietary interventions in patients with CKD.

Citric Acid-Containing Dialysate and Survival Rate in the Dialysis Outcomes and Practice Patterns Study

Background

Metabolic acidosis is a common threat for patients on hemodialysis, managed by alkaline dialysate. The main base is bicarbonate, to which small amounts of acetic, citric, or hydrochloric acid are added. The first two are metabolized to bicarbonate, mostly by the liver. Citric acid-containing dialysate might improve dialysis efficiency, anticoagulation, calcification propensity score, and intradialytic hemodynamic stability. However, a recent report from the French dialysis registry suggested this dialysate increases mortality risk. This prompted us to assess whether citric acid-containing bicarbonate-based dialysate was associated with mortality in the international Dialysis Outcomes and Practice Patterns Study (DOPPS).

Methods

Detailed patient-based information on dialysate composition was collected in DOPPS phases 5 and 6 (2012-2017). Cox regression was used to model the association between baseline bicarbonate dialysate containing citric acid versus not containing citric acid and mortality among DOPPS countries and phases where citric acid-containing dialysate was used.

Results

Citric acid-containing dialysate was most commonly used in Japan, Italy, and Belgium (25%, 25%, 21% and of patients who were DOPPS phase 6, respectively) and used in <10% of patients in other countries. Among 11,306 patients in DOPPS country and phases with at least 15 patients using citric acid-containing dialysate, patient demographics, comorbidities, and laboratories were similar among patients using (14%) versus not using (86%) citric acid-containing dialysate. After accounting for case mix, we did not observe a directional association between citric acid-containing dialysate use (any versus none) and mortality (HR, 1.14; 95% CI, 0.97 to 1.34), nor did we find evidence of a dose-dependent relationship when parameterizing the citric acid concentration in the dialysate as 1, 2, and 3+ mEq/L.

Conclusions

The use of citric acid-containing dialysate was not associated with greater risk of all-cause mortality in patients on hemodialysis participating in DOPPS. Clinical indications for the use of citric acid-containing dialysate deserve further investigation.

Self-reported Pruritus and Clinical, Dialysis-Related, and Patient-Reported Outcomes in Hemodialysis Patients

RATIONALE & OBJECTIVE

Chronic kidney disease (CKD)-associated pruritus, generalized itching related to CKD, affects many aspects of hemodialysis patients' lives. However, information regarding the relationship between pruritus and several key outcomes in hemodialysis patients remains limited.

STUDY DESIGN

Prospective cohort.

SETTING & PARTICIPANTS

23,264 hemodialysis patients from 21 countries in the Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 4 to 6 (2009-2018).

EXPOSURE

Pruritus severity, based on self-reported degree to which patients were bothered by itchy skin (5-category ordinal scale from "not at all" to "extremely").

OUTCOMES

Clinical, dialysis-related, and patient-reported outcomes.

ANALYTICAL APPROACH

Cox regression for time-to-event outcomes and modified Poisson regression for binary outcomes, adjusted for potential confounders.

RESULTS

The proportion of patients at least moderately bothered by pruritus was 37%, and 7% were extremely bothered. Compared with the reference group ("not at all"), the adjusted mortality HR for patients extremely bothered by pruritus was 1.24 (95% CI, 1.08-1.41). Rates of cardiovascular and infection-related deaths and hospitalizations were also higher for patients extremely versus not at all bothered by pruritus (HR range, 1.17-1.44). Patients extremely bothered by pruritus were also more likely to withdraw from dialysis and miss hemodialysis sessions and were less likely to be employed. Strong monotonic associations were observed between pruritus severity and longer recovery time from a hemodialysis session, lower physical and mental quality of life, increased depressive symptoms, and poorer sleep quality.

LIMITATIONS

Residual confounding, recall bias, nonresponse bias.

CONCLUSIONS

Our findings demonstrate how diverse and far-reaching poor outcomes are for patients who experience CKD-associated pruritus, specifically those with more severe pruritus. There is need for change in practice patterns internationally to effectively identify and treat patients with pruritus to reduce symptom burden and improve quality of life and possibly even survival.

Measurement of glomerular filtration rate in lung transplant recipients highlights a dramatic loss of renal function after transplantation

BACKGROUND

Chronic kidney disease (CKD) after lung transplantation (LT) is underestimated. The aim of the present study was to measure the loss of glomerular filtration rate (GFR) 1 year after LT and to identify the risk factors for developing Stage ≥3 CKD.

