O R I G I N A L P A P E R

Blood Volume Measurements in Patients With Heart Failure and aPreserved Ejection Fraction: Implications for Diagnosing Anemia

A nemia is common in patients withheart failure (HF), associated

with increased morbidity including hos-pitalizations, mortality, and a reducedquality of life.1 These associations arepresent in HF, regardless of left ventricu-lar ejection fraction (LVEF).2,3 Thesedata have led to several randomizedclinical trials using erythropoietin-stimulating agents,4,5 iron,6 and theircombination,7,8 predominately inpatients with systolic HF to determinesafety and efficacy. These trials havedemonstrated reduction in hospitali-zations and improvement in functionalcapacity and ventricular function butare limited by their small sample sizeand short duration.9

The diagnosis of anemia is usuallymade by measurement of hemoglobinvalues from standard peripheral blood;however, in patients with volume over-load states such as systolic HF, hemodi-lution has been shown to be a commoncause of low hemoglobin10 and has beensuggested to be the most potent factorfor the low hemoglobin values observedin patients with HF and a reduced ejec-tion fraction.11

Such data raise concerns that formany patients with systolic HF, treatinganemia with agents to stimulate red cellproduction may not be justified. Addi-tionally, alterations in plasma volume(PV) occur as a compensation for thecontracted red blood cell volume(RBCV) in order to maintain the over-all blood volume (BV) at a constantlevel12 and could also confoundthe diagnosis of anemia. Finally, thelong-term use of medications such asdiuretics, that act by contracting PV,could result in an underdiagnosis ofanemia based on standard hemoglobinmeasures.

In the general population13,14 andamong patients with HF either in thesetting of a reduced or normal ⁄preservedejection fraction,2 the prevalence ofanemia is higher among blacks thanwhites. Despite the fact that Hispanicsare the largest and fastest-growing eth-nic minority in the United States,15 dataon the prevalence of anemia in thiscohort compared with other racialgroups in patients with HF are lacking.We hypothesized that analysis of BV inpatients with HFPEF could provideinsights into racial differences amongpersons affected by this heterogeneousclinical syndrome.

MethodsStudy Patients. Participants were out-patients referred for evaluation andtreatment to the Columbia UniversityMedical Center Heart Failure Center.Patients 21 years and older diagnosedwith HF and a preserved ejection frac-tion (eg,�45%) were studied.

The diagnosis of HF was based on theNational Health and Nutrition Exami-nation Survey congestive HF criteriawith a score �3.16 Patients with acutedecompensated HF, severe renal dys-function (serum creatinine >3.0 mg ⁄dLor history of nephrotic syndrome), andsevere hepatic dysfunction (serum liver

Racial differences in the prevalence of anemia in patients with heart failure have beennoted. The diagnosis of anemia in heart failure patients can be confounded by manyfactors. Plasma volume expansion is one of the most prominent confounders. The authorsinvestigated the difference of anemia prevalence using two different diagnostictechniques: peripheral hemoglobin recommended by the World Health Organizationcriteria and blood volume (BV) analysis. Racial disparities in the prevalence of anemiausing both measures were compared. Sixty patients with heart failure and preservedejection fraction (HFPEF) underwent measurement of BV by a radio-labeled albumintechnique. Anemia was defined by both WHO criteria and by measured red blood cellvolume (RBCV)>10% below ideal. Anemia was found in 67% of patients by theperipheral hemoglobin technique with no racial disparity. Only 35% of the patients hadanemia by the BV analysis, with a 2-fold higher prevalence among Hispanics comparedwith whites and blacks. In patients with HFPEF, the diagnosis of anemia based onhemoglobin is confounded by plasma volume derangements resulting in significantoverdiagnosis in this cohort. Racial differences in the rate of anemia were found. Suchdata could have important implications for the diagnosis and management of anemia inethnic minorities with HFPEF. Congest Heart Fail. 2011;17:14–18. �2011 WileyPeriodicals, Inc.

