Localized recharge processes in the NE Mekong Delta and implications for groundwater quality

Understanding recharge in the Mekong Delta is critical for the delta's groundwater resources, and requires the investigation of recharge processes at the local scale. In this study of the north eastern area of the Mekong Delta, time-series of environmental tracer data (δ¹⁸O, δ²H, major ions and ³H) and markers of rural pollution (NH₄ and NO₃) were used to highlight localized recharge and impacts on groundwater quality. Results highlighted new hydrological insights into recharge processes, including that the Pleistocene aquifer receives recent recharge (< 60 years), predominantly during high rainfall months (> 100 mm/month). However, due to shallow clay layers there are significant spatial variations in these recharge processes, which were observed in the seasonal fluctuation of groundwater δ¹⁸O values in groundwater. Wet season δ¹⁸O changes ranged from below analytical uncertainty (≤ 0.10 ‰) to up to 0.56 ‰, and the calculated fraction of rainfall contribution to the aquifer is ≤5 % to 16 %. Rainfall recharge via the acrisol soils results in low groundwater EC (20-55 μS/cm), acidic groundwater (pH 3.6-5.6), and may also have resulted in the low groundwater NO₃ concentrations (≤ 5.3 mg NO₃/L) at many sites due to adsorption, therefore delaying not reducing NO₃ contamination. Site specific variations in nitrogen processes includes increased NO₃ (to 29.7 mg/L) from fertiliser transfers or nitrification, and increased NH₄ (to 1.4 mg/L) likely due to the recharge of irrigation waters. Unlike other recharge areas across the northern Mekong Delta, this north-eastern region provides a groundwater resource unaffected by arsenic contamination. Therefore, these results should inform on priority areas for protection from further contamination by rural anthropogenic activities.

Assessing the hydrogeological resilience of a groundwater-dependent Mediterranean peatland: Impact of global change and role of water management strategies

Mediterranean peatlands remain largely under-documented, except for detailed biological data such as fauna and flora taxa lists, and yet are increasingly threatened by water withdrawal and agriculture practices. This lack of information, particularly on their hydrogeological functioning, makes it impossible to evaluate their response to changing climate conditions. A pilot study on a representative Mediterranean peatland on the island of Corsica (France) was conducted to evaluate recharge modalities in the peatland using a coupled water-level monitoring, geochemical and isotope multi-tracing approach (electric conductivity, major ions, δ¹⁸O, δ²H, ³H, ⁸⁷Sr/⁸⁶Sr). The goal was to understand how water budgets in peatland ecosystems were maintained throughout the year, especially during the summer. Despite the remarkable stability of the peatland water level, the recharge contributions of varied water bodies through an alluvial aquifer vary significantly from one season to another. An end-member mixing analysis (EMMA) indicates that the peatland is mainly recharged by an alluvial aquifer. During fall-winter, the alluvial aquifer on which the peatland depends is recharged by the rainfall, a river, and shallow groundwater (colluvium). During spring-summer, water supply is provided mostly by a river, shallow, and deep groundwater (fractured granite). However, this specific hydrogeological functioning is not taken into account by environmental management policies making peatlands vulnerable to anthropogenic and climatic pressures. Thus, their actual status regarding water and aquatic environment management policies is discussed to provide recommendations for better consideration and preservation.

Seasonal influences on groundwater arsenic concentrations in the irrigated region of the Cambodian Mekong Delta

Similar to many southern and southeast Asian regions, the mobilisation of arsenic (As) from sediments has driven a widespread contamination problem for groundwater resources in the Cambodian Mekong Delta. For the first time, the seasonal changes in As concentrations and potential links to groundwater pumping for irrigation in shallow aquifers of the Cambodian Mekong Delta are investigated. Using environmental tracers (δ¹⁸O, δ²H, ³H, major/trace ions and rare earth elements) the natural and pumping-induced changes in hydrogeological processes are identified. Three conceptual models are proposed: Model 1, where there is limited local recharge or low recharge rates (³H mean residence time > 60 years) and groundwater has a large range in As concentrations (0.2 to 393.8 μg/L). In this semi-confined aquifer, only one of the six groundwater sites has As concentrations that increase (by 10.9 μg/L) potentially due to groundwater pumping and resultant mixing with high-As and low (Pr/Sm)_NASC groundwater. However, data on groundwater extraction volumes is required to verify the link with irrigation practices. Model 2, where groundwater is recharged by evaporated surface waters (fractionated δ¹⁸O and δ²H). There are moderate As concentrations (64.1-106.1 μg/L) but no significant seasonal changes even though the recharging waters have relatively greater organic carbon contents during the dry season (reduced Ce/Ce*anomaly). Finally model 3, where groundwater is significantly recharged by wet season rainfall (~50% from δ¹⁸O data). There is a minor increase in As concentrations with recharge (by 6. μg/L). These combined results highlight an aquifer system in the irrigated region of the Cambodian Mekong Delta where As concentrations are largely impacted by natural rather than irrigation processes. Seasonal-scale recharge processes control As processes where the aquifer is not confined by shallow clay layers, and where the aquifer is semi-confined As concentrations largely reflect longer-term natural processes.

