Original Investigation

Associations of Health Literacy With Dialysis Adherence andHealth Resource Utilization in Patients Receiving Maintenance

Hemodialysis

Jamie A. Green, MD, MS,1 Maria K. Mor, PhD,2,3 Anne Marie Shields, MSN, RN,2

Mary Ann Sevick, ScD, RN,2,4 Robert M. Arnold, MD,4,5 Paul M. Palevsky, MD,6,7

Michael J. Fine, MD, MSc,2,4 and Steven D. Weisbord, MD, MSc2,6,7

Background: Although limited health literacy is common in hemodialysis patients, its effects on clinicaloutcomes are not well understood.

Study Design: Observational study.Setting & Participants: 260 maintenance hemodialysis patients enrolled in a randomized clinical trial of

symptom management strategies from January 2009 through April 2011.Predictor: Limited health literacy.Outcomes: Dialysis adherence (missed and abbreviated treatments) and health resource utilization (emergency

department visits and end-stage renal disease [ESRD]-related hospitalizations).Measurements: We assessed health literacy using the Rapid Estimate of Adult Literacy in Medicine

(REALM) and used negative binomial regression to analyze the independent associations of limited healthliteracy with dialysis adherence and health resource utilization over 12-24 months.

Results: 41 of 260 (16%) patients showed limited health literacy (REALM score, �60). There were 1,152missed treatments, 5,127 abbreviated treatments, 552 emergency department visits, and 463 ESRD-relatedhospitalizations. Limited health literacy was associated independently with an increased incidence of misseddialysis treatments (missed, 0.6% vs 0.3%; adjusted incidence rate ratio [IRR], 2.14; 95% CI, 1.10-4.17),emergency department visits (annual visits, 1.7 vs 1.0; adjusted IRR, 1.37; 95% CI, 1.01-1.86), andhospitalizations related to ESRD (annual hospitalizations, 0.9 vs 0.5; adjusted IRR, 1.55; 95% CI, 1.03-2.34).

Limitations: Generalizability and potential for residual confounding.Conclusions: Patients receiving maintenance hemodialysis who have limited health literacy are more likely

to miss dialysis treatments, use emergency care, and be hospitalized related to their kidney disease. Thesefindings have important clinical practice and cost implications.Am J Kidney Dis. 62(1):73-80. © 2013 by the National Kidney Foundation, Inc. Published by Elsevier Inc. Allrights reserved.

INDEX WORDS: Health literacy; hemodialysis; outcomes.

Editorial, p. 3

Health literacy refers to the group of skills neededfor an individual to function effectively in the

health care environment and act suitably on healthinformation.1 Patients with limited health literacymay have difficulty with many of the tasks requiredfor chronic disease self-management, such as locatingproviders and services, communicating with clini-cians, understanding treatment regimens, and imple-menting self-care instructions. Studies in various pa-tient populations show that limited health literacy isassociated with poorer health-related knowledge,2,3

increased health resource utilization,4-6 decreased pre-ventive health care,7,8 poorer medication understand-ing,6,9,10 poorer overall health status,6,11,12 and highermortality.12-15 Consequently, several national organi-zations in the United States, including the Institute ofMedicine, American Medical Association, and Depart-

ment of Health and Human Services, have established

Am J Kidney Dis. 2013;62(1):73-80

initiatives to address health literacy in order to im-prove health care access, quality, and costs.16-18

Little is known regarding the effects of limitedhealth literacy on patients with end-stage renal dis-ease (ESRD). Preliminary studies suggest that limitedhealth literacy affects up to one-third of patients on

From the 1Nephrology Department, Geisinger Medical Center,Danville; 2Center for Health Equity Research and Promotion, VAPittsburgh Healthcare System; 3Department of Biostatistics, Gradu-ate School of Public Health; 4Division of General Internal Medi-cine; 5Section of Palliative Care; and 6Renal-Electrolyte Division,University of Pittsburgh; and 7Renal Section, VA Pittsburgh Health-care System, Pittsburgh, PA.

Received July 22, 2012. Accepted in revised form December 21,2012. Originally published online January 25, 2013.

Address correspondence to Jamie A. Green, MD, GeisingerCenter for Health Research, 100 N Academy Ave, Danville, PA17822. E-mail: jgreen1@geisinger.edu

© 2013 by the National Kidney Foundation, Inc. Published by ElsevierInc. All rights reserved.

