Antihypertensive Medication Adherence and Associated Factors: A Cross-Sectional Analysis of Patients Attending a National Referral Hospital in Asmara, Eritrea

Figures & data

Table 1 Knowledge About Hypertension (n=335)

Questions Related to Knowledge About Hypertension	Pooled (Yes) N (%)	Men (Yes) N (%)	Women (Yes) N (%)	Chi-square χ^2	P-value
1) HTN can be controlled if patients accept it and adhere to treatment?	284 (84.8)	106 (37.3)	178 (62.7)	10.77	<0.001
2) HTN can cause heart attack	122 (36.4)	58 (47.5)	64 (52.5)	18.843	<0.001
3) Is it true that HTN runs in families?	195 (58.5)	75 (38.5)	120 (61.5)	4.67	0.020
4) Retinopathy	132 (39.4)	52 (39.4)	80 (60.6)	3.125	0.050
5) Heart problems	267 (79.7)	72 (27.0)	195 (73.0)	26.93	<0.001
6) HTN is can cause kidney problems	131 (39.1)	60 (45.8)	71 (54.2)	14.02	<0.001
7) HTN can cause sudden death	197 (59.2)	47 (23.9)	150 (76.1)	21.844	<0.001
8) HTN can cause stroke	301 (89.9)	99 (32.9)	202 (67.1)	3.434	0.180
9) Regular physical exercise may help control HTN?	110 (32.8)	54 (49.1)	56 (50.9)	17.285	<0.001
10 Can eating salty food increase the risk of HBP?	92 (27.5)	37 (40.2)	55 (59.8)	2.387	0.079
11) Can stress cause HBP	292 (87.2)	92 (31.5)	200 (68.5)	5.036	0.021
12) Obesity can cause hypertension	100 (29.9)	41 (41.0)	59 (59.0)	3.279	0.047
13) Can cigarette smoking cause HTN?	96 (28.7)	38 (39.6)	58 (60.4)	2.062	0.096
14) Can heavy alcohol consumption cause HTN	118 (35.3)	40 (33.9)	78 (66.1)	0.000	0.539

Table 2 Patients Characteristics

Variables	Categories	Total N (%)	Males n (%)	Females n (%)	P-value Chi-Square
Age
	≤40 Years	17 (5.1)	8(47.1)	9(52.9)	< 0.001 (15.52)
	41–60 Years	152 (45.4)	66(43.4)	86(56.6)
	>60 Years	166 (49.6)	39(23.5)	127(76.5)
Duration of HTN
	<5 Years	109 (32.5)	39(35.8)	70(64.2)	0.690 (1.47)
	6–10 Years	136 (40.6)	44(32.4)	92(67.6)
	11–15 Years	26 (7.8)	7(26.9)	19(73.1)
	>16 Years	54 (16.1)	21(38.9)	33(61.1)
Educational Level
	No formal education	102 (30.4)	11(10.8)	91(89.2)	< 0.001 (35.41)
	Primary level	140 (41.8)	58(41.4)	82(58.6)
	Secondary and above	93 (27.8)	44(47.3)	49(52.7)
Marital Status
	Single/separated/divorced/widowed	149 (44.5)	39(26.2)	110(73.8)	0.010 (6.86)
	Currently married/Cohabitating	186 (55.5)	74(39.8)	112(60.2)
Ethnicity
	Tigrigna	318 (94.9)	109(34.4)	209(65.7)	0.439 0.834
	Others	17 (5.1)	4(23.5)	13(76.5)
Employment Status
	Unemployed	41 (12.2)	74(60.7)	48(39.3)	<0.001 137.95
	Government/NGO	122 (36.4)	24(77.4)	7(22.6)
	Self-employed	31 (9.3)	0 (0.0)	141(100)
	Housewife	141 (42.1)	15(36.6)	26(63.4)
Tobacco Use
	Yes	12 (3.6)	11(91.7)	1(8.3)	< 0.001 (18.69)
	No	323 (96.4)	102(31.6)	221(68.4)
Coffee Consumption
	Daily/Frequently	123 (36.7)	34(27.6)	89(72.4)	0.093 (3.22)
	Rarely/Never	212 (63.3)	79(37.3)	133(62.7)
Alcohol Consumption
	Yes	71(21.2)	31(43.7)	40(56.3)	0.049 (3.98)
	No	264(78.8)	82(31.1)	182(68.9)
Diabetes
	Yes	30 (9.0)	18(60.0)	12(40.0)	0.002 (10.17)
	No	305 (91.0)	95(31.1)	210(68.9)
Number of Tablets
	1	94 (41.6)	17(18.1)	77(81.9)	0.046 (8.0)
	2	126 (55.8)	39(31.0)	87(69.0)
	≥3	6 (1.8)	3(50.0)	3(50.0)
Physical Exercise
	Daily	18(5.4)	11(61.1)	7(38.9)	<0.001 26.99
	Frequently	7(2.1)	6(85.7)	1(14.3)
	Rarely	38(11.3)	21(55.3)	17(44.7)
	Never	272(81.2)	75(27.6)	197(72.4)
HTN Complications
	Yes	125 (37.3)	52(41.6)	73(58.4)	0.023 (5.52)
	No	210 (62.7	61(29.0)	149(71.0)
Systolic BP
	<140 mmHg	166(49.6)	48(28.9)	118(71.1)	0.083 (3.41)
	>140 mmHg	169(50.4)	65(38.5)	104(61.5)
Diastolic BP
	<90 mmHg	187(56.0)	56(29.9)	131(70.1)	0.103 (2.87)
	>90 mmHg	147(44.0)	57(38.8)	90(61.2)
BP Control
	Good	160(47.9)	47(29.4)	113(70.6)	0.106 (2.73)
	Poor	174(52.1)	66(37.9)	108(62.1)
Stage of Hypertension
	Stage 1	143(42.7)	59(41.3)	84(58.7)	0.015 (10.51)
	Stage 2	83(24.8)	29(34.9)	54(65.1)
	Stage 3	33(9.9)	10(30.3)	23(69.7)
	Controlled BP	76(22.7)	15(19.7)	61(80.3)