Topotactic desolvation and condensation reactions of 3D Zn3TiF7(H2O)2(taz)3·S (S = 3H2O or C2H5OH)

Thermodiffraction, IR, DFT calculations, and ¹H and ¹⁹F NMR characterizations of the desolvatation and reversible condensation reactions of Zn₃TiF₇(taz)₃ family.

Strong magnetic exchange and frustrated ferrimagnetic order in a weberite-type inorganic-organic hybrid fluoride

We combine powder neutron diffraction, magnetometry and ⁵⁷Fe Mössbauer spectrometry to determine the nuclear and magnetic structures of a strongly interacting weberite-type inorganic-organic hybrid fluoride, Fe₂F₅(H taz). In this structure, Fe²⁺ and Fe³⁺ cations form magnetically frustrated hexagonal tungsten bronze layers of corner-sharing octahedra. Our powder neutron diffraction data reveal that, unlike its purely inorganic fluoride weberite counterparts which adopt a centrosymmetric Imma structure, the room-temperature nuclear structure of Fe₂F₅(H taz) is best described by a non-centrosymmetric Ima2 model with refined lattice parameters a = 9.1467(2) Å, b = 9.4641(2) Å and c = 7.4829(2) Å. Magnetic susceptibility and magnetization measurements reveal that strong antiferromagnetic exchange interactions prevail in Fe₂F₅(H taz) leading to a magnetic ordering transition at T_N = 93 K. Analysis of low-temperature powder neutron diffraction data indicates that below T_N, the Fe²⁺ sublattice is ferromagnetic, with a moment of 4.1(1) µ_B per Fe²⁺ at 2 K, but that an antiferromagnetic component of 0.6(3) µ_B cants the main ferromagnetic component of Fe³⁺, which aligns antiferromagnetically to the Fe²⁺ sublattice. The zero-field and in-field Mössbauer spectra give clear evidence of an excess of high-spin Fe³⁺ species within the structure and a non-collinear magnetic structure. This article is part of the theme issue 'Mineralomimesis: natural and synthetic frameworks in science and technology'.

Native Arterio-Venous Fistula for Hemodialysis: What to Expect Early after Creation?

Native arterio-venous fistulas (AVFs) are preferred for hemodialysis vascular access over synthetic grafts and long-term catheters. However, prevalence rates of native AVFs are variable around the world and have increased only slightly in United States since the DOQI guidelines. To increase rates of native AVFs, pre-operative vascular mapping by ultrasound has been found of major help for appropriate selection of the vessels. The minimal desirable lumen diameter of the artery should be > 2 mm and > 2.5 to 3 mm for the vein at the anatomosis. Early failure can be reduced to less than 10% when the feeding artery is > 2 mm, even in diabetics. If sizes of the vessels are smaller than those targets at the wrist, moving to the upper arm should be considered. The interval between creation and first cannulation varies from 2 weeks to 4 months. There might not be much advantage to wait for more than 4 weeks; however, in large dialysis units, observing a delay of 4 to 6 weeks may be worthwhile to avoid initial problems such as infiltrations and lacerations. Access flow monitoring is essential since it is a reliable predictor of vascular access dysfunction, reducing associated morbidity and costs. Early monitoring of recently created native AVFs has shown that the increase in intra-access blood flow occurs very soon after construction and becomes maximal after a few weeks. A recent prospective study involving all new native AVFs monitored by ultrasound-dilution between weeks 6 and 10 after creation, and every 3 to 6 weeks over 4 months, showed no statistically significant difference in access blood flow between the initial and final measurements (respective values of 1132 ± 681 and 1097 ± 644 ml/min). Access flow was higher in males, and in brachio-cephalic compared to radio-cephalic AVFs. Over the long-term, AVFs are associated with longer patency and lower complication rates, and efforts should be directed at further increasing their prevalence.

Impact of irrigated agriculture on groundwater resources in a temperate humid region

The groundwater irrigation expansion, and its multiple potential impacts on the quantity and quality of water resources, is not just restricted to areas that are water limited. In this study we present the seasonal impacts irrigation practices can have on groundwater resources in a temperate humid region, where the average annual rain/PET ratio is 1.0. In this system the irrigation expansion is solely supported by groundwater pumping, but despite this only 5 boreholes are monitored for hydraulic head data. In this study, we compensate the scarce hydrophysical dataset by incorporating environmental tracers (major ions, δ¹⁸O, δ²H and δ¹³C) and dating tracers (³H, CFC, SF₆ and ¹⁴C). Results indicate that at 9 of the 15 irrigation sites investigated, groundwater pumping for irrigation has induced the mixing of recent groundwater (up to <1year) with older waters. The origin of the older waters was from either the deeper marl aquifer, or the shallow sand-clay aquifer (SCB) that has a ¹⁴C mean residence time (MRT) of up to 9700years. Secondly, although high nitrate loads in infiltrating waters were being diverted via the artificial subsurface drainage system, increases in fertiliser loads have resulted in higher NO₃ concentrations in younger groundwater (NO₃: 9-45mg/L, MRT <20years), compared with older groundwater (NO₃≤9mg/L, MRT>20years). The changes in flow pathways, induced by irrigation, also results in seasonal declines in groundwater NO₃ concentrations due to mixing with older waters. In temperate humid areas, such evaluations of the seasonal evolution of water residence time, mixing process, and agrochemical contaminants are an important contribution to real water resources management in irrigated catchments.

