Psychometric properties of the Polish version of the eight-item Morisky Medication Adherence Scale in hypertensive adults

Figures & data

Table 1 Characteristics of patients according to the groups of adherence

Characteristic	Total (n=110)	Low (n=27)	Medium (n=43)	High (n=40)	F/χ^2	P-value
Age (y), n (SD)	60.7 (12.6)	58.1 (13.0)	60.2 (13.6)	62.9 (11.0)	1.231	0.296
BMI (kg/m^2), n (SD)	27.8 (4.4)	28.9 (4.5)	27.6 (4.5)	27.3 (4.0)	1.081	0.343
Female	60 (54.6%)	14 (51.8%)	22 (51.2%)	24 (60.0%)	0.757	0.685
Education level					5.271	0.261
Primary and below	31 (28.2%)	5 (18.5%)	16 (37.2%)	10 (25.0%)
Secondary school	55 (50.0%)	17 (63.0%)	16 (37.2%)	22 (55.0%)
College and above	24 (21.8%)	5 (18.5%)	11 (25.6%)	8 (20.0%)
Marital status					3.115	0.374
Marriage and partnership	74 (67.3%)	17 (63.0%)	33 (76.7%)	24 (60.0%)
Divorcee/single	15 (13.7%)	5 (18.5%)	4 (9.3%)	6 (15.0%)
Widow/widower	21 (19.1%)	5 (18.5%)	6 (14.0%)	10 (25.0%)
Employment status					4.744	0.577
Working	48 (43.6%)	12 (44.4%)	20 (46.5%)	16 (40.0%)
Retired	51 (46.4%)	11 (40.8%)	18 (41.9%)	22 (55.0%)
Pensioned	8 (7.3%)	3 (11.1%)	3 (7.0%)	2 (5.0%)
Unemployed	3 (2.7%)	1 (3.7%)	2 (4.6%)	0 (0.0%)
Time from HBP diagnosis	9.5 (7.5)	9.3 (6.3)	10.9 (8.4)	8.2 (7.0)	1.343	0.265
Classification of hypertension					9.283	0.158
Normal	3 (2.7%)	0 (0.0%)	0 (0.0%)	3 (7.5%)
High-normal	18 (16.4%)	4 (14.8%)	10 (23.3%)	4 (10.0%)
Grade 1 (mild)	59 (53.6%)	16 (59.3%)	20 (46.5%)	23 (57.5%)
Grade 2 (moderate)	30 (27.3%)	7 (25.9%)	13 (30.2%)	10 (25.0%)
Nicotine addiction					7.183	0.127
Never smoked	60 (55.0%)	12 (44.4%)	23 (53.5%)	25 (64.1%)
No longer smoker	20 (18.4%)	3 (11.2%)	9 (20.9%)	8 (20.5%)
Current smoker	29 (26.6%)	12 (44.4%)	11 (25.6%)	6 (15.4%)
Alcohol					6.636	0.465
At all	37 (33.6%)	7 (25.9%)	13 (30.2%)	17 (42.5%)
Sometimes	65 (59.1%)	17 (63.0%)	26 (60.5%)	22 (55.0%)
Often	7 (6.4%)	3 (11.1%)	3 (7.0%)	1 (2.5%)
Daily	1 (0.9%)	0 (0.0%)	1 (2.3%)	0 (0.0%)
Frequency of BP control					33.46	0.001
Three times a day	9 (8.2%)	2 (7.4%)	3 (7.0%)	4 (10.0%)
Twice a day	32 (29.1%)	7 (25.9%)	10 (23.3%)	15 (37.5%)
Once a day	34 (30.9%)	5 (18.5%)	13 (30.2%)	16 (40.0%)
Once a week	14 (12.7%)	1 (3.7%)	10 (23.3%)	3 (7.5%)
Only a doctor	8 (7.3%)	3 (11.1%)	5 (11.6%)	0 (0.0%)
When ill feeling	13 (11.8%)	9 (33.3%)	2 (4.6%)	2 (5.0%)
Frequency of medication					5.664	0.226
More often than once a day	36 (32.7%)	10 (37.0%)	17 (39.5%)	9 (22.5%)
Once a day	66 (60.0%)	14 (51.9%)	25 (58.1%)	27 (67.5%)
Number of medications daily	3.61 (4.31)	5.42 (3.64)	4.75 (3.18)	2.64 (3.18)	7.862	0.062

Note: Statistical significance marked in bold.

Abbreviations: BP, blood pressure; HBP, high blood pressure; BMI, body mass index.