Bassel Noumi, MD; Sergio Teruya, MD; Say Salomon, MD;Stephen Helmke, RDCS, MPH; Mathew S. Maurer, MDFrom the Columbia University Medical Center, New York, NY

Address for correspondence:Mathew S. Maurer, MD, Clinical Cardiovascular Research Laboratory for theElderly, Columbia University Medical Center, Allen Hospital of New YorkPresbyterian, 5141 Broadway, 3 Field West, Room 035, New York, NY 10034E-mail: msm10@columbia.eduManuscript received December 20, 2010; accepted December 30, 2010

doi: 10.1111/j.1751-7133.2010.00208.x

blood volume measurements in patients with HEPEF january • february 201114

enzymes >3 times the upper limits ofnormal or history of cirrhosis) wereexcluded. Cardiac medications includeddiuretics, digoxin, renin-angiotensin sys-tem inhibitors, and ⁄or b-adrenergicreceptor antagonists that were stablebefore the measurement of BV. Sixtyambulatory patients with HFPEF werestudied: 33% white, 40% Hispanic, and27% black. The institutional reviewboard at Columbia University MedicalCenter approved the protocol. Allpatients gave written informed consentbefore participation.

Hemoglobin Measures. Hemoglobinwas measured as part of a routine com-plete blood cell count from the hospitalcore laboratory (Sysmex XE 2100; Sys-mex Corporation, Kobe, Japan). Ane-mia was defined according to WorldHealth Organization (WHO) criteria as

hemoglobin <12 g ⁄dL in women and<13 g ⁄dL in men.17

BV Analysis. PV was determined afterthe intravenous administration ofiodine-131–labeled albumin, as has beendescribed previously.18,19 BV and RBCVwere calculated from the PV measure-ment, the measured hematocrit cor-rected for trapped plasma, and meanbody hematocrit. BV components(plasma, red blood cell, and total vol-ume) were determined and comparedwith normal values adjusted for age, sex,and weight on the basis of the idealweight system to yield percentage devia-tions from normal. Thus, in addition toreporting absolute values, we report per-centage deviation from expected valueson the basis of the ideal weight system.Anemia, based on BV analysis, wasdefined by RBCV <10% below ideal.

To determine whether PV compensa-tion in patients with RBCV deficits wasappropriate, the absolute PV compensa-tion in response to RBCV deficit wascalculated as deviation from ideal PV –RBCV deficit, and the percentage com-pensation was calculated as (deviationfrom ideal PV – RBCV deficit) ⁄ idealPV.

Statistical Analysis. Data are expressedas mean � standard deviation, unlessotherwise noted. Dichotomous variableswere compared using chi-square analysiswith Fisher exact test when appropriate,and continuous variables were comparedusing analysis of variance with a Bonfer-roni’s post hoc test to control for multi-ple comparisons for those variables thatwere normally distributed. For the BVdata, a nonparametric test (KruskalWallis) was employed given the

Table I. Demographic and Clinical Characteristics

OVERALL (N=60) WHITES (N=20) BLACKS (N=16) HISPANICS (N=24) P VALUE

DemographicsAge, y 70�12.9 75�13 68�15 67�11 NSSex (female), % 63 40 81 71 .02

Body sizeWeight, kg 80�14 87�18 81�15 74�7a .01BMI 30�4.3 31�4 31�5.8 29�3 NSBSA, m2 1.89�0.2 1.99�0.3 1.9�0.2 1.8�0.1a .01

Anemic, % 67 65 50 79 NSMedications, %

Loop diuretics 68 65 69 70 NSThiazide diuretics 21 20 19 25 NSACE inhibitors 66 65 81 58 NSb-Blockers 66 45 56 92 <.001Aldosterone antagonist 20 40 19 4 <.01Calcium channel blockers 43 25 50 54 NS

Blood pressure, mm HgSystolic blood pressure 142�16.5 137�18 145�16 143�15 NSDiastolic blood pressure 73�11.4 73�14 75�11 73�10 NS

Three-dimensional echocardiographyEDVI, mL ⁄ m2 58�12 60�10 62�16 55�8 NSSVI, mL ⁄ m2 32�6 32�6 34�8 30�5 NSEF, % 54�6 54�5 54�6 55�6 NSLV mass, g ⁄ m2 78�22 78�16 85�22 73�26 NSEDV ⁄ mass ratio 0.80�0.24 0.80�0.2 0.77�0.24 0.83�0.26 NS

Laboratory resultsHemoglobin, gm ⁄ dL 11.6�2.1 12�2.2 12�2 11�2 NSHematocrit, % 36�4.9 36�5.5 37�5 36�4 NSBUN, mg ⁄ dL 32�17 35�16 31�22 30�15 NSCreatinine, mg ⁄ dL 1.5�0.6 1.5�0.5 1.6�0.7 1.4�0.6 NSeGFR, mL ⁄ min 52�20 49�15 53�24 53�22 NS

Abbreviations: ACE, angiotensin-converting enzyme; BMI, body mass index; BSA, body surface area; BUN, serum urea nitrogen;EDV, end-diastolic volume; EDVI, end-diastolic volume index; EF, ejection fraction; eGFR, estimated glomerular filtration rate; LV,left ventricular; NS, not significant; SVI, stroke volume index. aP<.05 vs whites by analysis of variance with post hoc Bonferonnicorrection.

blood volume measurements in patients with HEPEF january • february 2011 15

non-normality of the data. A P value�.05 was considered significant. SASversion 9.1 (SAS Institute Inc, Cary,NC) was used for all analyses.