Volume Management by Renal Replacement Therapy in Acute Kidney Injury

Management of fluid balance is one of the basic but vital tasks in the care of critically ill patients. Hypovolemia results in a decrease in cardiac output and tissue perfusion and may lead to progressive multiple organ dysfunction, including the development of acute renal injury (AKI). However, in an effort to reverse pre-renal oliguria, it is not uncommon for patients with established oliguric acute renal failure, particularly when associated with sepsis, to receive excessive fluid resuscitation, leading to fluid overload. In patients with established oliguria, renal replacement therapy may be required to treat hypervolemia. Safe prescription of fluid loss during RRT requires intimate knowledge of the patient's underlying condition, understanding of the process of ultrafiltration and close monitoring of the patient's cardiovascular response to fluid removal. To preserve tissue perfusion in patients with AKI, it is important that RRT be prescribed in a way that optimizes fluid balance by removing fluid without compromising the effective circulating fluid volume. In patients who are clinically fluid overloaded, it is equally important that the amount of fluid removed be as exact as possible. Fluid balance errors can occur as a result of inappropriate prescription, operator error or machine error. Some CRRT machines have potential for significant fluid errors if alarms can be overridden. Threshold values for fluid balance error have been developed which can be used to predict the severity of harm. It is important that RRT education programs emphasize the risk associated with fluid balance errors and with overriding machine alarms.

Association of Neutrophil-to-Lymphocyte Ratio With Inflammation and Erythropoietin Resistance in Chronic Dialysis Patients

Background

Neutrophil-to-lymphocyte ratio (NLR) was widely studied as a prognostic marker in various medical and surgical specialties, but its significance in nephrology is not yet established.

Objective

We evaluated its accuracy as an inflammation biomarker in a dialysis population.

Design setting

Single-center retrospective study.

Patients

The records of all 550 patients who were treated with hemodialysis (HD) or peritoneal dialysis (PD) from September 2008 to March 2011 were included.

Measurements

NLR was calculated from the monthly complete blood count.

Methods

Association between NLR and markers of inflammation (C-reactive protein [CRP], serum albumin, and erythropoietin resistance index [ERI]) was measured using Spearman coefficient.

Results

In total, 120 patients were eligible for the correlation analyses. We found a positive correlation between NLR and CRP (all patients: r = 0.45, P < .001; HD: r = 0.47, P < .001; PD: r = 0.48, P = .13). NLR and albumin were inversely correlated (r = -0.51, P < .001). Finally, high NLR was associated with a nonsignificant increased ERI, but we have not demonstrated a direct correlation.

Limitations

CRP and albumin are not measured routinely and were ordered for a specific clinical reason leading to an indication bias. Also, no relationship with clinical outcome was established.

Conclusions

NLR seems to be a good inflammatory biomarker in dialysis in addition to being easily available. However, controlled studies should be conducted to properly assess and validate NLR levels that would be clinically significant and relevant, as well as its prognostic significance and utility in a clinical setting.

Safety of low-molecular-weight heparin compared to unfractionated heparin in hemodialysis: a systematic review and meta-analysis

BACKGROUND

Low molecular weight heparins (LMWH) have been extensively studied and became the treatment of choice for several indications including pulmonary embolism. While their efficacy in hemodialysis is considered similar to unfractionated heparin (UFH), their safety remains controversial mainly due to a risk of bioaccumulation in patients with renal impairment. The aim of this systematic review was to evaluate the safety of LMWH when compared to UFH for extracorporeal circuit (ECC) anticoagulation.

METHODS

We used Pubmed, Embase, Cochrane central register of controlled trials, Trip database and NICE to retrieve relevant studies with no language restriction. We looked for controlled experimental trials comparing LMWH to UFH for ECC anticoagulation among end-stage renal disease patients undergoing chronic hemodialysis. Studies were kept if they reported at least one of the following outcomes: bleeding, lipid profile, cardiovascular events, osteoporosis or heparin-induced thrombocytopenia. Two independent reviewers conducted studies selection, quality assessment and data extraction with discrepancies solved by a third reviewer. Relative risk and 95% CI was calculated for dichotomous outcomes and mean weighted difference (MWD) with 95% CI was used to pool continuous variables.

RESULTS

Seventeen studies were selected as part of the systematic. The relative risk for total bleeding was 0.76 (95% CI 0.26-2.22). The WMD calculated for total cholesterol was -28.70 mg/dl (95% CI -51.43 to -5.98), a WMD for triglycerides of -55.57 mg/dl (95% CI -94.49 to -16.66) was estimated, and finally LDL-cholesterol had a WMD of -14.88 mg/dl (95% CI -36.27 to 6.51).

CONCLUSIONS

LMWH showed to be at least as safe as UFH for ECC anticoagulation in chronic hemodialysis. The limited number of studies reporting on osteoporosis and HIT does not allow any conclusion for these outcomes. Larger studies are needed to evaluate properly the safety of LMWH in chronic hemodialysis.

Quantification and Dosing of Renal Replacement Therapy in Acute Kidney Injury: A Reappraisal

BACKGROUND/AIMS

Delivered dialysis therapy is routinely measured in the management of patients with end-stage renal disease; yet, the quantification of renal replacement prescription and delivery in acute kidney injury (AKI) is less established. While continuous renal replacement therapy (CRRT) is widely understood to have greater solute clearance capabilities relative to intermittent therapies, neither urea nor any other solute is specifically employed for CRRT dose assessments in clinical practice at present. Instead, the normalized effluent rate is the gold standard for CRRT dosing, although this parameter does not provide an accurate estimation of actual solute clearance for different modalities.