Table 2 Analysis of adherence levels of MMAS depending on the degree of illness acceptance

Morisky Medication Adherence Scale	Moderate illness acceptance (19–29 points)
Do you sometimes forget to take your pills?	0.66±0.47
People sometimes miss taking their medications for reasons other than forgetting. Thinking back over the past 2 weeks, were there any days when you did not take your medicine?	0.81±0.39
Have you every cut back on or stopped taking your medication without telling your doctor, because you felt worse when you took it?	0.83±0.38
When you travel or leave home, do you sometimes forget to take your medication with you?	0.74±0.44
Did you take your medicine yesterday?	0.87±0.33
When you feel like your illness is under control, do you sometimes stop taking your medicine?	0.84±0.37
Taking medication every day is a real inconvenience for some people. Do you ever feel hassled about sticking to your treatment plan?	0.80±0.40
How often do you have difficulty remembering to take all your medications?	0.88±0.21
Never/Rarely (4)
Once in a while (3)
Sometime (2)
Usually (1)
All the time (0)
MMAS-8-Total	6.42±2.00
Adherence level, n (%)
Low adherence (<6)	27 (24.5)
Medium adherence (6–8)	43 (39.1)
High adherence (=8)	40 (36.4)

Notes: Use of the ©MMAS-8 is protected by the US copyright laws. Permission for use is required. A licensure agreement is available from Donald E Morisky, ScD, ScM, MSPH, Professor, Department of Community Health Sciences, UCLA School of Public Health, 650 Charles E Young Drive South, Los Angeles, CA 90095-1772; [e-mail]. Data shown as mean ± SD unless stated otherwise.

Abbreviation: MMAS-8, eight-item Morisky Medication Adherence Scale.

Table 3 Corrected item-to-total correlation and factors loading of the Polish MMAS-8

Items	Patients’ responses	Entry (n=110), number (%)	Corrected item-to-total correlation	α if deleted	Factor
					Factor 1	Factor 2
Q1	No	73 (66.4)	0.589	0.777	0.719	0.032
Q2	No	89 (80.9)	0.565	0.780	0.700	−0.218
Q3	No	91 (82.7)	0.524	0.786	0.670	−0.198
Q4	No	81 (73.6)	0.661	0.763	0.784	0.010
Q5	Yes	96 (87.3)	0.031	0.849	0.055	0.955
Q6	No	92 (83.6)	0.686	0.762	0.800	−0.003
Q7	No	88 (80.0)	0.635	0.769	0.741	0.090
Q8	Never/rarely	3 (2.7)	0.580	0.791	0.692	0.199
	Once in a while	10 (9.1)
	Sometimes	20 (18.2)
	Usually	76 (69.1)
	All the time	1 (0.9)

Note: Statistically significant values are shown in bold.

Abbreviations: n, sample size; MMAS-8, eight-item Morisky Medication Adherence Scale; α, Cronbach’s alpha coefficient.

Table 4 Relations between level of adherence and blood pressure control groups

Adherence level (MMAS-8)	Blood pressure		Mean (SD)
	Control		Blood pressure values
	Yes, n (%)	No, n (%)	SBP, mmHg	DBP, mmHg
Low adherence (<6)	4 (19.1)	23 (25.8)	145 (17)	90 (8)
Medium adherence (6 to <8)	10 (47.6)	33 (37.1)	147 (14)	91 (12)
High adherence (8)	7 (33.3)	33 (37.1)	141 (11)	84 (12)

Abbreviations: SBP, systolic blood pressure; DBP, diastolic blood pressure; SD, standard deviation; MMAS-8, eight-item Morisky Medication Adherence Scale.

Table 5 Test–retest result

Questions (items)	Test 1	Test 2					κ	ρ
		No				Yes		C (%)
Q1 Do you sometimes forget to take your antihypertensive pills?	No	72				5	0.874	0.878
	Yes	1				32		94.5%
Q2 People sometimes miss taking their medications for reasons other than forgetting. Thinking over the past 2 weeks, were there any days when you did not take your antihypertensive medicine?	No	88				7	0.751	0.751
	Yes	1				14		92.7%
Q3 Have you ever cut back or stopped taking your medication without telling your doctor, because you felt worse when you took it?	No	87				1	0.850	0.854
	Yes	4				18		95.5%
Q4 When you travel or leave home, do you sometimes forget to bring along your antihypertensive medicine?	No	80				3	0.904	0.905
	Yes	1				26		95.5%
Q5 Did you take your antihypertensive medicine yesterday?	No	8				8	0.460	0.461
	Yes	6				88		12.7%
Q6 When you feel like your hypertension is under control, do you sometimes stop taking your medicine?	No	90				2	0.867	0.867
	Yes	2				16		96.4%
Q7 Taking medication every day is a real inconvenience for some people. Do you ever feel hassled about sticking to your antihypertensive treatment plan?	No	86				5	0.790	0.794
	Yes	2				17		93.6%
	Test 1	Test 2
		a)	b)	c)	d)	e)
Q8 How often do you have difficulty remembering to take all your medications?
Never/rarely	a)	75	1	1	1	1	0.727	0.854
Once in a while	b)	0	15	1	0	0
Sometimes	c)	1	4	8	0	0		90.1%
Usually	d)	0	0	0	2	0
All the time	e)	0	0	0	0	0

Abbreviations: κ, Cohen’s kappa coefficient; ρ, Spearman’s rank correlation coefficient; C, consistency.

Table 6 Frequency table and χ² test

Test 2 Adherence level	Test 1 Adherence level			Percentage (%)
	Low	Medium	High
Low	26	2	1	26.4
Medium	1	29	4	30.9
High	0	12	35	42.7
	24.5%	39.1%	36.4%

Notes: χ²=129.6, df =4, P<0.0001, κ=0.606.

Abbreviations: df, degrees of freedom; κ, Cohen’s kappa coefficient.