0272-6386/$36.00

http://dx.doi.org/10.1053/j.ajkd.2012.12.014

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Green et al

maintenance hemodialysis therapy19,20 and is associ-ated with decreased access to kidney transplanta-tion,19,21 higher blood pressure,22 and increased mor-tality.20 Potential mediators of the relationship betweenlimited health literacy and these clinically meaningfulpatient outcomes are unknown. We sought to assessthe associations of limited health literacy with dialysisadherence (missed and abbreviated treatments) andhealth resource utilization (emergency department vis-its and ESRD-related hospitalizations) in patientstreated with maintenance hemodialysis. We also ex-plored the associations of health literacy with kidneytransplantation and mortality.

METHODS

StudyParticipants

Patients in this prospective cohort study included participants ina larger randomized trial comparing 2 strategies for the manage-ment of pain, sexual dysfunction, and depression in maintenancehemodialysis patients (the SMILE [Symptom Management Involv-ing End-Stage Renal Disease] Study).23 In this parent trial, patientswere followed up during a 2- to 12-month observational period andthen randomly assigned to 12-month participation in either a“feedback” arm (monthly assessment of symptoms provided torenal providers who remained in charge of symptom treatment) ora “nurse management arm” (monthly assessment of symptomswith treatment facilitated by a nurse manager). Neither interven-tion was designed to address the issue of limited health literacy.

Participants in the SMILE Study were enrolled from January2009 through March 2010 and followed up until April 2011.Eligible patients were 18 years or older receiving maintenancethrice-weekly outpatient hemodialysis at 1 of 9 dialysis units in oraround Pittsburgh, PA. We excluded non-English speakers, pa-tients with cognitive dysfunction,24 and those considering transferto peritoneal dialysis therapy and/or awaiting living donor kidneytransplantation in order to optimize the proportion of study partici-pants who would remain on hemodialysis treatment for the dura-tion of the parent trial. The study was approved by the institutionalreview boards of the VA Pittsburgh Healthcare System, Universityof Pittsburgh, and the Western Institutional Review Board.

BaselineDataCollection

As part of routine baseline data collection, health literacy wasassessed at the time of enrollment by trained research personnelusing the Rapid Estimate of Adult Literacy in Medicine (REALM),a widely used word recognition tool that has been validated againstgeneral measures of literacy25 and other health literacy screeningtools.26,27 It also has been shown to correlate with outcomes inhemodialysis.20 To complete the REALM, patients are asked toread and correctly pronounce a list of common medical words andlay terms for body parts and illnesses. REALM scores range from0-66 based on the total number of correctly pronounced words,with higher scores indicating greater health literacy. Limited healthliteracy is defined as a score of 60 or lower, which correlates with areading level of less than the 9th grade.

We used patient interviews and dialysis chart reviews to assessbaseline demographic and clinical characteristics, including age, sex,race, educational level, income, employment status, dialysis vintage,dialysis schedule, type of vascular access, history of kidney transplan-tation, and comorbid illness burden.28 We reviewed dialysis charts torecord baseline hemoglobin levels; serum calcium, phosphorus, albu-

min, and intact parathyroid hormone levels; and Kt/V.

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StudyOutcomes

We followed up patients for as long as 24 months. The primaryoutcomes were dialysis adherence, emergency department visits,and hospitalizations related to ESRD. We focused on ESRD-related hospitalizations rather than all-cause hospitalization be-cause we hypothesized that limited health literacy would beassociated with hospital admissions due to ESRD-related compli-cations (eg, volume overload and access-related infections). Weassessed the primary outcomes monthly by reviewing dialysischarts and interviewing patients and dialysis staff. We categorizeddialysis adherence as missed and abbreviated treatments. Wedefined missed treatments as the proportion of monthly scheduleddialysis treatments that the patient missed other than for vacationor hospitalization, and abbreviated treatments as the proportion ofmonthly hemodialysis sessions that were shortened by patientrequest by at least 15 minutes. In addition, because the distributionof missed treatments was highly skewed, we also assessed theproportion of patients who missed 3 or more treatments per year.These data were collected directly from dialysis charts. Becausedocumentation of emergency department visits commonly are miss-ing from outpatient dialysis charts, we assessed emergency depart-ment visits using patient interviews. We defined hospitalizations forreasons related to ESRD based on hospital discharge summaries withprimary discharge diagnoses related to kidney failure, cardiovasculardisease, volume overload, or hemodialysis access, including infec-tion. The consensus of 2 investigators (J.A.G. and S.D.W.) wasrequired to identify ESRD-related hospitalizations. We also trackedkidney transplantation and mortality as secondary outcomes. Wereviewed dialysis charts and interviewed dialysis staff to assesskidney transplantation status (receipt of a new kidney transplant sinceenrollment) and mortality. We defined mortality as all-cause death orterminal withdrawal from dialysis therapy.