METHODS

Because this situation has created confusion among clinicians, we reappraise dose prescription and delivery for CRRT.

RESULTS

A critical review of RRT quantification in AKI is provided.

CONCLUSION

We propose an adaptation of a maintenance dialysis parameter (standard Kt/V) as a benchmark to supplement effluent-based dosing of CRRT. Video Journal Club "Cappuccino with Claudio Ronco" at http://www.karger.com/?doi=475457.

A magnetisation and Mössbauer study of triazole (M1−x2+Mx3+)M3+F5(Htaz)1−x(taz)x weberites (M = Fe, Co, Mn, Zn, Ga, V)

Several (M_1−x²⁺M_x³⁺)M³⁺F₅(Htaz)_1−x(taz)_x weberites, magnetically frustrated, exhibit negative magnetisations. ⁵⁷Fe Mössbauer spectrometry evidences a significant decrease of T_N for vacuum-treated samples.

Changes in Urinary and Serum Levels of Novel Biomarkers after Administration of Gadolinium-based Contrast Agents

OBJECTIVE

The aim of our study is to describe the changes in urinary and serum levels of novel biomarkers after gadolinium contrast administration in patients with normal renal function.

METHODS

We measured four biomarkers in 28 volunteers: interleukin-18 (IL-18), N-acetyl-glucosaminidase (NAG), neutrophil gelatinase-associated lipocalin, and cystatin C. Urinary and serum samples were collected at 0, 3, and 24 hours following gadolinium administration.

RESULTS

Baseline serum creatinine was 57.8 ± 34.5 µmol/L and remained stable. Urinary IL-18 levels increased significantly at three hours (10.7 vs. 7.3 ng/mg creatinine; P < 0.05). Similarly, urinary NAG levels increased significantly at three hours (3.9 vs. 2.2 IU/mg creatinine; P < 0.001). For both these markers, the difference was no longer significant at 24 hours. No statistically significant differences were observed for urinary and serum neutrophil gelatinase-associated lipocalin levels and for serum cystatin C levels.

CONCLUSIONS

Urinary IL-18 and NAG levels increased transiently after administration of gadolinium-based contrast agents in patients with normal renal function.

[Early-stage endometrial cancer: Sentinel node or lymphadenectomy?]

The endometrial cancers are mainly discovered at an early stage justifying a less aggressive treatment. The therapeutic choices are today based on preoperative classifications themselves based on histo-prognostic factors of the tumor and its extension measured in MRI: consequently, lymph node dissection in case of low and intermediate risk cancer is not systematically achieved. But a number of patients have lymph node involvement finally, probably justifying an adapted surgical and adjuvant treatment. The technique of sentinel node would compensate the weaknesses of preoperative prognostic evaluation. This new operative technique needs to be precised and evaluated: the topics subject to discussion are the technical implementation, the definition of its quality standards and the management of its histological results especially in cases of low volume lymph node metastasis.

Pharmacokinetics of an extended 4-hour infusion of piperacillin-tazobactam in critically ill patients undergoing continuous renal replacement therapy

STUDY OBJECTIVE

To evaluate the pharmacokinetic and pharmacodynamic profiles of piperacillin-tazobactam administered as a 4-hour infusion in critically ill patients undergoing continuous renal replacement therapy (CRRT).

DESIGN

Prospective, observational, pharmacokinetic study.

SETTING

Intensive care unit of a tertiary care hospital in Montréal, Canada.

PATIENTS

Twenty critically ill adults who were undergoing continuous venovenous hemodiafiltration and receiving a 4-hour infusion of piperacillin 4 g-tazobactam 0.5 g every 8 hours for a documented or suspected infection.

INTERVENTION

Blood samples were collected every hour over an 8-hour dosing interval. Prefilter and postfilter blood samples, and effluent and urine samples were also collected.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the proportion of patients who achieved an unbound piperacillin plasma concentration above a target minimum inhibitory concentration (MIC) of 64 mg/L (MIC that inhibits 90% of isolates for Pseudomonas aeruginosa) for at least 50% of the dosing interval; 18 (90%) of the 20 patients achieved this outcome. In all patients, the free piperacillin concentrations were above the Pseudomonas aeruginosa breakpoint of 16 mg/L for the entire time interval. Regarding piperacillin pharmacokinetic parameters, the median (interquartile range) minimum unbound plasma concentration was 65.15 mg/L (51.30-89.30), maximum unbound plasma concentration was 141.3 mg/L (116.75-173.90), sieving coefficient was 0.809 (0.738-0.938), total clearance was 65.82 ml/minute (53.79-102.87), and renal clearance was 0.16 ml/minute (0.05-3.04). The median CRRT dose was 32.0 ml/kg/h (25.0-39.8).

CONCLUSIONS

Administration of a 4-hour infusion of piperacillin-tazobactam was associated with a favorable pharmacodynamic profile in patients undergoing CRRT. Concentrations associated with maximal activity were attained in our patients.

