Steven D Soroka

Dalhousie University, Halifax, Nova Scotia, Canada

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Publications (34)91.17 Total impact

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    ABSTRACT: The relative influence of facilities and regions on the timing of dialysis initiation remains unknown. The purpose of the study is to determine the variation in eGFR at dialysis initiation across dialysis facilities and geographic regions in Canada after accounting for patient-level factors (case mix).
    Clinical journal of the American Society of Nephrology : CJASN. 09/2014;
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    ABSTRACT: Background: Physicians' perceptions and opinions may influence when to initiate dialysis. Objective: To examine providers' perspectives and opinions regarding the timing of dialysis initiation.
    The Canadian Journal of Kidney Health and Disease. 05/2014;
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    ABSTRACT: Dabigatran etexilate represents a possible improved alternative to warfarin for anticoagulation in hemodialysis patients with atrial fibrillation (AF). The objective was to determine dabigatran plasma concentrations and anticoagulant effects following administration of a single 110 mg oral dose of dabigatran etexilate to 10 adult patients immediately prior to starting hemodialysis. Mass spectrometry and the Hemoclot® assay were used, respectively, to determine free (unconjugated) dabigatran concentrations and thrombin time (TT) in plasma samples collected intermittently over 48 hours. The median time (tmax) to reach the maximum plasma free dabigatran concentration (Cmax) was 2 h (range 1–3 h). The mean free dabigatran Cmax was 95.5 ± 33.4 ng mL-1. The mean elimination half-lives on and off hemodialysis were, respectively 2.6 ± 1.3 h and 30.2 ± 7.8 h. Hemodialysis effectively removed dabigatran with an extraction ratio of 0.63 ± 0.07. The maximal TT ratio was 2.1 and the TT ratio demonstrated a strong linear dependence on free dabigatran concentration (r2 = 0.741). A 110 mg oral dabigatran dose prior to hemodialysis was rapidly absorbed and achieved therapeutic concentrations. Hemodialysis effectively removed dabigatran from the plasma and may be an effective means of accelerating the elimination of dabigatran in circumstances of excessive anticoagulation.
    The Journal of Clinical Pharmacology 05/2014; · 2.84 Impact Factor
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    ABSTRACT: Usually inaugural editorials are written by the Editor-in-Chief to describe the scope and vision for the journal to potential authors and readers. This editorial is written by the Editor-in-Chief, the Deputy Editors and the Associate Editors collaboratively as a clear signal that this is a unique and different journal. We will build this journal on a set of principles which are fundamental to improving the outcomes of patients with kidney disease. To that end, we aim to be supportive, to collaborate, to integrate multiple perspectives and to be open to possibilities. Résumé
    The Canadian Journal of Kidney Health and Disease. 04/2014;
  • Canadian Journal of Kidney Health and Disease. 01/2014; 1(1):3.
  • Canadian Journal of Kidney Health and Disease. 01/2014; 1(1):2.
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    ABSTRACT: Peritoneal dialysis is associated with similar survival and similar improvement in quality of life and is less costly compared with in-centre hemodialysis. We examined facility and geographic variation in the use of peritoneal dialysis in Canada.
    CMAJ open. 01/2014; 2(1):E36-44.
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    ABSTRACT: The KDIGO (Kidney Disease: Improving Global Outcomes) 2012 clinical practice guideline for anemia management in patients with chronic kidney disease provides the structural and evidence base for the Canadian Society of Nephrology commentary on this guideline's relevancy and application to the Canadian health care system. While in general agreement, we provide commentary on 11 of the 61 KDIGO guideline statements. Specifically, we agreed that a therapeutic trial of iron is appropriate in cases in which a reduction in erythropoiesis-stimulating agent (ESA) dosage or avoidance of ESA and transfusion is desired, transferrin saturations are >30%, and ferritin concentrations are >500 μg/L. However, we concluded that there is insufficient evidence to support an upper target or threshold for ferritin and transferrin saturation levels. We agree with the initiation of ESA treatment when hemoglobin (Hb) level is 90-100 g/L; however, we specifically state that an acceptable range for Hb level is 95-115 g/L, with a target of 100-110 g/L, and add caution to individualization above this range due to concerns regarding the safety of ESAs. We agree that ESAs should be used with considerable caution in patients with active malignancy, history of stroke, or history of malignancy, and we suggest initiating ESA therapy at Hb level of 90 g/L and to aim for a Hb level in the range of 90-105 g/L. The reader is encouraged to note the level of evidence and review the entire KDIGO anemia guideline to interpret the guideline statements and commentary appropriately.