METHODS

LT patients in the University Hospital of Lyon had a pre- and post-transplantation measurement of their GFR (mGFR), and GFR was also estimated using the Chronic Kidney Disease Epidemiology Collaboration equation.

RESULTS

During the study period, 111 patients were lung transplant candidates, of which 91 had a pre-transplantation mGFR, and 29 had a mGFR at 1 year after LT. Six patients underwent maintenance haemodialysis after transplantation. Mean mGFR was 106 mL/min/1.73 m² before LT and 58 mL/min/1.73 m² 1 year after LT (P < 0.05) with a mean loss of 48 mL/min/1.73 m² per patient. The risk of developing Stage ≥3 CKD after LT was higher in patients with lower pre-LT mGFR (odds ratio for each 1 mL/min/1.73 m² increase: 0.94, 95% confidence interval 0.88-0.99). Receiver operator characteristics curves for the sensitivity and specificity of eGFR and mGFR for the prediction of CKD Stage ≥3 after LT found that pre-LT mGFR of 101 mL/min/1.73 m² and pre-LT eGFR of 124 mL/min/1.73 m² were the optimal thresholds for predicting Stage ≥3 CKD after LT.

CONCLUSION

The present study underlines the value of mGFR in the pre-LT stage and found major renal function loss after LT, and consequently two-thirds of patients have Stage ≥3 CKD at 1 year. All patients with a pre-LT mGFR <90 mL/min/1.73 m² warrant particular attention.

CKD Increases Carbonylation of HDL and Is Associated with Impaired Antiaggregant Properties

BACKGROUND

CKD is associated with increased oxidative stress that correlates with occurrence of cardiovascular events. Modifications induced by increased oxidative stress particularly affect circulating lipoproteins such as HDL that exhibit antiatheromatous and antithrombotic properties in vitro.

METHODS

To explore the specific role of oxidative modifications of HDL in CKD and their effect on the platelet-targeting antiaggregant properties of HDL, we used a CKD (5/6 nephrectomy) rabbit model. For ex vivo assessment of the antiaggregant properties of HDL, we collected blood samples from 15 healthy volunteers, 25 patients on hemodialysis, and 20 on peritoneal dialysis. We analyzed malondialdehyde, 4-hydroxynonenal (HNE), and 4-hydroxy-2-hexenal protein adduct levels. Platelet aggregation and activation were assessed by aggregometry, thromboxane B2 assay, or FACS. We modified HDL from controls by incubating it overnight at 37°C with 100 µM of HNE.

RESULTS

HDL from CKD rabbits and patients on hemodialysis had HNE adducts. The percentage of platelet aggregation or activation induced by collagen was significantly higher when platelets were incubated with HDL from CKD rabbit and hemodialysis groups than with HDL from the control group. In both rabbits and humans, platelet aggregation and activation were significantly higher in the presence of HNE-modified HDL than with HDL from their respective controls. Incubation of platelets with a blocking antibody directed against CD36 or with a pharmacologic inhibitor of SRC kinases restored the antiaggregative phenotype in the presence of HDL from CKD rabbits, patients on hemodialysis and peritoneal dialysis, and HNE-modified HDL.

CONCLUSIONS

HDL from CKD rabbits and patients on hemodialysis exhibited an impaired ability to inhibit platelet aggregation, suggesting that altered HDL properties may contribute to the increased cardiovascular risk in this population.

P0536HYPOTHERMIA DURING RENAL ISCHEMIA-REPERFUSION IN MICE: A PROTECTIVE EFFECT ON RENAL AND MITOCHONDRIAL FUNCTIONS

Background and Aims

Renal ischemia reperfusion (RIR) can induce mitochondrial stress triggering cell death and eventually leading to acute kidney injury (AKI). It has been suggested that mild hypothermia could be protective in RIR without clear underlying mechanisms. We aimed to show that mild hypothermia (34°C) during RIR protects renal mitochondrial function and prevents AKI.

Method

Male C57BL6 mice were assigned to 4 groups: normothermic ischemic (RIR-37°C) group (n=14) and hypothermic ischemic (RIR-34°C) group (n=14) with body temperature maintained at respectively 37°C or 34°C during 20 minutes of renal ischemia by bilateral renal clamping under general anesthesia; normothermic sham (Sham-37°C) group (n=10) and hypothermic sham (Sham-34°C) group (n=10) with only anesthesia and laparotomy at 37°C or 34°C respectively. Renal function (serum urea concentration) and isolated renal mitochondria function (capacity of mitochondria to retain calcium i.e. calcic retention capacity (CRC), and oxidative phosphorylation capacity of electron transport chain complexes (complex I, II and IV)) were assessed 2 hours and 24 hours after reperfusion. All animal procedures were approved by local Ethics Committee. Data are presented as median with IQR.