Predictors of Transfer to Home Hemodialysis after Peritoneal Dialysis Completion

♦

BACKGROUND

The aim of the present study was to evaluate the predictors of transfer to home hemodialysis (HHD) after peritoneal dialysis (PD) completion. ♦

METHODS

All Australian and New Zealand patients treated with PD on day 90 after initiation of renal replacement therapy between 2000 and 2012 were included. Completion of PD was defined by death, transplantation, or hemodialysis (HD) for 180 days or more. Patients were categorized as "transferred to HHD" if they initiated HHD fewer than 180 days after PD had ended. Multivariable logistic regression was used to evaluate predictors of transfer to HHD in a restricted cohort experiencing PD technique failure; a competing-risks analysis was used in the unrestricted cohort. ♦

RESULTS

Of 10 710 incident PD patients, 3752 died, 1549 underwent transplantation, and 2915 transferred to HD, among whom 156 (5.4%) started HHD. The positive predictors of transfer to HHD in the restricted cohort were male sex [odds ratio (OR): 2.81], obesity (OR: 2.20), and PD therapy duration (OR: 1.10 per year). Negative predictors included age (OR: 0.95 per year), infectious cause of technique failure (OR: 0.48), underweight (OR: 0.50), kidney disease resulting from hypertension (OR: 0.38) or diabetes (OR: 0.32), race being Maori (OR: 0.65) or Aboriginal and Torres Strait Islander (OR: 0.30). Comparable results were obtained with a competing-risks model. ♦

CONCLUSIONS

Transfer to HHD after completion of PD is rare and predicted by patient characteristics at baseline and at the time of PD end. Transition to HHD should be considered more often in patients using PD, especially when they fulfill the identified characteristics.

An Incident Cohort Study Comparing Survival on Home Hemodialysis and Peritoneal Dialysis (Australia and New Zealand Dialysis and Transplantation Registry)

BACKGROUND AND OBJECTIVES

Home dialysis is often recognized as a first-choice therapy for patients initiating dialysis. However, studies comparing clinical outcomes between peritoneal dialysis and home hemodialysis have been very limited.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This Australia and New Zealand Dialysis and Transplantation Registry study assessed all Australian and New Zealand adult patients receiving home dialysis on day 90 after initiation of RRT between 2000 and 2012. The primary outcome was overall survival. The secondary outcomes were on-treatment survival, patient and technique survival, and death-censored technique survival. All results were adjusted with three prespecified models: multivariable Cox proportional hazards model (main model), propensity score quintile-stratified model, and propensity score-matched model.

RESULTS

The study included 10,710 patients on incident peritoneal dialysis and 706 patients on incident home hemodialysis. Treatment with home hemodialysis was associated with better patient survival than treatment with peritoneal dialysis (5-year survival: 85% versus 44%, respectively; log-rank P<0.001). Using multivariable Cox proportional hazards analysis, home hemodialysis was associated with superior patient survival (hazard ratio for overall death, 0.47; 95% confidence interval, 0.38 to 0.59) as well as better on-treatment survival (hazard ratio for on-treatment death, 0.34; 95% confidence interval, 0.26 to 0.45), composite patient and technique survival (hazard ratio for death or technique failure, 0.34; 95% confidence interval, 0.29 to 0.40), and death-censored technique survival (hazard ratio for technique failure, 0.34; 95% confidence interval, 0.28 to 0.41). Similar results were obtained with the propensity score models as well as sensitivity analyses using competing risks models and different definitions for technique failure and lag period after modality switch, during which events were attributed to the initial modality.

CONCLUSIONS

Home hemodialysis was associated with superior patient and technique survival compared with peritoneal dialysis.

Outcomes of integrated home dialysis care: a multi-centre, multi-national registry study

BACKGROUND

The 'integrated home dialysis' model involving initiation of peritoneal dialysis (PD) first followed by home haemodialysis (HHD) has previously been proposed as an optimal form of dialysis that maximizes the advantages of both modalities. While this model has great potential, its clinical outcomes, especially compared with direct HHD initiation, remain uncertain.

METHODS

All incident home dialysis patients from the Australia and New Zealand Dialysis and Transplant (ANZDATA) registry between 2000 and 2012 were included. Propensity score matching was performed to evaluate patients initially treated with PD followed by HHD ('PD + HHD'), PD without subsequent transition to HHD ('PD only') and HHD without subsequent transition to PD ('HHD only'). The composite primary outcome was death and home dialysis technique failure (defined as transfer to facility haemodialysis for 90 days). Groups were compared using a Cox proportional hazards model.

RESULTS

The 2:1 matched cohort included 84 patients in the 'PD + HHD' group, 168 patients in the 'HHD only' group and 168 patients in the 'PD only' group. Compared with the 'PD + HHD' group, death and home dialysis technique failure was similar for patients treated with 'HHD only' [hazard ratio (HR) 0.92, 95% confidence interval (CI) 0.52-1.62; P = 0.77] and higher for those treated with 'PD only' (HR 3.22, 95% CI 1.97-5.25; P < 0.001).

CONCLUSION

Patients treated with PD first followed by HHD had a risk of death and home dialysis technique failure that was comparable to those treated with HHD as the only home dialysis modality and inferior to those treated with PD as the only home dialysis modality. These results support the 'integrated home dialysis model' in patients who initiate dialysis with PD.

