Associations Between Health Literacy and Medication Self-Management Among Community Health Center Patients with Uncontrolled Hypertension

Figures & data

Table 1 Participant Characteristics Overall and Stratified by Health Literacy

	Total (N = 919)	Health Literacy			P-value
		Likely Limited (N = 436)	Possibly Limited (N = 305)	Adequate (N = 178)
Age, Mean (SD) in years	52.3 (9.7)	54.1 (9.6)	51.4 (9.4)	49.4 (9.7)	<0.001
Female, n (%)	624 (67.9)	294 (67.4)	199 (62.3)	131 (73.6)	0.16
Race/Ethnicity, n (%)
Black	800 (87.1)	404 (92.7)	260 (85.3)	136 (76.4)	<0.001
White	32 (3.5)	3 (0.7)	15 (4.9)	14 (7.9)
Hispanic	45 (4.9)	10 (2.3)	19 (6.2)	16 (9.0)
Other/Refused	42 (4.6)	19 (4.4)	11 (3.6)	12 (6.7)
Education, n (%)
Less than Grade 12	295 (32.1)	198 (45.4)	78 (25.6)	19 (10.7)	<0.001
Grade 12 or GED	324 (35.3)	153 (35.1)	119 (39.0)	52 (29.2)
College 1 year to 3 years	253 (27.5)	76 (17.4)	92 (30.2)	85 (47.8)
College 4 years or more	46 (5.0)	8 (1.8)	16 (5.3)	22 (12.4)
Refused	1 (0.1)	1 (0.2)	0 (0)	0 (0)
Income, n (%)
$9999 or less	438 (47.7)	225 (51.6)	152 (49.8)	61 (34.3)	<0.001
$10,000 - $19,999	247 (26.9)	117 (26.8)	72 (23.6)	58 (32.6)
$20,000 or more	161 (17.5)	42 (9.6)	64 (21.0)	55 (30.9)
Refused	73 (7.9)	52 (11.9)	17 (5.6)	4 (2.3)
Insurance
Medicaid	463 (50.4)	221 (50.7)	155 (50.8)	87 (48.9)	0.90
Medicare	184 (20.0)	98 (22.5)	59 (19.3)	27 (15.2)	0.11
Private/Managed Care	100 (10.9)	47 (10.8)	35 (11.5)	18 (10.1)	0.89
Self-pay/Other/Refused	163 (17.7)	78 (17.9)	51 (16.7)	34 (19.1)	0.80
English speaker, n (%)	890 (96.8)	425 (97.5)	293 (96.1)	172 (96.6)	0.55
Marital Status, n (%)
Married/Partner	191 (20.8)	82 (18.8)	66 (21.6)	43 (24.2)	0.30
Not Married	728 (79.2)	354 (81.2)	239 (78.4)	135 (75.8)
N of self-reported medications, Median (IQR)	5 (4, 6)	5 (4, 6)	5 (4, 6)	4 (3, 6)	0.24
Diabetes mellitus, n (%)	393 (42.8)	186 (42.7)	135 (44.3)	72 (40.5)	0.71
Enrollment blood pressure, Mean (SD) in mm Hg
Systolic	145.5 (17.4)	145.3 (16.7)	146.1 (18.2)	144.8 (17.8)	0.65
Diastolic	88.7 (12.1)	87.6 (12.2)	90.0 (11.8)	89.3 (12.2)	0.08

Abbreviations: SD, standard deviation; GED, General Educational Development; IQR, interquartile range.

Table 2 Medication Self-Management Outcomes by Health Literacy*

	Likely Limited		Possibly Limited		Adequate		P-value
	n/N	%	n/N	%	n/N	%
Medications reconciled
Hypertension	164/433	37.9	140/302	46.4	90/176	51.1	0.005
All chronic condition medications	78/433	18.0	62/302	20.5	52/176	29.6	0.007
All medications	28/433	6.5	26/302	8.6	21/176	11.9	0.081
Knowledge of medication indication
Hypertension	281/369	76.2	212/269	78.8	149/168	88.7	0.003
All chronic condition medications	264/412	64.1	202/292	69.2	147/177	83.1	<0.001
All medications	171/436	39.2	148/305	48.5	116/178	65.2	<0.001
Understanding of medication instructions and dosing
Hypertension	283/365	77.5	220/266	82.7	146/166	88.0	0.013
All chronic condition medications	275/404	68.1	208/288	72.2	145/175	82.9	0.001
All medications	251/430	58.4	199/302	65.9	135/178	75.8	<0.001
Medication adherence, 4-day recall
Hypertension	242/369	65.6	170/269	63.2	94/168	56.0	0.010
All chronic condition medications	232/411	56.5	155/291	53.3	81/176	46.0	0.069

Note: *Numbers do not always equal total number of participants in each health literacy category in cases where no ACCESS record was available (medication reconciliation), no patient-reported medications could be identified in the medication category, dosing instructions were not available, or due to non-response.

Table 3 Adjusted Relationships of Medication Self-Management Outcomes by Health Literacy*

	Likely Limited vs Adequate		Possibly Limited vs Adequate		Likely Limited vs Possibly Limited
	Adjusted Odd Ratio (CI)	P	Adjusted Odd Ratio (CI)	P	Adjusted Odd Ratio (CI)	P
Medications reconciled
Hypertension	0.72 (0.49, 1.06)	0.094	0.94 (0.64, 1.38)	0.74	0.77 (0.56, 1.05)	0.10
All chronic condition medications	0.79 (0.50, 1.25)	0.32	0.74 (0.47, 1.16)	0.18	1.07 (0.72, 1.60)	0.73
All medications	0.69 (0.35, 1.36)	0.28	0.80 (0.42, 1.51)	0.49	0.87 (0.48, 1.56)	0.63
Knowledge of medication indication
Hypertension	0.51 (0.29, 0.90)	0.020	0.54 (0.31, 0.96)	0.037	0.94 (0.63, 1.40)	0.76
All chronic condition medications	0.48 (0.30, 0.77)	0.0025	0.54 (0.33, 0.87)	0.012	0.89 (0.64, 1.25)	0.51
All medications	0.37(0.25, 0.54)	<0.0001	0.53 (0.36, 0.79)	0.0017	0.69 (0.51, 0.94)	0.019
Understanding of medication instructions and dosing
Hypertension	0.53 (0.31, 0.91)	0.021	0.72 (0.40, 1.27)	0.25	0.74 (0.49 1.11)	0.14
All chronic condition medications	0.47 (0.29, 0.74)	0.001	0.57 (0.35, 0.92)	0.022	0.82 (0.58, 1.16)	0.26
All medications	0.44 (0.29, 0.68)	0.0002	0.63 (0.40, 0.97)	0.038	0.70 (0.51, 0.97)	0.034
Medication adherence, 4-day recall
Hypertension	1.38 (0.93, 2.05)	0.11	1.29 (0.86, 1.92)	0.22	1.08 (0.77, 1.51)	0.67
All chronic condition medications	1.47 (1.00, 2.16)	0.051	1.31 (0.89, 1.93)	0.17	1.12 (0.82, 1.54)	0.47

Notes: *Numbers do not always equal total number of participants in each arm in cases where no ACCESS record was available (medication reconciliation), no patient-reported medications could not be identified in the category, or due to non-response. CI: 95% confidence interval. All models use adequate health literacy category as the reference group. Models include age, sex, and number of medication as fixed effects and health center as random effects.