Statistical Analyses

We describe patients’ baseline clinical characteristics usingmedians and interquartile ranges (IQRs) for continuous variablesand frequencies and/or proportions for discrete variables. We usednegative binomial regression to model the association of healthliteracy with missed dialysis treatments, abbreviated dialysis treat-ments, emergency department visits, and ESRD-related hospitaliza-tions. Negative binomial regression allows for the modeling ofoutcomes that are counts (eg, number of missed dialysis treat-ments) while accounting for potentially different follow-up time(exposure) for each participant. Negative binomial models wereused due to the presence of overdispersion in the data (increasedvariability), which is not addressed appropriately in Poisson regres-sion.29 For dialysis adherence, we considered the number ofdialysis sessions that should have been attended and completed infull as the exposure variable. For emergency department visits andhospitalizations, we used patient-specific follow-up time. In orderto adjust for treatment assignment, patients had separate datarecords for events during the observation and intervention phasesof the parent trial. A clustered sandwich estimator was used for thevariance estimates to account for the nonindependence of observa-tions from the same patient. We used logistic regression to assessthe association of health literacy with kidney transplantation and aproportional hazards model to explore the association of limitedhealth literacy with mortality. Patients were considered censored atstudy end or at the time of withdrawal. All models were adjustedfor potentially confounding variables, identified a priori, includingage, sex, race, employment, income, comorbid illness burden,dialysis vintage in years, type of vascular access, and randomiza-tion group. Education was not included as a potential confounderdue to evidence of multicollinearity. We conducted additional

analyses in which we added dialysis adherence (percentage of

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Health Literacy and Outcomes in Hemodialysis

sessions missed or abbreviated) to the multivariable model assess-ing the relationship between health literacy and health resourceutilization. This provided an estimate of the degree to whichdialysis adherence mediated the association of limited healthliteracy with health resource utilization. All analyses included afixed effect for the dialysis unit and an indicator variable fordialysis schedule (Monday/Wednesday/Friday vs Tuesday/Thurs-day/Saturday) to account for the unit of randomization of theparent trial.23 In addition, we used multiple imputation to accountfor missing data in income due to the amount of missing data andthe observed relationship with limited health literacy. Statisticalsignificance was denoted by 2-tailed P � 0.05. All analyses wereconducted using SAS, version 9.3 (SAS Institute Inc), and Stata,version 12.0 (StataCorp LP). Sample size was fixed and based onthe design of the parent trial, which had �80% power to detect aneffect size of 0.5 for each symptom.30

RESULTS

StudyPopulation

We screened 439 patients for the parent trial. Eighty-five patients declined participation, 39 were found tobe ineligible, and 27 enrolled but died or withdrewprior to data collection. Thus, we enrolled and ob-tained baseline data for 288 patients. There were nodifferences in key demographic or clinical variablesbetween patients who did and did not enroll. Of 288patients participating in the parent trial, 260 (90%)completed the baseline health literacy assessment andwere included in the present study. Participants whorefused the REALM were more likely to have lowerthan high school education than patients who com-pleted this assessment. Reasons for refusal were notedin half the cases; all reasons provided were due tovisual impairment. Median follow-up for the 260patients included in the present analysis was 19.5months.

Median age of the study cohort was 62 [IQR,55-73] years, 58% were men, 40% were AfricanAmerican, 12% did not complete high school, and49% had an annual income �$30,000 (Table 1).Forty-one of 260 patients (16%) showed limited healthliteracy (REALM scores of 45-60 [n � 34], 19-44[n � 6], and �19 [n � 1]). Compared with those withadequate health literacy, patients with limited healthliteracy were more likely to be African American(59% vs 36%; P � 0.009), use a fistula or graft fordialysis rather than a catheter at the time of enrollment(93% vs 77%; P � 0.02), have less education (P �0.001), have lower incomes (P � 0.004), and havehigher levels of comorbidity (P � 0.02; Table 1).