Results

All the parameters monitored were not modified by the temperature in the sham groups, and there was no mortality in those 2 groups. Mortality was 33% in the RIR-37°C group and 11% in the RIR-34°C group 24 hours after reperfusion (p=0.58).

Renal ischemia was responsible for a significant increase of serum urea level 2 hours after reperfusion at 37°C [18.7 (17.3–19.0) mmol/L] compared to sham groups (p=0.02), whereas no significant increase was observed in the RIR-34°C group. After 24 hours of reperfusion serum urea level was improved in the RIR-34°C group [22.7 (11.5–42.0) mmol/L] compared to RIR-37°C [60.8 (58.0–69.7) mmol/L, p=0.001].

CRC was not modified by RIR after 2 hours of reperfusion in both groups. CRC was preserved 24 hours after reperfusion in the RIR-34°C group [260 (210–320) nmol Ca2+/mg protein] with no difference compared to Sham-37°C [320 (280–360) nmol Ca2+/mg protein p=0.18] whereas CRC was significantly decreased in the RIR-37°C group compared to Sham-37°C [120 (0–130) vs 320 (280–360) nmol Ca2+/mg protein p=0.004).

Complexes I, II and IV were lowered after 2 hours of reperfusion in the RIR-37°C group (p&lt;0.05), and complexes II and IV activities remained altered 24 hours after reperfusion, compared to Sham-37°C (p=0.009 and p=0.02 respectively). In the RIR-34°C group, complexes I, II and IV activities were preserved 2 hours after reperfusion but complex I activity decreased 24 hours after reperfusion. We found significant difference between complexes II and IV activities between IRI-34°C and RIR-37°C.

Conclusion

Mild hypothermia (34°C) during RIR significantly protected renal mitochondrial respiration and mitochondrial stress, associated with a preserved renal function after 2 hours of reperfusion and an improved renal function 24 hours after reperfusion compared to normothermic mice (37°C).

Estimated Glomerular Filtration Rate Bias in Participants with Severe Obesity Regardless of Deindexation

OBJECTIVE

Morbid obesity is associated with a higher independent risk of chronic kidney disease (CKD). Estimated glomerular filtration rate (eGFR) has been evaluated in a limited number of study participants with severe obesity.

METHODS

A total of 706 measured GFR (mGFR) results from 598 participants with obesity (BMI ≥ 35 kg/m² ) were retrospectively collected. The performance of the Modification of Diet in Renal Disease (MDRD) equation, Chronic Kidney Disease-Epidemiology (CKD-EPI) equation, and deindexed eGFR were compared with mGFR from the gold standard technique (inuline or iohexol), adjusted (mGFRr) or nonadjusted (mGFR) to body surface area. Absolute bias, precision, and accuracy were calculated.

RESULTS

Mean mGFRr (58 ± 31 mL/min/1.73 m² ) was significantly different from CKD-EPI and MDRD (P < 0.001). Mean mGFR (nonindexed) (70 ± 40 mL/min) was significantly higher than mGFRr (P < 0.001). eGFR showed important biases and low accuracies for CKD-EPI and MDRD (10.7 ± 10.7 and 12.2 ± 13.7 mL/min/1.73 m² ; 78% vs. 75% respectively). Deindexation worsened bias and accuracy 30% (percentage of GFR estimates within 30% of mGFRr or mGFR) between eGFR and mGFR.

CONCLUSIONS

eGFR overestimates mGFR and is associated with important biases and inaccuracies in patients with severe obesity, and deindexing eGFR worsens the overestimation. These findings may have important implications in examining kidney function in patients with obesity.