    American Journal of Kidney Diseases 09/2013; · 5.29 Impact Factor
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    ABSTRACT: The prevalence of chronic kidney disease (CKD) increases with age, and the risk of significant anaemia increases as renal function declines. The objectives of this study were to assess the effect of darbepoetin alfa administration on health-related quality of life (HRQOL) through treatment for anaemia in older patients with CKD. In this multicentre, randomised, placebo-controlled trial, older patients (aged ≥70 years) with CKD (Stages 3-5, predialysis) and haemoglobin (Hb) < 11.0 g/dL were randomised to darbepoetin alfa (n = 28) or placebo (n = 23). HRQOL was measured using a number of instruments including Short Form-36 (SF-36) and Functional Assessment of Cancer Therapy-Anaemia (FACT-An). The primary endpoint, mean SF-36 Vitality Score at Week 24, was comparable between the darbepoetin alfa (51.4 [95 % CI 48.0, 54.9]) and placebo (46.7 [40.9, 52.5]) groups. Darbepoetin alfa-treated patients experienced statistically significant improvements in some SF-36 and FACT-An Subscale Scores. Mean Hb was higher with darbepoetin alfa (12.5 [12.1, 12.9] g/dL) than with placebo (10.5 [10.1, 11.0] g/dL). The safety profiles were comparable between the treatment groups. The study was limited by only 20 % of the planned patient recruitment being achieved. Darbepoetin alfa increased Hb and, within study limitations, suggested that improvements in some HRQOL domains in older CKD patients with anaemia may be achieved with more physiological haemoglobin.
    International Urology and Nephrology 08/2013; · 1.33 Impact Factor
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    ABSTRACT: Background: Calcific uremic arteriolopathy (CUA) is a rare but serious disorder affecting 4% of dialysis patients. Intravenous sodium thiosulfate (IV STS) has been shown as an effective treatment. In Canada, the average cost of IV STS is about CAD 12,000 per month, while the cost of compounded oral STS is CAD 45 per month. Methods: Prospective cohort where all patients diagnosed with CUA during the year 2011 were included. They were treated initially with IV STS. Afterwards, each patient had a baseline bone scan and was started on oral STS for a total of 6 months followed by a repeat bone scan. A single radiologist, blinded to the dates of both scans for a given patient, read all scans. Results: Four patients were studied. The intravenous dose used was 25 g three times a week for an average duration of 131 days. After the maintenance therapy, 2 patients developed further regression of the lesions, 1 had stable lesions, and 1 got worse; however, nonadherence to the drug was confirmed. The oral medication was well tolerated with no reported side effects. Conclusion: Oral STS, after IV STS, seems to stabilize, or even improve CUA lesions, and therefore could be useful as maintenance therapy, especially since its cost is much more reasonable than IV STS and due to the ongoing shortage of the IV formulation.