IgD heavy-chain deposition disease: detection by laser microdissection and mass spectrometry

Monoclonal Ig deposition disease (MIDD) is a rare complication of monoclonal gammopathy characterized by deposition of monoclonal Ig light chains and/or heavy chains along the glomerular and tubular basement membranes. Here, we describe a unique case of IgD deposition disease. IgD deposition is difficult to diagnose, because routine immunofluorescence does not detect IgD. A 77-year-old man presented with proteinuria and renal failure, and kidney biopsy analysis showed a nodular sclerosing GN with extensive focal global glomerulosclerosis, tubular atrophy, and interstitial fibrosis. Immunofluorescence was negative for Ig deposits, although electron microscopy showed deposits in the glomeruli and along tubular basement membranes. Laser microdissection of glomeruli and mass spectrometry of extracted peptides showed a large spectra number for IgD, and immunohistochemistry showed intense glomerular and tubular staining for IgD. Together, these findings are consistent with IgD deposition disease. Bone marrow biopsy analysis showed 5% plasma cells, which stained for IgD. The patient was treated with bortezomib and dexamethasone, which resulted in improvement of hematologic parameters but no improvement of renal function. The diagnosis of IgD deposition disease underscores the value of laser microdissection and mass spectrometry in further evaluating renal biopsies when routine assessment fails to reach an accurate diagnosis.

Nonleg venous thrombosis in critically ill adults: a nested prospective cohort study

IMPORTANCE

Critically ill patients are at risk of venous thrombosis, and therefore guidelines recommend daily thromboprophylaxis. Deep vein thrombosis (DVT) commonly occurs in the lower extremities but can occur in other sites including the head and neck, trunk, and upper extremities. The risk of nonleg deep venous thromboses (NLDVTs), predisposing factors, and the association between NLDVTs and pulmonary embolism (PE) or death are unclear.

OBJECTIVE

To describe the frequency, anatomical location, risk factors, management, and consequences of NLDVTs in a large cohort of medical-surgical critically ill adults.

DESIGN, SETTING, AND PARTICIPANTS

A nested prospective cohort study in the setting of secondary and tertiary care intensive care units (ICUs). The study population comprised 3746 patients, who were expected to remain in the ICU for at least 3 days and were enrolled in a randomized clinical trial of dalteparin vs standard heparin for thromboprophylaxis.

MAIN OUTCOMES AND MEASURES

The proportion of patients who had NLDVTs, the mean number per patient, and the anatomical location. We characterized NLDVTs as prevalent or incident (identified within 72 hours of ICU admission or thereafter) and whether they were catheter related or not. We used multivariable regression models to evaluate risk factors for NLDVT and to examine subsequent anticoagulant therapy, associated PE, and death. RESULTS Of 3746 trial patients, 84 (2.2%) developed 1 or more non-leg vein thromboses (superficial or deep, proximal or distal). Thromboses were more commonly incident (n = 75 [2.0%]) than prevalent (n = 9 [0.2%]) (P < .001) and more often deep (n = 67 [1.8%]) than superficial (n = 31 [0.8%]) (P < .001). Cancer was the only independent predictor of incident NLDVT (hazard ratio [HR], 2.22; 95% CI, 1.06-4.65). After adjusting for Acute Physiology and Chronic Health Evaluation (APACHE) II scores, personal or family history of venous thromboembolism, body mass index, vasopressor use, type of thromboprophylaxis, and presence of leg DVT, NLDVTs were associated with an increased risk of PE (HR, 11.83; 95% CI, 4.80-29.18). Nonleg DVTs were not associated with ICU mortality (HR, 1.09; 95% CI, 0.62-1.92) in a model adjusting for age, APACHE II, vasopressor use, mechanical ventilation, renal replacement therapy, and platelet count below 50 × 10(9)/L. CONCLUSIONS AND RELEVANCE Despite universal heparin thromboprophylaxis, nonleg thromboses are found in 2.2% of medical-surgical critically ill patients, primarily in deep veins and proximal veins. Patients who have a malignant condition may have a significantly higher risk of developing NLDVT, and patients with NLDVT, compared with those without, appeared to be at higher risk of PE but not higher risk of death.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00182143.

Comparison of oral and intravenous alfacalcidol in chronic hemodialysis patients

Background

Activated vitamin D is the mainstay of treatment for secondary hyperparathyroidism (SHPT) in chronic hemodialysis patients. However, the optimal route of administration is still debated. The aim of our study was to compare efficacy of oral vs intravenous (IV) administration of alfacalcidol in hemodialysis. A secondary objective was to determine the cost-effectiveness advantage of oral administration.

Methods

Eighty-eight chronic hemodialysis patients receiving IV alfacalcidol three times a week were included in the study. All were switched to the same dose of alfacalcidol given orally three times a week during the hemodialysis session. A budget impact analysis was performed.

Results

Mean patient age was 64 years old and 43% were males. The mean alfacalcidol dose administered was 2.1 μg three times a week. After three months, serum parathormone (PTH) levels decreased from 80 to 59 pmol/L (p = 0.001) and total serum calcium levels increased from 2.34 to 2.40 mmol/L (p = 0.002). After six months, total serum calcium levels were still significantly higher. Alfacalcidol dosage was significantly decreased during study period; the mean reduction was 0.44 μg per dose. Finally, oral administration was associated with an annual cost reduction of 197 678$CAN and an annual nursing time reduction of 25 days.