AssociationBetweenHealth Literacy andDialysisAdherence

The median frequency of missed dialysis treat-ments in patients with limited health literacy was0.6% [IQR, 0.3%-2.1%] compared to 0.3% [IQR,

0%-1.6%] in those with adequate health literacy. The

Am J Kidney Dis. 2013;62(1):73-80

median frequency of abbreviated treatments in pa-tients with limited health literacy was 4.8% [IQR,1.2%-9.4%] compared to 4.1% [IQR, 1.4%-10.7%] inthose with adequate health literacy (Table 2). In unad-justed analyses, limited health literacy was associatedwith an increased incidence of missed dialysis treat-ments (incidence rate ratio [IRR], 3.64; 95% confi-dence interval [CI], 1.32-10.02), but not abbreviatedtreatments (IRR, 1.08; 95% CI, 0.67-1.72). The asso-ciation of limited health literacy with missed dialysistreatments remained statistically significant after adjust-ment for potential confounders (adjusted IRR, 2.14;95% CI, 1.10-4.17). There was no independent associa-tion of limited health literacy with abbreviated dialysistreatments (adjusted IRR, 1.17; 95% CI, 0.79-1.74; Table3). We observed a modest non–statistically significantdifference in the proportion of patients who missed 3 ormore treatments per year (29% with limited vs 22% withadequate health literacy; Table 2). However, our studyhad insufficient power to adequately compare this binaryoutcome across groups.

AssociationBetweenHealth Literacy andHealthResourceUtilization

The median number of annual emergency depart-ment visits was greater in patients with limited healthliteracy compared with those with adequate healthliteracy (1.7 [IQR, 0.8-2.7] vs 1.0 [IQR, 0-2.2]), aswas the median number of annual ESRD-related hos-pitalizations (0.9 [IQR, 0-2.1] vs 0.5 [IQR, 0-1.8];Table 2). In unadjusted analyses, there was a borderlineassociation of limited health literacy with increasedemergency department visits (IRR, 1.41; 95% CI, 1.00-1.98) and ESRD-related hospitalizations (IRR, 1.56;95% CI, 0.98-2.48). In adjusted models, limited healthliteracy was associated independently with increasedemergency department visits (adjusted IRR, 1.37; 95%CI, 1.01-1.86) and ESRD-related hospitalizations (ad-justed IRR, 1.55; 95% CI, 1.03-2.34; Table 3). To ex-plore whether dialysis adherence was mediating theseassociations, we conducted sensitivity analyses that in-cluded dialysis adherence in these multivariable models;results were essentially unchanged (emergency depart-ment visits: adjusted IRR, 1.35 [95% CI, 0.99-1.84]; andESRD-related hospitalizations: adjusted IRR, 1.55 [95%CI, 1.03-2.33]), indicating that dialysis adherence doesnot mediate these relationships.

AssociationsBetweenHealth Literacy andKidneyTransplantation andMortality

Overall, 16 patients (6%) received a kidney trans-plant during study participation and 55 (21%) died(Table 2). We did not find an association betweenlimited health literacy and receipt of a kidney trans-

plant (adjusted odds ratio, 0.76; 95% CI, 0.14-4.20).

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Green et al

Limited health literacy also was not associated withmortality in unadjusted analyses (hazard ratio [HR],1.11; 95% CI, 0.53-2.30) or after adjustment (adjustedHR, 0.96; 95% CI, 0.21-2.17). Sensitivity analyses inwhich REALM scores were considered as a continu-ous variable also did not show an association betweenlimited health literacy and mortality (adjusted HR,1.20; 95% CI, 0.65-2.21).