Elevation of Trimethylamine-N-Oxide in Chronic Kidney Disease: Contribution of Decreased Glomerular Filtration Rate

Gut microbiota-dependent Trimethylamine-N-oxide (TMAO) has been reported to be strongly linked to renal function and to increased cardiovascular events in the general population and in Chronic Kidney Disease (CKD) patients. Considering the lack of data assessing renal handling of TMAO, we conducted this study to explore renal excretion and mechanisms of accumulation of TMAO during CKD. We prospectively measured glomerular filtration rate (mGFR) with gold standard methods and plasma concentrations of trimethylamine (TMA), TMAO, choline, betaine, and carnitine by LC-MS/MS in 124 controls, CKD, and hemodialysis (HD) patients. Renal clearance of each metabolite was assessed in a sub-group of 32 patients. Plasma TMAO was inversely correlated with mGFR (r² = 0.388, p < 0.001), confirming elevation of TMAO plasma levels in CKD. TMAO clearances were not significantly different from mGFR, with a mean ± SD TMAO fractional excretion of 105% ± 32%. This suggests a complete renal excretion of TMAO by glomerular filtration with a negligible participation of tubular secretion or reabsorption, during all stages of CKD. Moreover, TMAO was effectively removed within 4 h of hemodiafiltration, showing a higher fractional reduction value than that of urea (84.9% ± 6.5% vs. 79.2% ± 5.7%, p = 0.04). This study reports a strong correlation between plasma TMAO levels and mGFR, in CKD, that can be mainly related to a decrease in TMAO glomerular filtration. Clearance data did not support a significant role for tubular secretion in TMAO renal elimination.

ICU survival and need of renal replacement therapy with respect to AKI duration in critically ill patients

BACKGROUND

Transient and persistent acute kidney injury (AKI) could share similar physiopathological mechanisms. The objective of our study was to assess prognostic impact of AKI duration on ICU mortality.

DESIGN

Retrospective analysis of a prospective database via cause-specific model, with 28-day ICU mortality as primary end point, considering discharge alive as a competing event and taking into account time-dependent nature of renal recovery. Renal recovery was defined as a decrease of at least one KDIGO class compared to the previous day.

SETTING

23 French ICUs.

PATIENTS

Patients of a French multicentric observational cohort were included if they suffered from AKI at ICU admission between 1996 and 2015.

INTERVENTION

None.

RESULTS

A total of 5242 patients were included. Initial severity according to KDIGO creatinine definition was AKI stage 1 for 2458 patients (46.89%), AKI stage 2 for 1181 (22.53%) and AKI stage 3 for 1603 (30.58%). Crude 28-day ICU mortality according to AKI severity was 22.74% (n = 559), 27.69% (n = 327) and 26.26% (n = 421), respectively. Renal recovery was experienced by 3085 patients (58.85%), and its rate was significantly different between AKI severity stages (P < 0.01). Twenty-eight-day ICU mortality was independently lower in patients experiencing renal recovery [CSHR 0.54 (95% CI 0.46-0.63), P < 0.01]. Lastly, RRT requirement was strongly associated with persistent AKI whichever threshold was chosen between day 2 and 7 to delineate transient from persistent AKI.

CONCLUSIONS

Short-term renal recovery, according to several definitions, was independently associated with higher mortality and RRT requirement. Moreover, distinction between transient and persistent AKI is consequently a clinically relevant surrogate outcome variable for diagnostic testing in critically ill patients.

Use of rituximab as an induction therapy in anti-glomerular basement-membrane disease

BACKGROUND

Anti-glomerular basement-membrane (anti-GBM) disease (or Goodpasture disease) is characterized by severe kidney and lung involvement. Prognoses have improved with treatments that combine plasma exchange and immunosuppressive drugs. However, patients with severe renal involvement can have poor renal outcomes and cyclophosphamide can cause significant complications. Anti-GBM antibodies have a direct pathogenic effect on the disease: thus, therapeutics that can decrease their production, such as rituximab, could be a good alternative.

METHODS

The medical files of five patients that had received rituximab as a first-line therapy (instead of cyclophosphamide), plus plasma exchange and steroids, were reviewed. All patients had severe disease manifestations.

RESULTS

Four patients required dialysis at diagnosis and remained dialysis-dependent over the mean follow-up of 15 months. Three patients had pulmonary involvement, but recovered even though mechanical ventilation was required. Anti-GBM antibodies became rapidly undetectable in all patients. One infectious and two hematological complications were observed.

CONCLUSIONS

We report the outcomes of five patients with Goodpasture disease and treated with rituximab as a first-line treatment. This strategy was effective at treating pulmonary manifestations and was associated with a good biological response with no major serious adverse events. However, renal outcomes were not significantly improved.