Conclusion

Our findings support that switching IV to oral administration of alfacalcidol during hemodialysis sessions may lead to a similar control of SHPT with lower doses of activated vitamin D. This is a good strategy for optimizing compliance and may allow a dose reduction because of a greater efficacy to suppress PTH. Oral administration also has significant cost-effectiveness advantages.

Monthly fluctuations of insomnia symptoms in a population-based sample

STUDY OBJECTIVES

To document the monthly changes in sleep/insomnia status over a 12-month period; to determine the optimal time intervals to reliably capture new incident cases and recurrent episodes of insomnia and the likelihood of its persistence over time.

DESIGN

Participants were 100 adults (mean age = 49.9 years; 66% women) randomly selected from a larger population-based sample enrolled in a longitudinal study of the natural history of insomnia. They completed 12 monthly telephone interviews assessing insomnia, use of sleep aids, stressful life events, and physical and mental health problems in the previous month. A total of 1,125 interviews of a potential 1,200 were completed. Based on data collected at each assessment, participants were classified into one of three subgroups: good sleepers, insomnia symptoms, and insomnia syndrome.

RESULTS

At baseline, 42 participants were classified as good sleepers, 34 met criteria for insomnia symptoms, and 24 for an insomnia syndrome. There were significant fluctuations of insomnia over time, with 66% of the participants changing sleep status at least once over the 12 monthly assessments (51.5% for good sleepers, 59.5% for insomnia syndrome, and 93.4% for insomnia symptoms). Changes of status were more frequent among individuals with insomnia symptoms at baseline (mean = 3.46, SD = 2.36) than among those initially classified as good sleepers (mean = 2.12, SD = 2.70). Among the subgroup with insomnia symptoms at baseline, 88.3% reported improved sleep (i.e., became good sleepers) at least once over the 12 monthly assessments compared to 27.7% whose sleep worsened (i.e., met criteria for an insomnia syndrome) during the same period. Among individuals classified as good sleepers at baseline, risks of developing insomnia symptoms and syndrome over the subsequent months were, respectively, 48.6% and 14.5%. Monthly assessment over an interval of 6 months was found most reliable to estimate incidence rates, while an interval of 3 months proved the most reliable for defining chronic insomnia.

CONCLUSIONS

Monthly assessment of insomnia and sleep patterns revealed significant variability over the course of a 12-month period. These findings highlight the importance for future epidemiological studies of conducting repeated assessment at shorter than the typical yearly interval in order to reliably capture the natural course of insomnia over time.

Effect of cinacalcet availability and formulary listing on parathyroidectomy rate trends

Background

Recent trends in parathyroidectomy rates are not known. Our objective was to investigate the trend in parathyroidectomy rates between 2001 and 2010, and to evaluate if the availability and reimbursement of cinacalcet modified that trend.

Methods

Using a provincial administrative database, we included all adult patients receiving chronic dialysis treatments between 2001 and 2010 (incident and prevalent) in a time series analysis. The effect of cinacalcet availability on parathyroidectomy bimonthly rates was modeled using an ARIMA intervention model using different cut-off dates: September 2004 (Health Canada cinacalcet approval), January 2005, June 2005, January 2006, June 2006 (date of cinacalcet provincial reimbursement), and January 2007.

Results

A total of 12 795 chronic dialysis patients (mean age 64 years, 39% female, 82% hemodialysis) were followed for a mean follow-up of 3.3 years. During follow-up, 267 parathyroidectomies were identified, translating to an average rate of 7.0 per 1000 person-years. The average parathyroidectomy rate before cinacalcet availability was 11.4 /1000 person-years, and 3.6 /1000 person-years after cinacalcet public formulary listing. Only January 2006 as an intervention date in the ARIMA model was associated with a change in parathyroidectomy rates (estimate: -5.58, p = 0.03). Other intervention dates were not associated with lower parathyroidectomy rates.

Conclusions

A reduction in rates of parathyroidectomy was found after January 2006, corresponding to cinacalcet availability. However, decreased rates may be due to other factors occurring simultaneously with cinacalcet introduction and further studies are needed to confirm these findings.

Magnitude of discordance between registry data and death certificate when evaluating leading causes of death in dialysis patients

Background

Discordance between dialysis registry and death certificate reported death has been demonstrated. Since cause of death is measured using registry data in dialysis patients and death certificate data in the general population, comparisons of cause of death proportions between dialysis patients and the general population may be biased. Our aim was to compare the proportion of deaths attributed to cardiovascular disease (CVD), malignancy, and infections between patients receiving dialysis and the general population using death certificates for both, and to quantify the magnitude of discrepancy between registry and death certificate estimates in dialysis patients.

Methods

A retrospective cohort study of 5858 patients initiating maintenance dialysis between 2001 and 2007 was conducted. Cause of death was obtained from both registry and death certificate data for dialysis patients, and from death certificate data for the general population.

