Do Subjective Measures Improve the Ability to Identify Limited Health Literacy in a Clinical Setting?

Melody S. Goodman; Richard T. Griffey; Christopher R. Carpenter; Melvin Blanchard; Kimberly A. Kaphingst

doi:10.3122/jabfm.2015.05.150037

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Table 1. Demographic Characteristics of Participants in the Overall, Estimation, and Validation Samples

Variables	Overall (N = 911)		Estimation (n = 456)		Validation (n = 455)		P value^*
Variables	n	%	n	%	n	%	P value^*
Sex
Male	353	38.7	174	38.2	179	39.3	.83^*
Female	558	62.3	282	61.8	276	60.7	.79^*
Education
<High school	156	17.1	78	17.1	78	17.1	1.00^*
High school	395	43.4	201	44.0	194	42.6	.78^*
>High school	360	39.5	177	38.8	183	40.2	.79^*
Race
White	308	33.8	151	33.1	157	34.5	.80^*
Black	603	66.2	305	66.9	298	65.5	.72^*
Difficulty with written information
Always/often/sometimes	251	27.6	151	20.4	100	22.0	.79^*
Rarely/never	660	72.4	305	79.6	355	78.0	.60^*
Confidence in filling out medical forms
Not at all/a little bit/somewhat	348	38.2	179	39.3	169	37.1	.67^*
Quite a bit/extremely confident	563	61.8	277	60.8	286	62.9	.61^*
Help reading hospital material
Always/often/sometimes	233	25.6	123	27.0	110	24.2	.63^*
Rarely/never	678	74.4	333	73.0	345	75.8	.40^*
Rapid Estimation of Adult Literacy in Medicine, Revised
Limited health literacy	418	45.9	205	45.0	213	46.8	.71^*
Adequate health literacy	493	54.1	251	55.0	242	53.2	.69^*
Newest Vital Sign
Limited health literacy	578	63.4	292	64.0	286	62.9	.79^*
Adequate health literacy	333	36.6	164	36.0	169	37.1	.83^*
Brief Health Literacy Screen score, mean (SD)	12.1	2.8	12.1	2.7	12.1	2.8	.78^{^†}
Age (years), mean (SD)	48.5	14	48.5	14.0	48.4	14.1	.88^{^†}

Data are n (%) unless otherwise indicated.
↵* Two-sample test for proportions.
↵† Two-sample t test.
SD, standard deviation.

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Table 2. Logistic Regression Models Estimating Limited Health Literacy against the Rapid Estimate of Adult Literacy in Medicine, Revised

Model	Demographics Only				SILS												BHLS
Model	Demographics Only				Difficulty with Written Information				Confidence Filling out Medical Forms				Help Reading Hospital Materials				BHLS
Predictors	OR	95% CI^*		P value	OR	95% CI^*		P value	OR	95% CI^*		P value	OR	95% CI^*		P value	OR	95% CI^*		P value
Age	0.99	0.98	1.01	.34	0.99	0.97	1.01	.21	0.99	0.98	1.01	.21	0.99	0.98	1.01	.32	0.99	0.97	1.01	.19
Sex (reference = male)
Female	0.45	0.29	0.71	<.01	0.45	0.28	0.72	<.01	0.45	0.28	0.70	<.01	0.47	0.30	0.74	<.01	0.45	0.28	0.71	<.01
Race (reference = white)
Black	8.25	4.89	13.90	<.01	8.76	5.10	15.06	<.01	8.10	4.80	13.67	<.01	8.25	4.87	14.00	<.01	8.21	4.83	13.96	<.01
Education (reference = high school)
<High School	2.57	1.36	4.84	<.01	1.97	1.02	3.79	<.01	2.51	1.33	4.74	<.01	2.22	1.17	4.24	.02	2.18	1.14	4.15	.02
>High School	0.35	0.22	0.56	<.01	0.37	0.23	0.61	<.01	0.37	0.23	0.59	<.01	0.35	0.21	0.56	<.01	0.37	0.23	0.60	<.01
Difficulty with written information (SILS) (reference = rarely/never)
Always/often/Sometimes					3.14	1.75	5.65	<.01
Confidence filling out medical forms (SILS) (reference = quite a bit/extremely confident)
Not at all/a little bit/somewhat									1.35	0.87	2.12	.19
Help reading hospital materials (SILS) (reference = rarely/never)
Always/often/sometimes													1.94	1.18	3.18	.01
BHLS																	0.88	0.81	0.96	<.01
Goodness of fit statistics
R²	0.342				0.375				0.346				0.357				0.361
AIC	505.02				491.46				505.27				500.08				498.07
AUROC	0.794				0.812				0.800				0.803				0.809

↵* For 95% confidence interval (CI) values, the lower limit is set on the left and the upper limit is on the right.
AIC, Akaike information criterion; AUROC, area under the receiver operator characteristics curve; BHLS, Brief Health Literacy Screen; OR, odds ratio; SILS, Single Item Literacy Screener.