[The future of kidney failure treatments]

The future of nephrology lies in the miniaturisation of renal replacement techniques, the development of the use of stem cells and xenotransplants. Moreover, medicine must be personalised, from screening and throughout the care pathway of the patient with chronic kidney failure. Thereby, the risk of morbidity can be reduced and the quality of life improved, with the help of connected tools. The role of the patients themselves and all healthcare professionals is essential.

Pregnancy Outcomes in French Hemodialysis Patients

BACKGROUND

Pregnancy in hemodialysis (HD) women is a rare event and often associated with maternal and fetal complications. Scarcity of available data from large cohorts impedes fair medical counseling.

METHODS

This is a descriptive, retrospective, multi-centric study. Pregnant women on HD during the period from 1985 to 2015 in France were included. The primary outcome was a living infant discharged from hospital, while secondary outcomes included gestational age and birth weight.

RESULTS

We identified 100 pregnancies in 84 women on HD, from 41 centers. Chronic HD was initiated during pregnancy for 17.7% (14/79) of patients explaining a 19.8% prevalence of catheter (19/96) and a preserved residual diuresis for 50% of pregnancy (43/86). Seventy-six (89.4%) women performed daily dialysis during the third trimester (6 times per week). Our primary outcome was met for 78% of newborns with a mean gestational age of 33.2 ± 3.9 weeks and a mean birth weight of 1,719 ± 730 g.

CONCLUSIONS

Our study is one of the largest series of -pregnancies in HD patients. Despite recent progresses, these pregnancies remain at high risk, reinforcing the need for an early nephrologist-obstetrician skilled team co-management.

Renal Involvement in Neuropathy, Ataxia, Retinitis Pigmentosa (NARP) Syndrome: A Case Report

We report a case of a patient who had the mitochondrial cytopathy complex of neuropathy, ataxia, and retinitis pigmentosa (NARP) syndrome diagnosed at age 11 years with a biopsy-proven kidney involvement that progressed to end-stage renal disease at age 21 years. Mutations of mitochondrial DNA (mtDNA) are maternally inherited and lead to mitochondrial cytopathies with predominant neurologic manifestations: psychomotor retardation, epilepsy, ataxia, neuropathy, and myopathy. Given the ubiquitous nature of mitochondria, cellular dysfunction can also appear in tissues with high metabolic turnover; thus, there can be cardiac, digestive, ophthalmologic, and kidney complications. Mutations in the MT-ATP6 gene of mtDNA have been shown to cause NARP syndrome without renal involvement. We report a patient who had NARP syndrome diagnosed at age 11 years in whom glomerular proteinuria was present very early after diagnosis. Although neurologic manifestations were stable over time, he developed worsening proteinuria and kidney function. He started dialysis therapy at age 21 years. Kidney biopsy confirmed the mitochondrial cytopathy histologically, with abnormal mitochondria seen on electron microscopy. The MT-ATP6 gene mutation was detected in the kidney biopsy specimen.

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.

The Relationship Between Body Composition and Bone Quality Measured with HR-pQCT in Peritoneal Dialysis Patients

BACKGROUND

Bone is known to be impaired in chronic kidney disease and dialysis patients. Recent studies have shown that body composition (fat mass and lean mass) may impact bone health. Some of these effects may be related to mediators that are secreted by adipose tissue.

METHODS

The aim of this study was to evaluate the association between body composition (dual x-ray absorptiometry [DEXA]) and adipokines (leptin, adiponectin), with bone density and microarchitecture assessed with high-resolution peripheral quantitative computed tomography (HR-pQCT) in chronic peritoneal dialysis (PD) patients in a single-center prospective study.

RESULTS

Twenty-three patients with a median age of 61 years and body mass index (BMI) of 27 kg/m² were recruited. On univariate analysis, age was negatively associated with total volumetric bone mineral density (vBMD) (r = -0.75, p < 0.01), cortical vBMD (r = -0.85, p < 0.01), and cortical thickness (r = -0.71, p < 0.01). There was a negative association between leptin and cortical thickness (r = -0.48, p = 0.021). Fat mass (FM) was negatively correlated with cortical thickness (r = -0.52, p = 0.012). No association was found between bone parameters and dialysis duration, serum insulin, intact parathyroid hormone, osteocalcin, and adiponectin. The short dialysis vintage could in part explain the lack of correlation with bone parameters. In multivariate analysis, FM was significantly and negatively correlated with total vBMD, cortical and trabecular thickness.

