The Association Among Medication Beliefs, Perception of Illness and Medication Adherence in Ischemic Stroke Patients: A Cross-Sectional Study in China

Figures & data

Table 1 Characteristics of Ischemic Stroke Patients

Characteristics	Total n= 306	Adherent* n= 86	Non-Adherent* n= 220	P
Age, years, median (IQR)	63.47±10.20	62.72±9.67	63.77±10.41	0.420
Sex, no. (%)
Men	177(57.8)	49(16)	128(41.8)	0.848
Woman	129(42.2)	37(12.1)	92(30.1)
NIHSS, no. (%)
Mild to moderate^††	273(89.2)	82(26.8)	191(62.4)	0.031
Mild Impairment^†	33(10.8)	4(1.3)	29(9.5)
Education, no. (%)
Literacy	33(10.8)	5(1.6)	28(9.2)	0.079
Primary school	86(28.1)	25(8.2)	61(19.9)
Middle School	111(36.3)	35(11.4)	76(24.8)
High school, college	51(16.7)	10(3.3)	41(13.4)
University or above	25(8.2)	11(3.6)	14(4.6)
Duration of disease, no. (%)
< 1 year	104(34)	23(7.5)	81(26.5)	0.181
1–5 years	107(35)	29(9.5)	78(25.5)
> 5 year	79(25.8)	29(9.5)	50(16.3)
Unknown	16(5.2)	5(1.6)	11(3.6)
Occupation, no. (%)
Farmer	63(20.6)	16(5.2)	47(15.4)	0.910
Worker	90(29.4)	26(8.5)	64(20.9)
Housewife, unemployment	25(8.2)	6(2)	19(6.2)
Retirement	69(22.5)	21(6.9)	48(15.7)
Healthcare professional	6(2)	2(0.7)	4(1.3)
Civil service	15(4.9)	3(1)	12(3.9)
Teacher	7(2.3)	1(0.3)	6(2)
Other	31(10.1)	11(3.6)	20(6.5)
Payment methods, no. (%)
Self-supporting commercial	32(10.5)	8(2.6)	24(7.8)	0.357
A new rural cooperative medical system	94(30.7)	21(6.9)	73(23.9)
Urban medical insurance	149(48.7)	50(16.3)	99(32.4)
Commercial medical insurance	5(1.6)	1(0.3)	4(1.3)
Other	26(8.5)	6(2)	20(6.5)

Notes: *Used MARS scores 20 as the cut-off point. ^†NIHSS scores ≤ 4. ^††NIHSS scores 5–14.

Abbreviations: NIHSS, The National Institute of Health Stroke Scale.

Table 2 An Unadjusted Comparison of the Perception of Illness and Medication Beliefs According to Medication Adherence

Perception of Illness and Medication Beliefs	Adherent Mean (SD)	Non-Adherent Mean (SD)	Cohen’s d	P
Brief Illness Perception Questionnaire (BIPQ)^#Consequences
How much does your ischemic stroke affect your life?	6.58 (2.64)	8.14 (2.41)	0.62	0.000
Timeline
How long do you think your ischemic stroke will continue?	6.62 (2.78)	7.69 (2.47)	0.41	0.001
Personal control
How much control do you feel you have over your ischemic stroke symptoms?	4.84 (2.60)	5.28 (2.92)	0.16	0.218
Treatment control
How much do you think your treatment can prevent your ischemic stroke?	6.91 (2.03)	6.95 (2.48)	0.02	0.863
Identity
How much do you experience symptoms from your ischemic stroke?	6.29 (2.16)	7.61 (2.3)	0.60	0.000
Emotional Representation (concern)
How concerned are you about your ischemic stroke?	6.99 (2.64)	7.94 (2.36)	0.38	0.002
Emotional Representation (emotions)
How much does your ischemic stroke affect you emotionally?	6.67 (2.52)	7.86 (2.47)	0.48	0.000
Comprehensibility
How much do you think you know about ischemic stroke?	5.23 (2.80)	5.10 (2.79)	0.05	0.719
Beliefs about medicines questionnaire (BMQ)
Specific Necessity*	3.58 (0.80)	3.68 (0.84)	0.12	0.344
Specific Concern**	3.05 (0.73)	3.57 (0.89)	0.64	0.000
General Overuse***	2.88 (0.86)	3.33 (0.91)	0.51	0.000
General Harm****	2.93 (0.78)	3.31 (0.92)	0.45	0.000

Notes: ^#Each item scored on a scale of 0–10. *Possible mean scores 1–5; a higher score indicates a greater belief that ischemic stroke medications are necessary. **Possible mean scores 1–5; a higher score indicates a greater worry about ischemic stroke medications. ***Possible mean scores 1–5; a higher score indicates a greater belief that doctors overuse or put too much trust in medicines. ****Possible mean scores 1–5; a higher score indicates a greater belief that ischemic stroke medications are harmful.