Notes: Underweight = BMI ≤18:5 kg/m²; normal weight = BMI: 18.6–24.9 kg/m²; oerweight = BMI: 25–29.9 kg/m²; obese ≥30 kg/m². Abdominal obesity: waist circumference (WC) >94 cm in men and WC >80 cm in women.

Abbreviations: HTN, hypertension; BMI, body mass index; BP, blood pressure; NGO, non-governmental organisation.

Table 3 Responses to MARS Scale Questions

No.	MARS Scale Questions*	Yes, N(%)	No, N(%)
1	Do you ever forget to take your high blood pressure pills?	187(55.83)	148(44.2)
2	Are you careless at times about taking your medication?	137 (40.9)	198(59.1)
3	When you feel better, do you sometimes stop taking your medication?	186(55.5)	149(44.5)
4	Sometimes if you feel worse when you take the medication, do you stop taking it?	174(51.9)	161(48.1)
5	When you feel like your symptoms are under control, do you sometimes stop taking your medicine?	132(39.4)	203(60.6)
6	Do you stop taking your medicine because you fear negative Side-effects?	49(14.6)	286(85.4)
7	Have you ever reduced, or stopped taking your medicine, without informing your doctor, because you felt worse when you took it?	172(51.4)	1873(55.6)
8	Have you ever taken one or more hypertension tablets on your own initiative after having felt worse?	160(47.8)	175(52.2)
9	Have you ever discontinued HTN therapy because your medication ran out	159(47.5)	176(52.5)
10	When you travel or leave home, do you sometimes forget to take with you your high blood pressure medicine?	148(44)	182(56.0)

Notes: *MARS Scale questions are adapted (with modifications) from: Thompson K, Kulkarni J, Sergejew AA. Reliability and validity of a new Medication Adherence Rating Scale (MARS) for the psychoses. Schizophr Res. 2000;42(3):241–247. doi:10.1016/s0920-9964(99)00130–9.¹⁴ Copyright © 2000 Elsevier Science B.V. All rights reserved. With permission from Elsevier.