DISCUSSION

In this prospective cohort study of patients receiv-ing maintenance hemodialysis, we found that limitedhealth literacy was associated independently with anincreased incidence of missed dialysis treatments,emergency department visits, and hospitalization re-lated to ESRD. These novel findings have importantimplications for the clinical care and health care costs

Table 1. Baseline

CharacteristicOverall Population

(N � 260)Lim

Age (y) 62 [55-73]

Male sex 150 (58)

African American race 103 (40)

Education�High school 31 (12)High school equivalent 81 (31)�High school 146 (57)

Income�$30,000/y 127 (49)�$30,000/y 86 (33)Unknown 47 (18)

Employment 33 (13)

Dialysis vintage (y) 2.2 [0.9-4.7]

MWF dialysis schedule 172 (66)

Dialysis accessCatheter 54 (21)AV fistula or graft 206 (79)

CCI score1-2 63 (25)3-4 96 (37)�5 97 (38)

Laboratory valuesHemoglobin (g/dL) 11.6 [10.9-12.3]Albumin (g/dL) 3.8 [3.5-4.1]Calcium (mg/dL) 8.9 [8.5-9.2]Phosphorus (mg/dL) 5.0 [4.3-6.0]iPTH (pg/mL) 253 [167-384]Kt/V 1.5 [1.4-1.6]

Note: Categorical variables are presented as number (percension factors for units: calcium in mg/dL to mmol/L, �0.2495; phos

Abbreviations: AV, arteriovenous; CCI, Charlson ComorbidityFriday.

aDenotes comparison of patients with limited versus adequate

of this patient population.

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Our results indicate that patients with limited healthliteracy are more likely to miss, but not abbreviate,dialysis treatments, although the absolute numbers ofmissed treatments were relatively small. This findingwas not unexpected because past studies demonstratepoor correlation between missing and abbreviatingbehaviors.31 Commonly, the abbreviation of dialysisrelates to clinical factors, such as the development ofintradialytic hypotension, symptoms such as cramp-ing, or problems with vascular access that are unlikelyto be related to a patient’s literacy level. Conversely,missing dialysis is more likely to reflect suboptimalself-care (personal medical care performed by thepatient based on acquired knowledge and skills),which has been proposed as a possible mediatorlinking limited health literacy with adverse outcomesin patients with ESRD.32 There also is evidence that

y Characteristics

Health Literacyn � 41)

Adequate Health Literacy(n � 219) Pa

[57-73] 63 [55-73] 0.8

7 (66) 123 (56) 0.3

4 (59) 79 (36) 0.009

�0.0014 (34) 17 (8)7 (42) 64 (29)0 (24) 136 (63)

0.0042 (54) 105 (48)6 (14) 80 (37)3 (32) 34 (14)

3 (7) 30 (14) 0.3

[1.0-4.1] 2.2 [0.8-4.7] 0.8

4 (59) 148 (68) 0.3

0.023 (7) 51 (23)8 (93) 167 (77)

0.026 (14) 57 (26)3 (32) 83 (39)2 (54) 75 (35)

[11.2-12.3] 11.6 [10.9-12.2] 0.2[3.5-4.1] 3.8 [3.6-4.1] 0.6[8.5-9.1] 8.9 [8.5-9.3] 0.3[4.1-6.9] 5.0 [4.3-5.9] 0.4[189-383] 244 [165-386] 0.7[1.4-1.7] 1.5 [1.4-1.6] 0.8

; continuous variables, as median [interquartile range]. Conver-us in mg/dL to mmol/L, �0.3229.; iPTH, intact parathyroid hormone; MWF, Monday/Wednesday/

h literacy.

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2

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12

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2661.5

tage)phorIndex

missed dialysis treatments are more predictive of

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Health Literacy and Outcomes in Hemodialysis

adverse outcomes than abbreviated treatments,33 em-phasizing the potential importance of our findingsassociating limited health literacy with missedtreatments.

Although we did not assess reasons for unexcusedmissed treatments, limited health literacy may contrib-ute to poorer patient knowledge of the importance ofregular dialysis attendance and/or reduced self-efficacy, which reflects a patient’s confidence thatthey can perform an action such as attending dialysisregularly.32 Several studies show a relationship be-tween limited health literacy and poorer kidneydisease–related knowledge. Wright et al34 showedthat patients with low health literacy were less likelyto have knowledge about topics integral to self-care

Table 2. Associations of Health Literacy With PatientOutcomes

Outcomes

LimitedHealth

Literacy(n � 41)

AdequateHealth

Literacy(n � 219)

Dialysis adherenceMissed sessions

Total missed 323 829% Sessions missed 0.6 [0.3-2.1] 0.3 [0-1.6]Missed �3 sessions/y 12 (29) 48 (22)

Abbreviated sessionsTotal abbreviated 787 4,340% Sessions abbreviated 4.8 [1.2-9.4] 4.1 [1.4-10.7]

Health resource utilizationEmergency department visits

Total visits 112 440Annual visits 1.7 [0.8-2.7] 1.0 [0-2.2]

ESRD-related hospitalizationsTotal hospitalizations 97 366Annual hospitalizations 0.9 [0-2.1] 0.5 [0-1.8]

Kidney transplantation 2 (5) 14 (6)

Death or terminal withdrawal 10 (24) 45 (21)

Note: Values for categorical variables are given as number ornumber (percentage); values for continuous variables, as me-dian [interquartile range].

