Table 1.

Characteristics of studies included in the review

Study/Reference/Year/Location/N	Median Age, yr [Mean]	Men, %	CKD Stage	Aim	Design	Setting and Recruitment Method	Participants	Exclusion Criteria	Health Literacy Measure	Outcome Variables Tested	Prevalence of Limited Health Literacy, %
Adeseun (34)	[52]	68	Incident dialysis (HD or PD)	Examine relationship between health literacy and CV disease risk factors	Cohort (baseline data)	Adults from transplant evaluation clinics taking part in the Dialysis Heart and Bone Study	100% with limited health literacy were black compared with 50% of those with adequate health literacy	Previous coronary revascularization, cardiac devices, or weight >350 lb	STOFHLA	BP, lipid profile, waist-to-hip ratio, BMI, tobacco use	21
2012
US
72
Boulware (35)	60	40	Nondialysis CKD 3–5	Compare the effectiveness of educational interventions on preemptive living donor kidney transplantation	Cohort (baseline data)	Nephrology clinics	46% White, 47% black,<1% Hispanic	<18 or >70 yr old, non-English speaking, previous transplant, cancer, heart failure, severe liver disease, PVD, HIV, unstable coronary artery disease	REALM	—	25
2013
US
130
Brice (24)	—	—	Prevalent HD	Validate TILS and SILS against STOFHLA	Cross-sectional	Adults from seven HD centers	English (96%) and Spanish speakers (4%)	<18 yr old, unable to speak English or Spanish, mental impairment defined by dialysis staff, poor vision	STOFHLA, SILS and TILS (English or Spanish)	—	45 (STOFHLA),22 (SILS)
2014
US
277
Cavanaugh 1 (21)^a	62	56	Incident HD	Measure the prevalence and associations of limited health literacy and risk of all-cause mortality	Cohort	Adults “eligible for a patient education program” from 77 dialysis units, health literacy measured if low literacy was suspected by case manager	52% White, 50% diabetic	<18 yr old, patients on nonpermanent dialysis, known cognitive impairment, non-English speakers, nursing home residents	REALM	Mortality	32
2010
US
480
Cavanaugh 2 (23)	[52]	51	Prevalent HD	Validate BHLS against REALM and STOFHLA	Cross-sectional	Adults from four dialysis units	73% Black	<18 or >80 yr old, dialysis initiation <1 mo, non-English speakers, cognitive impairment	BHLS (0–15), REALM, and STOFHLA	—	23 (BHLS) 27 (REALM) 8 (STOFHLA)
2015
US
143
Dageforde 1 (36)	[48]	64	Incident transplant	Compare health literacy between live and deceased donor kidney transplant recipients and live kidney donors	Retrospective chart review	Transplant recipients and donors at single transplant center surveyed for health literacy preoperatively	65% White LDR (n=103) DDR (n=152)	<18 yr old, no recorded answer to BHLS	BHLS (0–15)	Donor type, education, and demographics	12 (LDRs: 9%; DDRs: 14%)
2014
US
255
Dageforde 2 (37)	[53]	61	Dialysis (n=14) and nondialysis CKD (n=90)	Characteristics of attenders versus absentees for kidney transplant evaluation appointments	Cross-sectional	Convenience sample of patients scheduled for initial evaluation for kidney transplant at a single center	46% White	<18 yr old, non-English speakers, cognitive impairment	BHLS (0–15)	Attendance versus nonattendance	23 (14% dialysis; 24% CKD)
2015
US
104
Devraj (38)	45% over 60 yr old	47	Nondialysis CKD 1–4	Relationship between health literacy and eGFR	Cross-sectional	Adults attending follow-up nephrology outpatient appointments at a single center, given a $20 merchandise card to participate	40% White, 41% Hispanic	<21 yr old, non-English speaking, AKI, cognitive impairment defined by medical notes or if less than four on cognition screening test, poor visual acuity	NVS	eGFR (MDRD formula)	63
2015
US
150
Foster (39)	[58]	54	Prevalent dialysis (HD or PD)	Assess disaster preparedness in patients on dialysis	Cross-sectional	Adults approached during dialysis at six dialysis units	57% Black, 6% Spanish speaking, 94% English speaking	<18 yr old, unable to understand consent process	STOFHLA (English or Spanish)	Disaster preparedness	49.5
2011
US
238
Gordon (18)^a	[47]	57	Transplant	Relationship between health literacy, transplant knowledge, and graft function	Cross-sectional	Sequential transplant recipients from a single center recruited at post-transplant clinic visit for 30-min interview		<18 yr old, non-English-speaking, visually impaired, too unwell to participate	STOFHLA and REALM-T	Demographics and graft function	9
2011
US
124
Green (19)^a	64	57	Prevalent HD	Describe prevalence and associations of limited health literacy	Cohort (baseline data)	Patients from nine dialysis units included in an RCT of strategies for managing pain, sexual dysfunction, and depression	40% Black	<18 yr old, less than thrice-weekly dialysis, non-English speakers, cognitive impairment, considering switch to PD or transplantation	REALM	Demographics, SES, comorbidity	16
2011
US
260