Table 4 Factors Associated with Adherence to Antihypertensive Medications (N=335)

Population Characteristics	Antihypertensive Medications Adherence		Adherence vs Non-Adherence
	Poor (%)	Good (%)	COR(95% CI)	P value	AOR(95% CI)	P value
Gender
Male	91 (80.5)	22 (19.5)	10.55(2.42–45.97)	0.002	4.95(1.52–16.11)	0.008
Female	153 (68.9)	69 (31.1)	1		1	-
Age
<40 years	9 (52.9)	8 (47.1)	0.34(0.06–2.00)	0.234	-	-
41–60 years	122 (80.3)	30(19.7)	1.11(0.47–2.63)	0.816	-	-
>61 years	113 (68.1)	53 (31.9)	1	0.385	-	-
Educational Status
No Education	61 (59.8)	41 (40.2)	1	0.426	-	-
Primary level	108(77.1)	32 (22.9)	1.21(0.54–2.74)	0.642	-	-
Secondary and above	75 (80.6)*	18 (19.4)	1.93(0.71–5.29)	0.200	-	-
Marital Status
Single/Widow/Divorced	109 (73.2)	40 (26.8)	1.4(0.669–2.93)	0.372	-	-
Married	135 (72.6)	51 (27.4)	1		–
Employment Status
Employed/NGO	101(82.8)	21 (17.2)	1	0.01	1	0.002
Self-employed	28 (90.3)	3 (9.7)	1.57(0.32–7.78)	0.578	1.95(0.45–8.48)	0.373
Housewife	77 (54.6)	64 (45.4)	0.10(0.02–0.51)	0.005	0.13(0.04–0.413)	0.001
Unemployed	38 (92.7)*	3 (7.3)	1.70(0.32–9.15)	0.537	1.38(0.32–5.98)	0.670
Duration of HTN
<5 years	73(67.0)	36(33.0)	1	0.002	-	-
6–10 years	115(84.6)	21(15.4)	4.02(1.72–9.41)	0.001	-	-
11–15 years	14(53.8)	12(46.2)	0.50(0.15–1.67)	0.262	-	-
>16 years	37(68.5)	17(31.5)	1.60(0.61–4.15)	0.337	-	-
Attendance of Health Talk at the Clinic
Yes	110(82.7)	23(17.3)	1		1
No	134(68.7)	61(31.3)	2.38(1.16–4.88)	0.018	2.33(1.17–4.63)	0.016
Complication of HTN are Dangerous
Yes	192(68.1)	90(31.9)	NE	-	-	-
No	52(98.1)	1(1.9)	NE	-		-
Suffered Serious HTN Complication
	90(84.1)	17(15.9)	NE
	154(67.5)	74(32.5)	NE
High Cost of Medication					-	-
Yes	178(99.4)	1(0.6)	NE	-	-	-
No	66(42.3)	90(57.7)	NE	-	-	-
Cost of Transport to Hospital is high
Yes	128(64.3)	71(35.7)	6.24(2.86–13.61)	<0.001	6.87(3.25–14.52)	<0.001
No	116(85.3)	20(14.7)	1		1
Family Members Support
Yes	220(72.6)	83 (27.4)	0.63(0.21–1.91)	0.410	-	-
No	24 (75.0)	8 (25.0)	1		-	-
Knowledge
Good	163(66.3)	83(33.7)	1	<0.001	1
Poor	77(91.7)	7(8.3)	13.8(3.26–58.01)		6.23(2.36–18.05)	<0.001
Classes of Raised BP
Stage 1	109(76.2)	34(23.8)	1.70(0.74–3.92)	0.211	1.63(0.74–3.62)	0.228
Stage 2	62(74.7)	21(25.3)	1.88(0.74–4.79)	0.187	1.72(0.70–4.24)	0.239
Stage 3	27(81.8)	6(18.2)	5.89(1.47–23.49)	0.012	5.55(1.44–21.37)	0.013
Controlled BP	46(60.5)	30(39.5)	1	0.86	1	0.094

Notes: Bold values: P value <0.05. *indicates linear by linear association. Variable(s) entered on step 1: sex, age, educational status, marital status, employment status, duration of HTN, attendance of health talk at the clinic, family members support, knowledge, classes of raised BP. Complication of HTN are serious, suffered serious HTN complication, high cost of medication were not incorporated in the models due to a number of considerations including presence of collinearity issues. Suffered serious HTN complications: stroke, myocardial infarction, peri-arterial disease.

Abbreviations: BP, blood pressure; HTN, hypertension; NGO, non-governmental organization; AOR, adjusted odds ratio; COR, crude odds ratio; CI, confidence interval; NE, not entered.

Thompson K, Kulkarni J, Sergejew AA. Reliability and validity of a new Medication Adherence Rating Scale (Mars) for the psychoses. Schizophr Res. 2000;42(3):241–247. doi:10.1016/s0920-9964(99)00130-9

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