CONCLUSIONS

These data suggest that FM is negatively associated with bone quality in PD patients, supporting a relation between body composition and bone that is independent from other dialysis-associated complications. The relative contribution of the different fat deposits (visceral versus subcutaneous) needs to be assessed in future studies.

PBX1 haploinsufficiency leads to syndromic congenital anomalies of the kidney and urinary tract (CAKUT) in humans

BACKGROUND

Congenital anomalies of the kidney and urinary tract (CAKUT) represent a significant healthcare burden since it is the primary cause of chronic kidney in children. CNVs represent a recurrent molecular cause of CAKUT but the culprit gene remains often elusive. Our study aimed to define the gene responsible for CAKUT in patients with an 1q23.3q24.1 microdeletion.

METHODS

We describe eight patients presenting with CAKUT carrying an 1q23.3q24.1 microdeletion as identified by chromosomal microarray analysis (CMA). Clinical features were collected, especially the renal and urinary tract phenotype, and extrarenal features. We characterised PBX1 expression and localisation in fetal and adult kidneys using quantitative RT-PCR and immunohistochemistry.

RESULTS

We defined a 276-kb minimal common region (MCR) that only overlaps with the PBX1 gene. All eight patients presented with syndromic CAKUT. CAKUT were mostly bilateral renal hypoplasia (75%). The most frequent extrarenal symptoms were developmental delay and ear malformations. We demonstrate that PBX1 is strongly expressed in fetal kidneys and brain and expression levels decreased in adult samples. In control fetal kidneys, PBX1 was localised in nuclei of medullary, interstitial and mesenchymal cells, whereas it was present in endothelial cells in adult kidneys.

CONCLUSIONS

Our results indicate that PBX1 haploinsufficiency leads to syndromic CAKUT as supported by the Pbx1-null mice model. Correct PBX1 dosage appears to be critical for normal nephrogenesis and seems important for brain development in humans. CMA should be recommended in cases of fetal renal anomalies to improve genetic counselling and pregnancy management.

Chronic Lyme borreliosis associated with minimal change glomerular disease: a case report

BACKGROUND

There are only few cases of renal pathology induced by Lyme borreliosis in the literature, as this damage is rare and uncommon in humans. This patient is the first case of minimal change glomerular disease associated with chronic Lyme borreliosis.

CASE PRESENTATION

A 65-year-old Caucasian woman was admitted for an acute edematous syndrome related to a nephrotic syndrome. Clinical examination revealed violaceous skin lesions of the right calf and the gluteal region that occurred 2 years ago. Serological tests were positive for Lyme borreliosis and skin biopsy revealed lesions of chronic atrophic acrodermatitis. Renal biopsy showed minimal change glomerular disease. The skin lesions and the nephrotic syndrome resolved with a sequential treatment with first ceftriaxone and then corticosteroids.

CONCLUSION

We report here the first case of minimal change disease associated with Lyme borreliosis. The pathogenesis of minimal change disease in the setting of Lyme disease is discussed but the association of Lyme and minimal change disease may imply a synergistic effect of phenotypic and bacterial factors. Regression of proteinuria after a sequential treatment with ceftriaxone and corticosteroids seems to strengthen this conceivable association.

Prevention of diet-induced hepatic steatosis and hepatic insulin resistance by second generation antisense oligonucleotides targeted to the longevity gene mIndy (Slc13a5)

Reducing the expression of the Indy (I'm Not Dead Yet) gene in lower organisms extends life span by mechanisms resembling caloric restriction. Similarly, deletion of the mammalian homolog, mIndy (Slc13a5), encoding for a plasma membrane tricarboxylate transporter, protects from aging- and diet-induced adiposity and insulin resistance in mice. The organ specific contribution to this phenotype is unknown. We examined the impact of selective inducible hepatic knockdown of mIndy on whole body lipid and glucose metabolism using 2′-O-methoxyethyl chimeric anti-sense oligonucleotides (ASOs) in high-fat fed rats. 4-week treatment with 2′-O-methoxyethyl chimeric ASO reduced mIndy mRNA expression by 91% (P<0.001) compared to control ASO. Besides similar body weights between both groups, mIndy-ASO treatment lead to a 74% reduction in fasting plasma insulin concentrations as well as a 35% reduction in plasma triglycerides. Moreover, hepatic triglyceride content was significantly reduced by the knockdown of mIndy, likely mediating a trend to decreased basal rates of endogenous glucose production as well as an increased suppression of hepatic glucose production by 25% during a hyperinsulinemic-euglycemic clamp. Together, these data suggest that inducible liver-selective reduction of mIndy in rats is able to ameliorate hepatic steatosis and insulin resistance, conditions occurring with high calorie diets and during aging.