Results

Compared to the general population, use of death certificate data in dialysis patients resulted in smaller differences in the proportion of deaths attributed to CVD or infection than that from the registry. In the general population, the proportion of deaths due to CVD is 29.3% for men and 28.2% for women, and the proportion of deaths due to infection is 3.3% for men and 3.6% for women. For men, the proportion of deaths in dialysis patients due to CVD using registry data is 41.5%, compared with a proportion of 32.1% using death certificate data. Similarly for women, the proportion of deaths due to CVD using registry data is 35.2% and that using death certificate data 24.3%. The proportion of deaths due to infection in dialysis patients follows the same pattern: for men, the proportion of deaths due to infection using registry data is 9.9% and that from death certificate data at 5.0%; while for women the proportions are 11.6% and 4.8%, respectively.

Conclusions

While absolute cause-specific mortality rates did differ, evaluation of causes of death using death certificate in dialysis patients in Quebec revealed that they do not have substantially different proportion of death due to CVD or infections than the general population. Infections appeared to be a frequent complication leading to death, suggesting that infections are an important target to consider for reducing mortality in dialysis populations.

A phase II multicenter trial of hyperCVAD MTX/Ara-C and rituximab in patients with previously untreated mantle cell lymphoma; SWOG 0213

BACKGROUND

Rituximab-hyper-CVAD alternating with rituximab-high-dose methotrexate and cytarabine is a commonly utilized regimen in the United States for mantle cell lymphoma (MCL) based on phase II single institutional data. To confirm the clinical efficacy of this regimen and determine its feasibility in a multicenter study that includes both academic and community-based practices, a phase II study of this regimen was conducted by SWOG.

PATIENTS AND METHODS

Forty-nine patients with advanced stage, previously untreated MCL were eligible. The median age was 57.4 years (35-69.8 years).

RESULTS

Nineteen patients (39%) did not complete the full scheduled course of treatment due to toxicity. There was one treatment-related death and two cases of secondary myelodysplastic syndrome (MDS). There were 10 episodes of grade 3 febrile neutropenia, 19 episodes of grade 3 and 1 episode of grade 4 infection. With a median follow-up of 4.8 years, the median progression-free survival was 4.8 years (5.5 years for those ≤ 65 years) and the median overall survival (OS) was 6.8 years.

CONCLUSIONS

Although this regimen is toxic, it is active for patients ≤ 65 years of age and can be given both at academic centers and in experienced community centers.

Arteriovenous fistula for the 80 years and older patients on hemodialysis: is it worth it?

Over the last years, the proportion of patients older than 80 years with end-stage renal disease has been constantly growing. Arteriovenous fistula (AVF) is known as the best vascular access for hemodialysis, but evidence for its added value is lacking for elderly. We retrospectively identified new vascular access (AVF and central venous catheter) created or installed between June 2005 and June 2008 in patients 80 years and older and in patients between 50 and 60 years. For every new AVF, we calculated primary failure, primary and secondary patency durations. Fifty-five and 57 patients had a new vascular access in the >80 years old and 50 to 60 years old groups. Among these, 25 and 41 were new AVF in the older and younger groups. Primary failure was more frequent in elderly than in the younger (40% vs. 17%, P=0.04). Primary patency was not significantly different in both groups (P=0.06). Secondary patency was shorter in elderly (P=0.005). Among the older group, the presence of an AVF was not associated with a difference in mortality (46% vs. 60%, P=0.28), whereas there was a lower mortality in the younger group with AVF (12% vs. 43% P=0.008). These results indicate lower patency duration in very elderly patients compared to middle-aged patients. Without leading to the exclusion of patients over 80 years old for AVF creation, it might reinforce the need of a careful selection and evaluation in this population prior to referral.

Bevacizumab in combination with FOLFIRI chemotherapy in patients with metastatic colorectal cancer: an assessment of safety and efficacy in the province of Newfoundland and Labrador

BACKGROUND

In 2005, bevacizumab was approved by Health Canada for patients with metastatic colorectal cancer (mCRC). Newfoundland and Labrador was one of the first Canadian provinces to fund this agent in combination with FOLFIRI (irinotecan, 5-fluorouracil, leucovorin) chemotherapy. In this analysis, the entire provincial bevacizumab sample for the first 2 years was assessed for overall safety and efficacy.

METHODS

The medical records of 43 patients with mCRC who had received FOLFIRI with bevacizumab were identified and reviewed. The longitudinal data collection format that was adopted assessed occurrences of adverse events after each cycle of treatment. Toxicity outcomes such as gastrointestinal (GI) perforations, bleeding, diarrhea, myelosuppression, proteinuria, and venous thromboembolic events (VTEs) were collected and graded using the U.S. National Cancer Institute's Common Terminology Criteria for Adverse Events, version 3.0. Time to treatment failure (TTF) and overall survival (OS) were determined using the Kaplan-Meier method.

RESULTS

Overall, the 43 study patients received 398 cycles of anticancer therapy (median: 6 cycles; range: 1-24 cycles). No gi perforations were identified. However, 4 bleeding events occurred (9.3%), 3 requiring permanent discontinuation of bevacizumab. Also, 6 grade 3 or 4 VTEs occurred (14.0%), 3 of which required a hospital admission. In addition, grades 3 and 4 diarrhea, febrile neutropenia, and proteinuria showed cumulative incidences of 11.6%, 2.3%, and 2.3% respectively. Median TTF was 6.3 months; median os was 24.4 months.

CONCLUSIONS

Bevacizumab in combination with FOLFIRI appears to be well tolerated, and efficacy is consistent with trial reports. However, patients should be closely monitored to avoid potentially serious events such as bleeding and VTEs.