Development and validation of a revised instrument to measure burden of long-term medicines use: the Living with Medicines Questionnaire version 3

Figures & data

Figure 1 Flow diagrams illustrating respondent numbers in each stage of the study.

Abbreviations: LMQ, Living with Medicines Questionnaire; EFA, exploratory factor analyses; CFA, confirmatory factor analyses; KARU; Kent Adult Research Unit.

Table 1 Characteristics of study participants

		Stage 1		Stage 2	Stage 3
		Construct validation study		Criterion validation study	Test–retest
Characteristics		EFA subset n (%)	CFA subset n (%)	n (%)	n (%)
Gender	Female	312 (86.7)	300 (85.0)	208 (52.8)	20 (67)
	Male	48 (13.3) (n=360)	53 (15.0) (n=353)	186 (47.2) (n=394)	10 (33) (n=30)
Age group (years)	18–29	25 (7.0)	26 (7.3)	51 (12.1)	1 (3)
	30–49	155 (43.2)	159 (45.0)	81 (19.3)	1 (3)
	50–64	153 (42.6)	137 (38.7)	118 (28.1)	5 (17)
	≥65	26 (7.2) (n=359)	32 (9.0) (n=354)	170 (40.5) (n=420)	23 (77) (n=30)
Education level	School	73 (20.5)	66 (18.7)	158 (40.3)	5 (17)
	Technical college	86 (24.2)	93 (26.3)	117 (29.9)	5 (17)
	University	161 (45.2)	168 (47.6)	89 (22.7)	17 (57)
	Other	36 (10.1) (n=356)	26 (7.4) (n=353)	28 (7.1) (n=392)	3 (10) (n=30)
Employment status	Employed	163 (45.8)	168 (47.5)	159 (38.8)	5 (17)
	Unemployed	36 (10.1)	48 (13.5)	44 (10.7)	0 (0)
	Retired	67 (18.8)	59 (16.7)	187 (45.6)	23 (77)
	Full-time student	10 (2.8)	10 (2.8)	20 (4.9)	0 (0)
	Other	80 (22.5) (n=356)	69 (19.5) (n=354)	0 (n=410)	2 (7) (n=30)
Ethnicity	White	345 (96.1)	339 (95.8)	353 (86.5)	29 (97)
	Asian/Asian British	3 (0.8)	3 (0.8)	15 (3.7)	0 (0)
	Mixed	1 (0.3)	6 (1.7)	10 (2.4	1 (3)
	Black/African/Caribbean	2 (0.6)	2 (0.6)	26 (2.4)	0 (0)
	Other	8 (2.2) (n=359)	4 (1.1) (n=354)	4 (1.0) (n=408)	0 (0) (n=30)
Number of medicines	1–4	220 (61.1)	212 (59.9)	236 (56.7)	16 (53)
	5–9	107 (29.7)	112 (31.6)	126 (30.3)	14 (47)
	≥10	33 (9.2) (n=360)	30 (8.5) (n=354)	54 (13.0) (n=416)	0 (0) (n=30)
Formulation usedc	Tablets/capsules	349 (95.3)	343 (94.5)	374 (92.6)	28 (93)
	Any other formulation	151 (41.2) (n=366)	166 (45.7) (n=363)	120 (29.7 (n=404)	16 (53)
Frequency of medicine usec	Once daily	160 (43.7)	169 (46.5)	146 (35.9)	18 (60)
	Twice daily	151 (41.2)	134 (36.9)	136 (33.5)	10 (33)
	Three times daily	76 (20.8)	73 (20.1)	49 (12.1)	6 (20)
	≥4 times daily	55 (15.0)	65 (17.9)	47 (11.6)	1 (3)
	Other timesa	50 (13.7) (n=366)	54 (14.9) (n=363)	28 (6.9) (n=406)	2 (7)
Assisted in using medicines	No - independent	306 (85.2)	309 (87.3)	349 (85.7)	29 (97)
	Yes - has a caretaker	53 (14.8) (n=359)	45 (12.7) (n=354)	58 (14.3) (n=407)	1 (3) (n=30)
	Spouse/partner	34 (64.2)	33 (73.3)	33 (58.9)	1 (3)
	Relative	9 (17.0)	1 (2.2)	10 (17.9)	0 (0)
	Support worker	4 (7.5)	3 (6..7)	7 (12.5)	0 (0)
	Friend	1 (1.9)	1 (2.2)	4 (7.1)	0 (0)
	Otherb	5 (9.4) (n=53)	7 (15.6) (n=45)	2 (3.6) (n=56)	0 (0)
Pays for prescriptions	No	245 (68.1)	248 (70.1)	267 (66.6)	27 (90)
	Yes	115 (31.9) (n=360)	106 (29.9) (n=354)	141 (33.4)	3 (10) (n=30)

Notes:

a Includes medicines PRN, different times of the week, fortnightly, monthly, every 3 months;

b includes nurse or multiple support from relatives, friends, and caretakers.

c participants could choose more than one response option, thus proportions are estimated for each category.

Abbreviations: EFA, exploratory factor analyses; CFA, confirmatory factor analyses; PRN, taken as needed.

