Factors related to intentional and unintentional medication nonadherence in elderly patients with hypertension in rural community

Figures & data

Figure 1 Framework of current study.

Abbreviation: BMQ, beliefs about medicines questionnaire.

Table 1 General characteristics and medication adherence

Characteristic	Medication adherence status			P-valuea
	Adherence	Nonadherence
		Unintentional	Intentional
Age (years)	75.3±8.6	74.4±8.5	73.2±8.6	0.110
Gender				0.132
Male	41 (41.8)	22 (22.4)	35 (35.7)
Female	141 (46.5)	85 (28.1)	77 (25.4)
Educational level				0.056
≤ Primary school	159 (47.5)	92 (27.5)	84 (25.1)
Middle school	16 (39.0)	9 (22.0)	16 (39.0)
≥ High school	7 (28.0)	6 (24.0)	12 (48.0)
Income				0.038
<1 million KRW	156 (47.1)	93 (28.1)	82 (24.8)
1–2 million KRW	19 (40.4)	9 (19.1)	19 (40.4)
≥2 million KRW	7 (30.4)	5 (21.7)	11 (47.8)
Spouse				0.426
Yes	80 (42.6)	50 (26.6)	58 (30.9)
No	102 (47.9)	57 (26.8)	54 (25.4)
Duration	9.2±6.8	8.7±8.1	7.8±6.3	0.275
Drug count	3.0±2.1	3.4±1.9	2.9±1.7	0.072
Medication frequency				0.676
Once a day	169 (46.0)	101 (27.5)	97 (26.4)
Twice a day	13 (38.2)	10 (29.4)	11 (32.4)
Comorbidity				0.958
Yes	104 (45.4)	60 (26.2)	65 (28.4)
No	78 (45.3)	47 (27.3)	47 (27.3)
Self-rated health				0.089
Good	31 (53.4)	10 (17.2)	17 (29.3)
Normal	60 (37.7)	49 (30.8)	50 (31.4)
Bad	91 (49.5)	48 (26.1)	45 (24.5)
Total	182 (45.4)	107 (26.7)	112 (27.9)

Notes: Values are presented as mean ± SD or n (%) unless otherwise indicated.

a Calculated by chi-square test or analysis of variance.

Abbreviations: SD, standard deviation; KRW, Korean Won.

Table 2 Beliefs about medication questionnaire (BMQ) and medication adherence

Individual cognitive factors	Medication adherence status			P-valuea
	Adherent (A)	Nonadherent
		Unintentional (B)	Intentional (C)
BMQ (necessity)	17.0±4.1	16.8±3.3	15.3±3.6	0.001 (A, B) (C)
BMQ (concerns)	12.2±3.5	12.6±2.9	12.6±3.2	0.441
Self-efficacy	42.3±8.2	37.9±7.3	36.1±8.4	<0.001 (A) (B, C)

Notes: Values are presented as mean ± SD unless otherwise indicated.

a Calculated by analysis of variance (Tukey multiple comparison).

Abbreviations: BMQ, beliefs about medicines questionnaire; SD, standard deviation.

Figure 2 Blood pressure according to medication adherence groups. Left is systolic blood pressure and right is diastolic blood pressure.

Note: *P<0.05.

Table 3 Relationship between blood pressure control and medication adherence

Medication adherence	Blood pressure controlleda		P-valueb	P-trendc
	No	Yes
Adherence	78 (42.9%)	104 (57.1%)	0.751	0.466
Unintentional nonadherence	47 (43.9%)	60 (56.1%)
Intentional nonadherence	53 (47.3%)	59 (52.7%)

Notes: Values are presented as n (%) unless otherwise indicated.

a Systolic blood pressure <140 mmHg and diastolic blood pressure <90 mmHg;

b chi-square test;

c chi-square test for trend.