Abbreviation: ESRD, end-stage renal disease.

Table 3. Associations of Limited Health Literacy W

Outcomes Unadjusted IRR (95%

Dialysis adherenceMissed 3.64 (1.32-10.02)Abbreviated 1.08 (0.67-1.72)

Health resource utilizationEmergency department visits 1.41 (1.00-1.98)ESRD-related hospitalizations 1.56 (0.98-2.48)

Abbreviations: CI, confidence interval; ESRD, end-stage renalaAdjusted for age, sex, race, employment, income, comorbid c

access, dialysis unit, and randomization group.

Am J Kidney Dis. 2013;62(1):73-80

practices in chronic kidney disease. In another studyof patients at high risk of chronic kidney disease,patients with low health literacy were less likely to beaware of their risk.35 Limited health literacy also hasbeen associated with poorer self-efficacy in patientswith diabetes and human immunodeficiency virus(HIV) infection,36,37 although no study has examinedthis relationship in patients with kidney disease. How-ever, greater self-efficacy has been associated withbetter self-management behaviors in patients withESRD38 and improved medication adherence in kid-ney transplant recipients.39 Research to elucidatewhether the association of limited health literacy withlower dialysis attendance is mediated by poor self-care, limited knowledge, and/or impaired self-effi-cacy may inform efforts to develop targeted interven-tions to increase dialysis adherence and improvepatient-centered outcomes.

Our findings also show that patients with limitedhealth literacy are more likely to visit emergencydepartments and be hospitalized for reasons related totheir kidney disease. This is consistent with studies ofother patient populations showing that limited healthliteracy is associated with increased health resourceutilization.4-6,40,41 Several mechanisms have been pro-posed to explain this relationship in patients withchronic illness, including poorer self-managementskills and/or reduced access to care. Limited healthliteracy may limit the ability of patients with ESRD toadhere to prescribed pharmacologic therapies,42 at-tend dialysis regularly (as shown in this study), followdietary and fluid restrictions,43 and self-monitor impor-tant disease parameters (eg, blood pressure andweight), resulting in poorer disease control and greateruse of health care services. It also is possible thatlimited health literacy affects health resource utiliza-tion through lack of insurance or transportation, result-ing in impaired access to care. Although our analysesdid not suggest that dialysis adherence mediates theassociation of limited health literacy with emergencydepartment visits or hospitalizations, our study wasnot designed to investigate other factors that may

ialysis Adherence and Health Resource Utilization

P Adjusted IRR (95% CI)a P

0.01 2.14 (1.10-4.17) 0.030.8 1.17 (0.79-1.74) 0.4

0.05 1.37 (1.01-1.86) 0.040.06 1.55 (1.03-2.34) 0.04

se; IRR, incidence rate ratio.ions, dialysis vintage in years, dialysis schedule, type of vascular

ith D

CI)

diseaondit

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Green et al

mediate this relationship. Nonetheless, others haveshown that increased health resource use associatedwith limited health literacy translates into increasedhealth care costs.44 With continued escalation in thecosts associated with caring for the ESRD popula-tion,45 efforts to address limited health literacy mayprovide a means to reduce potentially avoidable healthcare use and expenditures in this patient group.

Unlike certain past studies, we did not find anindependent association of limited health literacy withkidney transplantation or mortality.19-21 The absenceof an association may relate to the smaller number ofpatients and overall events in our study, which ren-dered our analyses underpowered for these outcomes.Differences in literacy assessment tools and patientpopulations also may explain the divergent results.Nonetheless, our findings that limited health literacyis associated with missed dialysis treatments andincreased emergency department visits and ESRD-related hospitalizations provide plausible clinicalmechanisms whereby limited health literacy couldincrease patients’ mortality risk. In adjusted analyses,missed dialysis treatments were associated with mor-tality in our study (data not shown), which also hasbeen confirmed in other studies.33,46 Future studies oflarger populations of patients are needed to clarify thenature of these relationships.