Grubbs (20)^a	[52]	66	Prevalent HD	Association of poor health literacy with access to transplantation	Cross-sectional	Adults approached during dialysis session in five dialysis units	73% Black	<18 or >75 yr old, ethnicity other than black or white, <9 mo on dialysis, previous transplant, cognitive impairment	STOFHLA	Referral for transplant evaluation, wait listing, or transplantation	32
2009
US
62
McNaughton (40)	55	57	CKD 3–5, including dialysis or transplant if eGFR<60 ml/min per 1.73 m²	Relationship between limited health literacy and BP at ED presentation	Cross-sectional	Adults attending ED at a large quaternary hospital screened for health literacy as part of admission nursing assessment	Study included 31,902 patients, of whom 851 (3%) had kidney disease, 60% white	<18 yr old, nursing assessment or health literacy measure not completed, admitted with preeclampsia or alcohol withdrawal	BHLS (0–15)	BP at hospital presentation (in all ED attenders)	26^b
2014
US
851^b
Miller-Matero (41)	—	—	Referred for transplantation (dialysis or advanced CKD)	Assess health literacy of patients referred for solid organ transplantation	Cross-sectional	Patients considered for solid organ transplantation at a single center	—	—	REALM	Demographics, cognitive impairment, reading ability, numeracy (in all organ transplant recipients)	37.8
2015
US
95
Ricardo (42)	[58]	54	Nondialysis CKD 1–4	Association of limited health literacy with kidney function and CV risk factors	Cross-sectional	Adults with CKD recruited from seven clinical centers	52% White, 48% black	<21 or >74 yr old, polycystic kidney disease (43), Hispanic ethnicity	STOFHLA	eGFR (MDRD formula), BP, LDL cholesterol <100 mg/dl, HbA1c<7%, self-reported CV disease	16 (Black, 28%; white, 5%)
2014
US
2340
Robinson (43)	[50]	59	Prevalent transplant	Validate a sun-protection education program	RCT (baseline data)	Adults from two transplant programs	35% Black, 28% Hispanic, 36% white	<2 or >24 mo after transplant, non-Spanish speakers, <18 or >70 yr old, poor vision, ethnicity other than black, white, or Hispanic	STOFHLA (English or Spanish)	—	36 (Black, 58%; Hispanic, 54%;white, 0%)
2015
US
170
Taylor (44)	54	62	Incident dialysis (HD or PD), incident transplant and transplant waitlisted (prevalent dialysis and nondialysis CKD)	Describe prevalence and associations of limited health literacy	Cohort (baseline data)	Adults approached for notes review and survey from all 71 United Kingdom renal units	Representative nationwide sample, 79% white, patients with CKD not on dialysis were all preemptively waitlisted for transplant	<18 or >75 yr old or unable to provide informed consent	SILS	Demographics, SES, comorbidity	16 (Dialysis, 18%; CKD wait listed, 9%; incident transplant, 12%)
2015
UK
5520
Weng (45)	[55]	60	Prevalent transplant	Prevalence and correlates of medication nonadherence	Cross-sectional	Adults approached during a transplant clinic visit at a single center, offered $15	58% White, 27% black, median 2.9 yr post-transplant	<6 mo Post-transplant, <18 yr old, non-English speakers, unable to consent, dual organ transplant	STOFHLA	Medication nonadherence	2.4
2013
US
252
Wright (47)^a	58	53	Nondialysis CKD 1–5	Measure awareness and knowledge of CKD to develop a CKD knowledge survey	Cross-sectional	Adults attending a follow-up nephrology clinic appointment at a single center, offered $10	83% White	<18 yr old, non-English speakers, kidney transplant or dialysis, vision or cognitive impairment	REALM	Kidney disease knowledge	18
2011
US
401
Wright-Nunes (46)	58	54	Nondialysis CKD 1–5	Assess feasibility and effect of a physician-delivered education tool to increase CKD knowledge	Clinical trial, (baseline data)	Adults at single center asked to complete a survey (written or read aloud), offered monetary compensation	77% White, 78% CKD 3–5	<18 yr old, non-English speakers, kidney transplant or dialysis, vision or cognitive impairment	REALM	—	22
2013
US
154^c

Outcome variables are listed only if statistical models included health literacy as an exposure variable. US, United States; HD, hemodialysis; PD, peritoneal dialysis; CV, cardiovascular; STOFHLA, Short Test of Functional Health Literacy in Adults; BMI, body mass index; PVD, peripheral vascular disease; REALM, Rapid Evaluation of Adult Literacy in Medicine; —, data unavailable or no outcomes tested; TILS, Two-Item Literacy Screener; SILS, Single-Item Literacy Screener; BHLS, Brief Health Literacy Screener; LDR, live donor recipient; DDR, deceased donor recipient; NVS, Newest Vital Sign; MDRD, Modification of Diet in Renal Disease; REALM-T, transplant-specific version of the Rapid Estimate of Adult Literacy in Medicine; RCT, randomized controlled trial; ED, emergency department; HbA1c, hemoglobin A1c;UK, United Kingdom; SES, socioeconomic status.
↵a Studies included in the 2012 review by Fraser et al. (17).
↵b Frequencies from personal communication with the authors (C. McNaughton).
↵c After excluding 401 from ref. 48.