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Table 3. Logistic Regression Models Estimating Limited Health Literacy against the Newest Vital Sign

Model	Demographics Only				SILS												BHLS
Model	Demographics Only				Difficulty with Written Information				Confidence Filling out Medical Forms				Help Reading Hospital Materials				BHLS
Predictors	OR	95% CI^*		P value	OR	95% CI^*		P value	OR	95% CI^*		P value	OR	95% CI^*		P value	OR	95% CI^*		P value
Age	1.02	1.01	1.04	<.01	1.02	1.01	1.04	.01	1.02	1.01	1.04	<.01	1.02	1.01	1.04	<.01	1.02	1.01	1.04	.01
Sex (reference = male)
Female	0.93	0.60	1.44	.75	0.95	0.61	1.48	.83	0.92	0.60	1.43	.72	0.96	0.62	1.49	.85	0.94	0.06	1.46	.79
Race (reference = white)
Black	3.51	2.27	5.43	<.01	3.50	2.25	5.45	<.01	3.41	2.20	5.28	<.01	3.41	2.20	5.29	<.01	3.33	2.14	5.18	<.01
Education (reference = high school)
<High school	2.06	1.03	4.13	0.04	1.68	0.82	3.44	.15	1.97	0.98	3.97	.06	1.84	0.97	3.73	.06	1.75	0.86	3.57	.12
>High school	0.40	0.25	0.62	<.01	0.43	0.27	0.67	<.01	0.42	0.27	0.67	<.01	0.41	0.26	0.64	<.01	0.44	0.28	0.67	<.01
Difficulty with written information (SILS) (reference = rarely/never)
Always/often/sometimes					2.86	1.50	5.46	<.01
Confidence filling out medical forms (SILS) (reference = quite a bit/extremely confident)
Not at all/a little bit/ somewhat									1.61	1.03	2.52	.04
Help reading hospital materials (SILS) (reference = rarely/never)
Always/often/sometimes													1.80	1.08	3.00	.02
BHLS																	0.85	0.78	.94	<.01
Goodness of fit statistics
R²	0.203				0.232				0.214				0.216				0.235
AIC	534.75				525.27				532.29				531.46				524.15
AUROC	0.734				0.749				0.738				0.741				0.749

↵* For 95% confidence interval (CI) values, the lower limit is set on the left and the upper limit is on the right.
AIC, Akaike information criterion; AUROC, area under the receiver operator characteristics curve; BHLS, Brief Health Literacy Screen; OR, odds ratio; SILS, Single Item Literacy Screener.

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Table 4. Comparison of Single-Item Literacy Screener/Brief Health Literacy Screen (SILS/BHLS) Model Identification of Limited Health Literacy With Objective Health Literacy Measures (Rapid Estimate of Adult Literacy in Medicine, Revised, and Newest Vital Sign^*)

Models^*	Limited Health Literacy n (%)		Adequate Health Literacy n (%)		Kappa	95% CI	Misclassified (%)	Sensitivity	Specificity	Positive Likelihood Ratio	Negative Likelihood Ratio
Difficulty with written information (SILS) and demographics model^*
REALM-R limited health literacy	132	62.0	81	38.0	0.43	0.35–0.51	28.1	0.62	0.81	3.26	0.47
REALM-R adequate health literacy	47	19.4	195	80.6
NVS limited health literacy	233	81.5	53	18.5	0.49	0.41–0.57	23.7	0.82	0.68	2.56	0.26
NVS adequate health literacy	55	32.5	114	67.5
Brief Health Literacy Screen and demographics model^*
REALM-R limited health literacy	171	80.3	42	19.7	0.42	0.34–0.50	29.5	0.80	0.62	2.11	0.32
REALM-R adequate health literacy	92	38.0	150	62.0
NVS limited health literacy	221	77.3	65	22.7	0.48	0.40–0.56	24.8	0.77	0.72	2.75	0.32
NVS adequate health literacy	48	28.4	121	71.6