Table 4 Health behaviors according to medication adherence

Medication adherence	Health behaviora
	Male		Female
	Regression coefficientb	P-value	Regression coefficientb	P-value
Adherence (reference)	–	–	–	–
Unintentional nonadherence	−0.476	0.692	−0.237	0.412
Intentional nonadherence	0.126	0.824	−1.399	0.036

Notes:

a Including low-salt diet, low-fat diet, regular exercise, networking, smoking, and drinking.

b Adjusted for age, education, income, spouse, drug count, medication frequency, comorbidity, duration of hypertension, and self-rated health. The dash indicates no data.

Table 5 Multiple regression of BMQ and self-efficacy

Predisposing factors	Necessity			Concerns			Self-efficacy
	Unstandardized coefficients		P-value	Unstandardized coefficients		P-value	Unstandardized coefficients		P-value
	B	SE		B	SE		B	SE
Age (years)	−0.028	0.026	0.279	−0.030	0.022	0.166	0.005	0.057	0.926
Gender (female/male)	0.532	0.517	0.304	0.275	0.442	0.533	0.944	1.149	0.412
Educational level (reference: ≤ primary school)
Middle school	0.454	0.706	0.520	−0.729	0.604	0.228	0.128	1.570	0.935
≥ High school	−0.814	0.941	0.388	0.270	0.805	0.738	1.980	2.093	0.345
Income (reference: <1 million KRW)
1–2 million KRW	0.433	0.640	0.499	1.087	0.548	0.048	−2.586	1.424	0.070
≥2 million KRW	−0.938	0.998	0.348	0.133	0.854	0.876	−1.409	2.220	0.526
Spouse (yes/no)	0.231	0.440	0.600	−0.073	0.376	0.846	−0.040	0.978	0.967
Duration	0.044	0.028	0.114	0.035	0.024	0.145	0.066	0.062	0.286
Drug count	0.149	0.105	0.159	0.076	0.090	0.399	0.105	0.234	0.655
Medication frequency (twice/once)	0.851	0.718	0.236	0.528	0.614	0.390	−1.502	1.596	0.347
Comorbidity (yes/no)	0.176	0.424	0.678	−0.304	0.363	0.402	0.542	0.944	0.566
Self-rated health (reference: good)
Moderate	0.298	0.618	0.630	−0.253	0.528	0.632	−1.091	1.374	0.428
Bad	0.641	0.639	0.317	−0.400	0.546	0.464	−0.934	1.421	0.511

Note: Regression coefficients are presented as n (%) unless otherwise indicated.

Abbreviations: BMQ, beliefs about medicines questionnaire; SE, standard error; KRW, Korean Won.

Figure 3 Standardized coefficients of structural equation model.

Notes: χ²=122.644, GFI =0.998, AGFI =0.997, TLI =0.972, CFI =0.903, WRMR =0.775 and RMSEA =0.045, *P<0.05, **P<0.01, ***P<0.001.
Abbreviations: AGFI, adjusted goodness of fit index; CFI, comparative fit index; GFI, goodness of fit index; RMSEA, root mean square error of approximation; TLI, Tucker-Lewis index; WRMR, weighted root mean square residual.

Table 6 Indirect effects of BMQ and self-efficacy on intentional nonadherence

Path	Indirect	Total
Necessity → Unintentional nonadherence → Intentional nonadherence	−0.113*	−0.388
Concern → Unintentional nonadherence → Intentional nonadherence	−0.006	0.126
Self-efficacy → Unintentional nonadherence → Intentional nonadherence	−0.286**	−0.341

Notes: χ²=122.644, GFI =0.998, AGFI =0.997, TLI =0.972, CFI =0.903, WRMR =0.775, and RMSEA =0.045. All regression coefficients are standardized,

* P<0.05,

** P<0.01.

Abbreviations: BMQ, beliefs about medicines questionnaire; AGFI, adjusted goodness of fit index; CFI, comparative fit index; GFI, goodness of fit index; RMSEA, root mean square error of approximation; TLI, Tucker-Lewis index; WRMR, weighted root mean square residual.