ResultsThe patients studied were older adults,predominately women, with an averageNew York Heart Association (NYHA)class of 2.5�0.6 and a normal ejectionfraction (54%�6%). They had underly-ing chronic renal insufficiency similar toother large series of hospitalized HFPEFpatients,20,21 with average hemoglobinof 11.6�2.1 g ⁄dL. Racial subgroupsdiffered with regard to sex, body weightand size, and the use of b-blockerand aldosterone antagonists but notwith regard to blood pressure, echo-cardiographic, or laboratory assessments(Table I).

Anemia, as defined by WHO criteria,was present in 40 (67%) patients, similarto other series,22 and did not differ sig-nificantly by sex or race. However, byRBCV deficit, anemia was present inonly 21 of those patients (35% overall)(Figure). In all groups studied (white,

black, and Hispanic), there was a signifi-cant difference in the rate of anemiadiagnosed by WHO criteria as comparedwith measured RBCV deficit. None ofthe patients first classified as non-anemicby WHO criteria were then reclassifiedas anemic by BV analysis. Overall, in45% of whites, 25% of Hispanics, and25% of blacks, the diagnosis of anemiawas reclassified when using RBCV defi-cit compared with hemoglobin.

BV indices overall and by racial groupare shown in Table II. On average,patients with HFPEF demonstrated anexpanded BV, which was primarilyattributable to an increase in PV. Whileoverall BVs, red cell volumes, and PVsdiffered by race, these differences wereno longer significant when controllingfor differences in sex and body sizebetween cohorts (eg, % deviation didnot differ). The difference in the pre-valence of anemia as determined byhemoglobin and RBCV was in partattributable to greater absolute PV com-pensation in response to RBCV deficit.Specifically, among patients who werecorrectly classified by WHO criteria, PV

compensation for the red cell deficit wasan appropriate physiologic response,while for patients who were misclassifiedby WHO criteria in comparison to redcell volume measures, the PV compen-sation was excessive (Figure, Panel B).The PV overcompensation was higherin misclassified patients compared withcorrectly classified patients in all racialsubgroups, but this was particularly truefor blacks and Hispanics compared withwhites.

DiscussionThe principal findings in this study arethat among patients with HFPEF, theprevalence of anemia differs betweenWHO criteria that employ hemoglobinmeasurement as compared with BVanalysis, with an overestimate of theprevalence of anemia by the WHO cri-teria, in part due to an excess expansionof PV in response to the red blood celldeficit. This error was present in allracial subgroups. Finally, the rate of atrue anemia (eg, red blood cell deficit)was highest among Hispanics as com-pared with whites and blacks.

A

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Figure. Panel A: The prevalence of anemia in the overall cohort and in each racial subgroup by World Health Organization (WHO) criteria(blue bars) and by red blood cell (RBC) deficit (red bars). Panel B. Differences in plasma volume (PV) compensation (by volume andpercentage) between patients diagnosed correctly by WHO and RBCV criteria (real anemia) and those misclassified as anemic by WHOcriteria stratified by race.

blood volume measurements in patients with HEPEF january • february 201116

Anemia in Multi-Ethnic Groups. Al-though the American Hispanic popula-tionis the fastest-growingethnicminorityin the United States, there is a paucity ofdata on the prevalence of anemia in thisgroup compared with other ethnicitiesandnodata thatweareawareof regardingethnicdifferencesspecifically inthepopu-lationwithHFPEF.Availabledatadosug-gest important racial ⁄ethnic differencesintheprevalenceofanemia inthegeneralpopulation and the underlying cause. Inthe Third National Health and NutritionExamination Survey (NHANES III), theprevalence of anemia in persons olderthan 65 years varied significantly by race,with an overall prevalence of 10.6% thatwas lowest for non-Hispanic whites(9.0%),slightlyhigher inMexicanAmer-icans (10.4%), but substantially higher innon-Hispanic blacks (27.8%).13 Simi-larly, a study of the prevalence and inci-dence of anemia in patients with diabetesmellitus showed a higher prevalence ofanemia among blacks and mixed ethnici-ties than Hispanics, whites, or Asians.23