    American Journal of Nephrology 01/2013; 37(2):104-109. · 2.62 Impact Factor
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    ABSTRACT: Background: The use of central venous catheters (CVC) in hemodialysis has been growing, thereby more infections and thromboses are encountered on daily basis. Certain enhancements have been applied to the CVCs to minimize these complications, however, these come at a cost. Using Enhanced CVCs would be cost effective if they require less fibrinolysis and have longer patency. Methods: A randomized controlled trial comparing the Enhanced, heparin and silver coated (Sapphire Palindrome) to Standard CVCs (Hemostar), with the hypothesis that using Enhanced CVCs will result in decreased tPA use and prolonged catheter patency. Those with new CVC incretion or replacement, using 19 or 23 cm placed over the right or left IJ were included. The primary outcome was the difference in tPA use. The secondary outcomes were the time to the first tPA use, and the times to CVC replacement for poor flow or bacteremia. Results: 61 Enhanced and 58 Standard CVCs in 92 patients were included in the final analysis. Patients characteristics were the same. The mean tPA doses were 15.6 mg and 17.1 mg for the Enhanced and Standard groups, respectively (P=0.59). The cumulative time to first tPA use was 162 (95% CI 116 to 209) and 156 (95% CI 113 to 200) days for both groups respectively (P=0.54).12 Enhanced and 8 Standard CVCs were changed due to poor flow, respectively (P=0.47), also 7 and 11 were changed due bacteremia, respectively (P=0.31). There were no differences on cumulative time to CVC removal due to poor flow or bacteremia. More cuff migrations were seen in the Enhanced group. Conclusions: Using heparin and silver coated CVCs does not seem to be cost effective, as there was no difference in catheter survival. Given the small numbers of bacteremia, significant difference might have been missed.
    ASN Kidney Week, San Diego, CA, USA; 11/2012
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    ABSTRACT: Central venous catheters (CVCs) are associated with early mortality in dialysis patients. However, some patients progress to end stage renal disease after an acute illness, prior to reaching an estimated glomerular filtration rate (eGFR) at which one would expect to establish alternative access (fistula/peritoneal dialysis catheter). The purpose of this study was to determine if exclusion of this "acute start" patient group alters the association between CVCs and mortality. We conducted a retrospective cohort study of 406 incident dialysis patients from 1 Jan 2006 to 31 Dec 2009. Patients were classified as acute starts if 1) the eGFR was >25 ml/min/1.73 m2, ≤3 months prior to dialysis initiation and declined after an acute event (n = 45), or 2) in those without prior eGFR measurements, there was no supporting evidence of chronic kidney disease on history or imaging (n = 12). Remaining patients were classified as chronic start (n = 349). 98 % and 52 % of acute and chronic starts initiated dialysis with a CVC. There were 148 deaths. The adjusted mortality hazard ratio (HR) for acute vs. chronic start patients was 1.84, (95 % CI [1.19-2.85]). The adjusted mortality HR for patients dialyzing with a CVC compared to alternative access was 1.19 (95 % CI [0.80-1.77]). After excluding acute start patients, the adjusted HR fell to 1.03 (95 % CI [0.67-1.57]). A significant proportion of early dialysis mortality occurs after an acute start. Exclusion of this population attenuates the mortality risk associated with CVCs.
    BMC Nephrology 07/2012; 13:72. · 1.64 Impact Factor
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    ABSTRACT: Hyperphosphatemia is a common and potentially harmful condition in patients with end-stage kidney disease. In Canada, first-line treatment of hyperphosphatemia consists primarily of calcium carbonate (CC). Lanthanum carbonate (LC) and sevelamer hydrochloride (SH) are non-calcium phosphate binders that have been used as second-line therapy in patients intolerant of or not responsive to CC. The primary objective of the present study was to assess the costs and clinical benefits of second-line use of LC after therapy failure with CC in patients receiving dialysis, from a Canadian payer perspective. The secondary objective was to perform an economic comparison between second-line LC therapy and second-line SH therapy, from a Canadian payer perspective. Short-term outcomes were treatment response and cost per additional responder, and long-term outcomes were survival, number of all-cause hospitalizations, and quality of life. A cost-effectiveness Markov model was populated with simulated cohorts of 1000 patients receiving incident dialysis, followed life-long. Patients not responsive to CC with a serum phosphate concentration >1.78 mmol/L (>5.5 mg/dL) received a trial regimen with LC. Patients not responsive to LC returned to CC therapy. Patient data from a randomized controlled trial of 800 patients