Table 3 Adjusted Comparison of Perception of Illness and Medication Beliefs According to Medication Adherence

	MODEL 1
	B	S.E.	Wald	P	OR	95% C.I.
BMQ
Specific Necessity	−0.065	0.165	0.155	0.694	0.937	0.678 to 1.296
Specific Concern	−0.555	0.178	9.745	0.002	0.574	0.405 to 0.813
General Overuse	−0.256	0.181	1.994	0.158	0.774	0.543 to 1.104
General Harm	−0.184	0.180	1.053	0.305	0.832	0.585 to 1.183
	MODEL 2
	B	S.E.	Wald	P	OR	95% C.I.
BIPQ (overall score)	−0.036	0.011	10.956	0.001	0.964	0.944 to 0.985
	MODEL 3
	B	S.E.	Wald	P	OR	95% C.I.
BMQ
Specific Necessity	−0.165	0.198	0.695	0.405	0.848	0.575 to 1.250
Specific Concern	−0.427	0.211	4.079	0.043	0.652	0.431 to 0.987
General Overuse	−0.249	0.219	1.292	0.256	0.780	0.508 to 1.197
General Harm	−0.298	0.219	1.853	0.173	0.742	0.484 to 1.140
BIPQ
Consequences	−0.103	0.087	1.401	0.237	0.902	0.761 to 1.070
Timeline	−0.011	0.075	0.022	0.881	0.989	0.854 to 1.145
Personal control	0.086	0.067	1.630	0.202	1.089	0.955 to 1.242
Treatment control	−0.110	0.086	1.660	0.198	0.895	0.757 to 1.059
Identity	−0.162	0.104	2.441	0.118	0.850	0.693 to 1.042
Emotional Representation (concern)	0.040	0.104	0.148	0.700	1.041	0.849 to 1.277
Emotional Representation (emotions)	−0.025	0.110	0.051	0.821	0.975	0.786 to 1.210
Comprehensibility	−0.060	0.064	0.861	0.353	0.942	0.831 to 1.069

Notes: Model 1: Adjusted for medication belief. Model 2: Adjusted for the perception of illness (overall score) and age, sex, NIHSS, education, occupation, duration of disease, and payment methods. Model 3: Adjusted for model 1 and each of the domains of the perception of illness, and age, sex, NIHSS, education, occupation, duration of disease, and payment methods.

Abbreviations: BMQ, Beliefs about Medicines Questionnaire; BIPQ, Brief Illness Perception Questionnaire.

Table 4 Correlation Matrix for the Different Scales Used to Test BMQ, BIPQ, and MARS. Pearson Correlation Coefficient (p-value)

	1	2	3	4	5	6
1. Specific Necessity	1
2. Specific Concern	0.147*	1
3. General Overuse	0.188**	0.438**	1
4. General Harm	−0.058	0.382**	0.492**	1
5. BIPQ (overall score)	0.050	0.305**	0.215**	0.174**	1
6. MARS	−0.069	−0.317**	−0.404**	−0.368**	−0.278**	1

Notes: 1–4: Beliefs about Medicines Questionnaire (BMQ) dimensions 1 to 4. **Correlation is significant at the 0.01 level (2-tailed). *Correlation is significant at the 0.05 level (2-tailed).

Abbreviations: BIPQ, Brief Illness Perception Questionnaire; MARS: Medication Adherence Self Report Scale.

Table 5 The Effect of Medication Belief Mediators (M) in the Association Between the Perception of Illness (X) and Medication Adherence (Y)

BMQ (M)	BIPQ (X)
	Total (c)			X → M (a)			M → Y (b)			X → Y (c’)			Indirect effect (a*b)
	c	SE	P	a	SE	P	b	SE	P	c’	SE	P	a*b	95% Cl
Specific Necessity	−0.086	0.021	0.000	0.002	0.004	0.5605	−0.365	0.331	0.271	−0.085	0.021	0.0001	−0.001	−0.005 to 0.003
Specific Concern				0.019	0.004	0.0000	−1.418	0.316	0.000	−0.058	0.021	0.0057	−0.027	−0.044 to −0.014
General Overuse				0.014	0.004	0.0007	−1.957	0.281	0.000	−0.059	0.020	0.0026	−0.026	−0.044 to −0.011
General Harm				0.009	0.004	0.0174	−1.841	0.291	0.000	−0.069	0.020	0.0005	−0.017	−0.034 to −0.003

Notes: All analyses were performed separately according to each medication belief mediator. Data adjusted by age, sex, The National Institute of Health Stroke Scale (NIHSS), education, occupation, duration of disease, and payment methods.

Abbreviations: BMQ, Beliefs about Medicines Questionnaire; BIPQ, Brief Illness Perception Questionnaire; M, Medication belief mediators; X, The perception of illness; Y, Medication adherence.

Figure 1 The effect of medication belief mediators (M) in the association between the perception of illness (X) and medication adherence (Y).

Note: Coefficients were adjusted for age, sex, The National Institute of Health Stroke Scale (NIHSS), education, occupation, duration of disease, and payment methods using the bootstrapping method. ^aP < 0.05; ^bP < 0.01; ^cP < 0.001. c’, a direct effect of X on Y.