Cystatin C-Creatinine Based Glomerular Filtration Rate Equation in Obese Chronic Kidney Disease Patients: Impact of Deindexation and Gender

BACKGROUND

Cystatin C is considered an alternative to creatinine to estimate glomerular filtration rate (GFR). However, studies have reported that increased adiposity is associated with a higher level of circulating cystatin C questioning the performance of estimation of GFR using cystatin C in obese subjects.

METHODS

We prospectively included 166 obese stages 1-5 chronic kidney disease (CKD) patients between 2013 and 2015. GFR was measured with a reference method without (measured GFR [mGFR]) and with adjustment to body surface area (mGFRr) and estimated (eGFR) or de-indexed eGFR using the Chronic Kidney Disease and Epidemiology (CKD-EPI) equation using creatinine (CKD-EPIcreat), cystatin (CKD-EPIcyst) and the combination of cystatin and creatinine (CKD-EPIcyst-creat).

RESULTS

The biases between mGFR and de-indexed CKD-EPIcyst-creat were significantly lower than de-indexed CKD-EPIcreat (p = 0.001). Accuracies were significantly better with de-indexed CKD-EPIcyst-creat compared to CKD-EPIcreat and CKD-EPIcyst, respectively (p = 0.04 and 0.03). Bland and Altman plot showed a great dispersion of all formulae when patients had a GFR >60 ml/min. Interestingly, there is a gender difference; biases, precisions and accuracies of de-indexed CKD-EPIcyst-creat were significantly lower in obese women. These results may be related to a difference in the change of body composition during obesity in men versus women and in fact only waist circumference (WC) was positively and significantly correlated with cystatin C (p < 0.0001) whereas body mass index (BMI; p = 0.3) was not; bias for CKD-EPIcyst-creat was related with WC.

CONCLUSION

Cystatin C-creatinine-based GFR equations outperform creatinine-based formula in obese CKD patients especially those with BMI ≥35 and in obese women.

Serum sclerostin: the missing link in the bone-vessel cross-talk in hemodialysis patients?

We found for the first time that in maintenance hemodialysis patients, higher sclerostin serum level was associated with severe abdominal aortic calcification (AAC). In addition, cortical bone microarchitecture (density and thickness) assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT) at tibia was also independently associated with severe AAC. These results suggest that sclerostin may be involved in the association of mineral and bone disorder with vascular calcification in hemodialysis patients.

INTRODUCTION

Severe abdominal aortic calcifications are predictive of high cardiovascular mortality in maintenance hemodialysis (MHD) patients. In patients with end-stage renal disease, a high aortic calcification score was associated with lower bone turnover on bone biopsies. Thus, we hypothesized that sclerostin, a Wnt pathway inhibitor mainly secreted by osteocytes and acting on osteoblasts to reduce bone formation, may be associated with vascular calcifications in MHD patients.

METHODS

Fifty-three MHD patients, aged 53 years [35-63] (median [Q1-Q3]) were included. Serum was sampled before the MHD session to assay sclerostin. Framingham score was computed and the abdominal aortic calcification (AAC) score was assessed according to Kauppila method on lateral spine imaging using DEXA. Tibia bone status was evaluated by high-resolution peripheral quantitative computed tomography (HR-pQCT). Patients were distributed into two groups according to their AAC score: patients with mild or without AAC (score below 6) versus patients with severe AAC (score of 6 and above).

RESULTS

In multivariate analysis, after adjustment on age, dialysis duration and diabetes, serum sclerostin and cortical thickness were independently associated with severe AAC (odds ratio (OR) = 1.43 for each 0.1 ng/mL increase [95 % confidence interval (CI) 1.10-1.83]; p = 0.006 and 0.16 for 1 SD increase [0.03-0.73]; p = 0.018, respectively). A second cardiovascular model adjusted on Framingham score and the above mentioned confounders showed similar results.

CONCLUSIONS

Elevated sclerostin serum level and poorer tibia cortical bone structure by HR-pQCT were positively and independently associated with higher odds of severe AAC in MHD patients. Serum sclerostin may become a biomarker of mineral and bone disorder and vascular risk in MHD patients.