receiving dialysis were used. Extensive (probabilistic) sensitivity analyses were performed. When available, model parameters were based on Canadian data or from a Canadian perspective. All costs are in 2010 Canadian dollars (C$). Results of the model estimated that in patients responsive to second-line LC therapy, survival increased, on average, 0.44 years (95% confidence interval [CI], 0.35-0.54) per patient when compared with continued CC therapy. The mean (range) costs per patient in the first year of treatment with LC was C$2600 (C$2400-C$2800). Over patients' lifetimes, the second-line LC strategy resulted in a gain of 48.8 (37.1-61.3) life-years and 29.3 (21.4-38.1) quality-adjusted life-years (QALYs). The cost-effectiveness of the second-line LC strategy was C$7900 (C$1800-C$14,600) per life-year and C$13,200 (C$3000-C$25,100) per QALY gained. Most sensitivity analyses did not change the cost-effectiveness outcomes; however, including unrelated future costs raised the incremental cost-effectiveness ratio to C$159,500 (95% confidence interval, C$133,300-C$191,600) per QALY gained. Compared with second-line SH therapy, second-line LC therapy had similar effectiveness and was 23% less expensive. Second-line treatment with LC is cost-effective in the treatment of end-stage kidney disease in patients with hyperphosphatemia, from a Canadian payer perspective. Second-line treatment with LC is less expensive, with similar effectiveness as second-line treatment with SH. The primary limitation of health economic evaluations of phosphate binders is the relative scarcity of clinical data on the association between phosphate concentration and long-term outcome.
    Clinical Therapeutics 06/2012; 34(7):1531-43. · 2.23 Impact Factor
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    ABSTRACT: BACKGROUND: There is a concern that some, especially older people, are not referred and could benefit from transplantation. METHODS: We retrospectively examined consecutive incident end stage renal disease (ESRD) patients at our center from January 2006 to December 2009. At ESRD start, patients were classified into those with or without contraindications using Canadian eligibility criteria. Based on referral for transplantation, patients were grouped as CANDIDATE (no contraindication and referred), NEITHER (no contraindication and not referred) and CONTRAINDICATION. The Charlson Comorbidity Index (CCI) was used to assess comorbidity burden. RESULTS: Of the 437 patients, 133 (30.4%) were CANDIDATE (mean age 50 and CCI 3.0), 59 (13.5%) were NEITHER (age 76 and CCI 4.4), and 245 (56.1%) were CONTRAINDICATION (age 65 and CCI 5.5). Age was the best discriminator between NEITHER and CANDIDATES (c-statistic 0.96, P <0.0001) with CCI being less discriminative (0.692, P <0.001). CANDIDATES had excellent survival whereas those patients designated NEITHER and CONTRAINDICATION had high mortality rates. NEITHER patients died or developed a contraindication at very high rates. By 1.5 years 50% of the NEITHER patients were no longer eligible for a transplant. CONCLUSIONS: There exists a relatively small population of incident patients not referred who have no contraindications. These are older patients with significant comorbidity who have a small window of opportunity for kidney transplantation.
    Transplantation research. 01/2012; 1(1):22.
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    ABSTRACT: It is unclear how to optimally care for chronic kidney disease (CKD). This study compares a new coordinated model to usual care for CKD. A randomized trial in nephrology clinics and the community included 474 patients with median estimated GFR (eGFR) 42 ml/min per 1.73 m(2) identified by laboratory-based case finding compared care coordinated by a general practitioner (controls) with care by a nurse-coordinated team including a nephrologist (intervention) for a median (interquartile range [IQR]) of 742 days. 32% were diabetic, 60% had cardiovascular disease, and proteinuria was minimal. Guided by protocols, the intervention team targeted risk factors for adverse kidney and cardiovascular outcomes. Serial eGFR and clinical events were tracked. The average decline in eGFR over 20 months was -1.9 ml/min per 1.73 m(2). eGFR declined by ≥4 ml/min per 1.73 m(2) within 20 months in 28 (17%) intervention patients versus 23 (13.9%) control patients. Control of BP, LDL, and diabetes were comparable across groups. In the intervention group there was a trend to greater use of renin-angiotensin blockers and more use of statins in those with initial LDL >2.5 mmol/L. Treatment was rarely required for anemia, acidosis, or disordered mineral metabolism. Clinical events occurred in 5.2% per year. Patients with stage 3/4 CKD identified through community laboratories largely had nonprogressive kidney disease but had cardiovascular risk. Over a median of 24 months, the nurse-coordinated team did not affect rate of GFR decline or control of most risk factors compared with usual care.