In that study, a multivariate model ofprevalent anemia that adjusted for sex,age, clinic site, utilization, proximate esti-matedglomerularfiltrationrate, albumin-uria, diabetes treatment, and EPO usefoundthattheoddsofanemiawerehigheramong blacks (odds ratio [OR], 2.26; 95%confidence interval [CI], 2.12–2.41),those of mixed ethnicity (OR, 1.37; 95%CI, 1.31–1.44), or Hispanic (OR, 1.15;95% CI, 1.07–1.24), compared withwhites. Finally, in a population-basedsample that evaluated anemia prevalenceand iron status among older Hispanics ofCaribbean origin compared with a cohortof whites, the prevalence of anemia washigher in older Hispanics than innon-Hispanic older whites after control-ling for relevant confounders. This was inpart attributable to significant ethnicdifferences in nutrient intake and intakeof specific food items that resulted indifferent iron stores.24 We found a higherpercentageofHispanicswithHFPEFwereanemic by both hemoglobin and by BVanalysis thanwhitesorblacks.

PV in Anemia and HF. Anemia inHF patients may be a result of iron

deficiency, hemodilution,19 anemia ofchronic disease,25 malnutrition,26 renalinsufficiency,26 or medication-inducedanemia.25 Among the population withadvanced systolic HF, hemodilution iscommon.27 Similarly, our data suggestthat a significant percentage of patientswith HFPEF have expansions of PVthat are beyond physiologic compensa-tion for the red blood cell deficit andare in part hemodilutional in nature.Indeed, chronic anemia in the absenceof HF is associated with PV expansionand edema because of decreased bloodviscosity and the resulting effects ofnitric oxide–mediated vasodilatation.25

As a result, there is a decline in sys-temic vascular resistance and, becauseof arterial under-filling, an activationof the renin-angiotensin system andconcomitant PV expansion.25 Accord-ingly, the PV expansion in anemicpatients replaces decreased red bloodcell mass12 in order to maintain a nor-mal BV. In HF patients, alterations inPV that occur in response to the under-lying cardiac and or renal dysfunctionand subsequent neurohormonal activa-tion further add to the physiologicallyexpanded PV in anemic patients andconfound the diagnosis as shown bythese data. Additionally, HFPEFpatients often have concomitant comor-bid conditions including obesity andrenal insufficiency, which affect PVregulation and could be an explanationfor the observed findings.

Clinical Implications. Appropriate treat-ment of anemia associated with HF mayimprove the outcomes of patients byenhancing physical function and qualityof life,26 but treatment requires anaccurate diagnosis and identification ofthe underlying etiology in order to selecteffective interventions. Commonly usedtreatments for nondilutional anemiawhen used in cases of hemodilutionalanemia can put the patient underunnecessary risk secondary to adverseeffects of medication and may contrib-ute to adverse outcomes.28,29 The cur-rent data raise the possibility thatfurther definition of the low hemoglobinphenotype in patients with HF usingTa

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blood volume measurements in patients with HEPEF january • february 2011 17

BV analysis could provide importantphysiologic insights regarding therapeu-tic interventions. Of course, such recom-mendations must await the formalperformance of clinical trials that aretesting such hypotheses30 and the recog-nition that PV is dynamically regulatedand fluctuates widely in response to mul-tiple physiologic signals.

LimitationsThe study is limited by the small samplesize with limited power to detect differ-ences between groups and the potentialfor a type II (beta) error. The use of

self-reports to classify race ⁄ethnicity,which is in part a clustering ofcommon genetic characteristics, is alsoinfluenced by social, environmental,and lifestyle factors that may have aneffect on cardiovascular health. Giventhe cross-sectional nature of our study,we cannot exclude the effect of residualunmeasured confounders. However,factors known to affect BV, includingbody size and sex, were accountedfor in the current analyses, and the useof medications that could alter BVdid not differ between the groupsstudied.

ConclusionsIn patients with HFPEF, the diagnosis ofanemia by hemoglobin is confounded byalterations in BV components. Thesedifferences are present in all racial sub-groups. Such data could have importantimplications for the diagnosis and man-agement of anemia in ethnic popula-tions with HFPEF.

Disclosures: This research wassupported by the NIH ⁄NIA (RO1AG027518-01A1). Dr. Maurer wassupported by a K24-AG036778-01A1from the NIH.

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