Our study has several limitations. First, we as-sessed only one domain of health literacy: print lit-eracy/reading skills. Health literacy now is recog-nized to encompass a variety of other domains,including oral literacy (listening and speaking skills),numeracy (calculating ability), and navigation skills(information-seeking behavior), that may be impor-tant determinants of health outcomes. Efforts areunderway to develop more comprehensive measuresof health literacy that may be used in the future.47

Second, because these analyses were ancillary to aclinical trial that did not intervene on limited healthliteracy, we are unable to determine whether theassociations of limited health literacy with clinicaloutcomes are causal. Third, although we adjusted formultiple potential demographic and clinical confound-ers in our analyses, there is the potential for unmea-sured residual confounding. Fourth, our definition ofemergency department visits was based on self-report,not documentation in the medical record. However, thetendency for patients to under- rather than over-reportuse of health care services suggests that our findingsregarding emergency department visits are valid.48 Fifth,because our findings are based on data derived frompatients participating in a clinical trial, our sample sizewas fixed and relatively small, limiting the power of ouranalyses, particularly those of kidney transplantation and

mortality. Sixth, the absolute numbers of events in our

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study were small in patients with and without limitedhealth literacy, which may have been related to thesymptom management provided by the parent trial,although in the final trial analysis, the overall interven-tion effect on symptom burden was small and no signifi-cant differences were found by randomization group.30

Furthermore, because our patients were pooled from arandomized trial, it is unlikely that the interventionswould impact on the outcomes of this cohort studydifferently in patients with and without limited healthliteracy. Larger studies are needed to determine theprecise magnitude of the effect of limited health literacyon the outcomes of interest. Seventh, based on theirdemographic characteristics, participants who refusedthe REALM may have been more likely to have lowhealth literacy, which may have introduced nonresponsebias. Finally, our patients were drawn from a singlegeographic area and by virtue of being enrolled in aclinical trial, may not be fully representative of thebroader dialysis population.

Despite these limitations, our findings suggest thatefforts to address health literacy in the hemodialysispopulation may be important. Promising interventionsinclude disease self-management programs and “teach-to-goal” support, which have been shown to improveself-care behaviors and reduce hospitalizations andmortality in patients with heart failure.49,50 In addi-tion, a toolkit is available for clinicians to incorporatehealth literacy universal precautions into daily prac-tice to ensure that health information is delivered inways that are understandable and usable by all pa-tients.51 Finally, routine screening for low healthliteracy may help providers recognize at-risk patientswho may need tailored care when resources are lim-ited. We and other investigators previously have shownthat educational attainment alone is a poor surrogatefor health literacy status.52,53 Although screening forlow health literacy historically has been discourageddue to the potential for inducing shame,54 brief screen-ing tools such as the Newest Vital Sign55 or single-item screening questions such as “How confident areyou filling our medical forms by yourself?”56,57 maybe useful in the appropriate clinical setting.

In conclusion, limited health literacy is common inmaintenance hemodialysis patients and is associatedwith suboptimal dialysis adherence and increasedhealth resource use. Although preliminary, these find-ings provide insight into the potential clinical impor-tance of limited health literacy in the hemodialysispopulation. Efforts to better understand how healthliteracy affects patient knowledge, self-efficacy, self-care behaviors, and access to care will help inform thedevelopment of interventions to reduce the impact oflimited health literacy on patient-centered outcomes

in this patient population with long-term illness.

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Health Literacy and Outcomes in Hemodialysis

ACKNOWLEDGEMENTS

Support: This study was funded by a grant from the USDepartment of Veterans Affairs Health Services Research andDevelopment Service (Dr Weisbord; HSR&D IIR 07-190) and aClinical Scientist in Nephrology Fellowship Grant from the Ameri-can Kidney Fund (Dr Green). The opinions expressed in this articleare those of the authors and do not represent the views of the USDepartment of Veterans Affairs or the US Government. Dr Greencompleted this study while at the University of Pittsburgh butcurrently is an employee of Geisinger Medical Center.

Financial Disclosure: The authors declare that they have noother relevant financial interests.

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