    Clinical Journal of the American Society of Nephrology 06/2011; 6(6):1241-7. · 5.07 Impact Factor
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    ABSTRACT: Potential cost and effectiveness of a nephrologist/nurse-based multifaceted intervention for stage 3 to 4 chronic kidney disease are not known. This study examines the cost-effectiveness of a chronic disease management model for chronic kidney disease. Cost and cost-effectiveness were prospectively gathered alongside a multicenter trial. The Canadian Prevention of Renal and Cardiovascular Endpoints Trial (CanPREVENT) randomized 236 patients to receive usual care (controls) and another 238 patients to multifaceted nurse/nephrologist-supported care that targeted factors associated with development of kidney and cardiovascular disease (intervention). Cost and outcomes over 2 years were examined to determine the incremental cost-effectiveness of the intervention. Base-case analysis included disease-related costs, and sensitivity analysis included all costs. Consideration of all costs produced statistically significant differences. A lower number of days in hospital explained most of the cost difference. For both base-case and sensitivity analyses with all costs included, the intervention group required fewer resources and had higher quality of life. The direction of the results was unchanged to inclusion of various types of costs, consideration of payer or societal perspective, changes to the discount rate, and levels of GFR. The nephrologist/nurse-based multifaceted intervention represents good value for money because it reduces costs without reducing quality of life for patients with chronic kidney disease.
    Clinical Journal of the American Society of Nephrology 06/2011; 6(6):1248-57. · 5.07 Impact Factor
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    ABSTRACT: To determine whether warfarin prolongs the time to first mechanical-catheter failure. This was a multicenter parallel-group randomized controlled trial with blinding of participants, trial staff, clinical staff, outcome assessors, and data analysts. Randomization was in a 1:1 ratio in blocks of four and was concealed by use of fax to a central pharmacy. Hemodialysis patients with newly-placed catheters received low-intensity monitored-dose warfarin, target international normalized ratio (INR) 1.5 to 1.9, or placebo, adjusted according to schedule of sham INR results. The primary outcome was time to first mechanical-catheter failure (inability to establish a circuit or blood flow less than 200 ml/min). We randomized 174 patients: 87 to warfarin and 87 to placebo. Warfarin was associated with a hazard ratio (HR) of 0.90 (P=0.60; 95% confidence interval [CI], 0.57, 1.38) for time to first mechanical-catheter failure. Secondary analyses were: time to first guidewire exchange or catheter removal for mechanical failure (HR 0.78; 95% CI, 0.37, 1.6); time to catheter removal for mechanical failure (HR 0.67; 95% CI, 0.19, 2.37); and time to catheter removal for any cause (HR 0.89; 95% CI, 0.42, 1.81). Major bleeding occurred in 10 participants assigned to warfarin and seven on placebo (relative risk, 1.43; 95% CI, 0.57, 3.58; P=0.61). We found no evidence for efficacy of low-intensity, monitored-dose warfarin in preventing mechanical-catheter failure.
    Clinical Journal of the American Society of Nephrology 05/2011; 6(5):1018-24. · 5.07 Impact Factor
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    ABSTRACT: Abnormal mineral metabolism is associated with increased morbidity and mortality in dialysis patients. Therefore, the goal of this study was to compare a) mineral metabolism control among a cohort of Canadian peritoneal dialysis (PD) patients to K/DOQI-defined targets and b) the effect of different treatment strategies on mineral metabolism parameters. We looked at a cohort of 317 Canadian PD patients from 9 clinics that used the PhotoGraph™ software program which tracks mineral metabolism management. Serum phosphorus (P), calcium (Ca) and intact parathyroid hormone (iPTH) values were collected for the patients. Data were categorized and analyzed by the type of phosphate binder prescribed, vitamin D use, and dosing and reimbursement criteria for the phosphate binder, sevelamer. The majority of patients achieved K/DOQI-set targets for serum P. Patients who resided in Quebec (QC), which had greater access to sevelamer, had lower mean concentrations of P and Ca, were less likely to take Ca-based phosphate binders (CBBs) exclusively and were exposed to less exogenous Ca than in Ontario (ON). Availability of the phosphate binder sevelamer and reduced doses of elemental Ca were associated with more mineral metabolism parameters within suggested target ranges. Further studies that focus on patient outcomes are warranted.
    Clinical nephrology 05/2011; 75(5):410-5. · 1.29 Impact Factor
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    ABSTRACT: Abnormalities in mineral metabolism in chronic kidney disease are associated with increased morbidity and mortality. The Kidney Disease Outcomes Quality Initiative (K/DOQI) clinical practice guidelines were established in 2003 to address issues in the management of mineral and bone metabolism. The goal of this study was to compare (i) mineral metabolism control among Canadian haemodialysis (HD) patients with K/DOQI-defined targets and Dialysis Outcomes and Practice Patterns Study II (DOPPS II) data and (ii) the effect of different treatment strategies. A cross-sectional study of 2215 HD patients was conducted. Phosphorus (P), calcium (Ca), intact parathyroid hormone (iPTH) and calcium-phosphate product (CaXP) were analysed. In addition, management was compared between provinces with more or less restricted access to the phosphate binder sevelamer. K/DOQI targets for P, Ca, iPTH and CaXP K/DOQI targets were met by 59.7%, 58.6%, 29.7% and 83.3%, respectively. A greater proportion of patients were within target compared with those in DOPPS II (2002-2004). Targets were more likely to be reached by patients residing in provinces with formularies allowing less restricted access to sevelamer: P: 61.8% vs 55.7% (P = 0.01); CaXP: 85.5% vs 79.1% (P = 0.0006). As expected, patients in provinces with more restrictive formularies were more often receiving doses of elemental calcium > 1.5 g/day than those with more open listings (62.1% vs 14.0%, P < 0.0001) and were less likely to receive sevelamer (14.1% vs 42.4%, P = 0.0001). Mineral metabolism parameters were more frequently within the target range amongst (i) patients in the current study compared with those in the DOPPS II era and (ii) patients in provinces with less restricted access to sevelamer.
    Nephrology Dialysis Transplantation 01/2011; 26(1):156-63. · 3.37 Impact Factor
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    ABSTRACT: Macrocytosis occurs in chronic hemodialysis (CHD) patients; however, its significance is unknown. The purpose of this study was to establish the prevalence and distribution of macrocytosis, to identify its clinical associations and to determine if macrocytosis is associated with mortality in stable, chronic hemodialysis patients. We conducted a single-centre prospective cohort study of 150 stable, adult CHD patients followed for nine months. Macrocytosis was defined as a mean corpuscular volume (MCV) > 97 fl. We analyzed MCV as a continuous variable, in tertiles and using a cutoff point of 102 fl. The mean MCV was 99.1 ± 6.4 fl, (range 66-120 fl). MCV was normally distributed. 92 (61%) of patients had an MCV > 97 fl and 45 (30%) > 102 fl. Patients were not B12 or folate deficient in those with available data and three patients with an MCV > 102 fl had hypothyroidism. In a logistic regression analysis, an MCV > 102 fl was associated with a higher Charlson-Age Comorbidity Index (CACI) and higher ratios of darbepoetin alfa to hemoglobin (Hb), [(weekly darbepoetin alfa dose in micrograms per kg body weight / Hb in g/L)*1000]. There were 23 deaths at nine months in this study. Unadjusted MCV > 102 fl was associated with mortality (HR 3.24, 95% CI 1.42-7.39, P = 0.005). Adjusting for the CACI, an MCV > 102 fl was still associated with mortality (HR 2.47, 95% CI 1.07-5.71, P = 0.035). Macrocytosis may be associated with mortality in stable, chronic hemodialysis patients. Future studies will need to be conducted to confirm this finding.
    BMC Nephrology 01/2011; 12(1):19. · 1.64 Impact Factor