Table 2 EFA-derived factor structure of the LMQ-3 (N=366)

Items	Derived factors
	Int	Relat	Effec	Conc	SideE	Prac	Cost	Auto
Interferences with day-to-day life (a=0.865)
My medicines interfere with my social relationships.	0.892	0.060	0.009	–0.121	–0.002	–0.001	0.062	0.018
My medicines interfere with my social or leisure activities.	0.779	0.078	–0.022	0.139	–0.015	–0.052	–0.079	0.000
Taking medicines affects my driving.	0.690	–0.045	–0.064	0.030	–0.034	–0.039	–0.002	–0.023
Taking medicines causes me problems with daily tasks (such as work, housework, hobbies).	0.644	0.025	0.052	–0.112	0.319	–0.105	0.066	0.014
My medicines interfere with my sexual life.	0.643	0.036	0.006	–0.036	0.056	0.011	0.088	–0.023
My life revolves around using my medicines.	0.480	0.034	–0.078	0.089	0.102	0.066	0.052	0.023
Patient–doctor relationships and communication about medicines (a=0.870)
My doctor(s) listen to my opinions about my medicines.	0.032	0.810	–0.051	–0.018	–0.028	0.048	–0.042	0.047
My doctor(s) take my concerns about side effects seriously.	0.059	0.794	0.015	–0.061	–0.009	–0.066	0.042	–0.002
I get enough information about my medicines from my doctor(s).	0.049	0.761	0.000	0.094	–0.033	0.025	–0.014	0.043
The health professionals providing my care know enough about me and my medicines.	–0.001	0.612	0.133	0.044	–0.051	0.085	–0.048	–0.033
I trust the judgment of my doctor(s) in choosing medicines for me.	0.001	0.556	0.152	0.027	0.007	0.137	–0.031	–0.085
Lack of effectiveness (a=0.851)
My medicines are working.	–0.142	–0.026	0.882	–0.004	0.072	–0.007	0.067	0.083
My medicines live up to my expectations.	–0.043	0.062	0.711	0.084	0.066	0.057	0.040	0.064
I am satisfied with the effectiveness of my medicines.	–0.026	0.061	0.719	0.054	0.078	0.032	–0.071	–0.018
The side effects are worth it for the benefits I get from my medicines.	–0.151	0.173	0.601	0.046	–0.077	–0.225	0.062	0.040
My medicines prevent my condition getting worse.	0.247	–0.044	0.523	–0.144	–0.142	0.160	–0.046	–0.134
My medicines allow me to live my life as I want to.	0.345	0.106	0.525	0.017	–0.084	0.023	–0.087	–0.007
General concerns about medicines (a=0.796)
I am concerned about possible damaging long-term effects of taking medicines.	–0.086	0.008	0.020	0.648	0.270	–0.035	–0.067	–0.076
I worry that my medicines may interact with each other.	–0.004	–0.073	0.128	0.639	0.165	–0.061	–0.018	0.003
I am concerned that I am too reliant on my medicines.	0.167	0.043	–0.028	0.635	–0.173	–0.099	0.037	–0.096
I worry that I have to take several medicines at the same time.	–0.056	–0.091	0.061	0.550	–0.003	0.135	0.126	–0.091
I am concerned that my medicines interact with alcohol.	0.339	–0.069	–0.015	0.505	–0.171	–0.169	0.060	0.158
I feel I need more information about my medicines.	–0.014	0.252	0.036	0.544	0.058	–0.010	0.022	0.016
I would like more say in the brands of medicines I use.	–0.196	0.200	–0.081	0.447	0.134	0.005	0.076	–0.009
Side effects (a=0.901)
The side effects I get from my medicines are bothersome.	0.131	–0.099	–0.072	0.054	0.812	0.063	–0.027	0.024
The side effects I get from my medicines interfere with my day-to-day life (e.g., work, housework, sleep).	0.355	–0.023	–0.014	–0.026	0.687	–0.072	0.031	0.009
The side effects I get are sometimes worse than the problem for which I take medicines.	0.051	0.029	0.078	0.030	0.647	0.016	–0.042	0.007
The side effects I get from my medicines adversely affect my well-being.	0.346	0.019	0.020	0.016	0.612	–0.040	–0.028	0.013
Practical difficulties (a=0.738)
I find getting my prescriptions from the doctor difficult.	–0.093	0.225	–0.110	–0.148	0.089	0.734	0.060	0.061
It is easy to keep to my medicines routine.	0.044	–0.079	0.174	–0.065	–0.024	0.631	–0.009	–0.018
I find getting my medicines from the pharmacist difficult.	–0.017	0.090	–0.111	0.033	–0.041	0.616	0.090	0.023
I am comfortable with the times I should take my medicines.	–0.048	–0.093	0.323	0.024	–0.024	0.398	0.031	0.010
I have to put a lot of planning and thought into taking my medicines.	0.295	–0.092	–0.116	0.169	0.145	0.464	–0.036	0.000
I am concerned that I may forget to take my medicines.	0.170	–0.139	–0.056	0.343	–0.162	0.421	–0.139	0.172
I find using my medicines difficult.	0.311	–0.020	0.028	0.102	0.086	0.410	–0.021	–0.102
Cost-related burden (a=0.801)
I have to pay more than I can afford for my medicines.	0.081	–0.039	0.029	0.028	–0.062	0.004	0.838	0.032
I sometimes have to choose between buying basic essentials or medicines.	0.130	0.002	0.109	–0.057	0.016	0.013	0.704	–0.050
I worry about paying for my medicines.	–0.071	–0.021	–0.102	0.165	–0.026	0.132	0.679	0.004
Lack of autonomy/control of medicine use (a=0.692)
I can choose whether or not to take my medicines.	0.051	–0.036	0.005	0.000	–0.012	–0.029	–0.020	0.732
I can vary the dose of the medicines I take.	–0.102	0.008	0.086	–0.179	0.089	0.035	0.033	0.668
I can vary the times I take my medicines.	0.050	0.058	0.000	0.051	–0.021	0.085	–0.018	0.628

Notes: All items are scored so that higher scores reflect worse experiences (higher burden) with medicine use. Statistically significant values are shown in bold.

Abbreviations: LMQ-3, Living with Medicines Questionnaire version 3; EFA, exploratory factor analyses; Int, interferences with day-to-day life; Relat, patient–doctor relationships and communication about medicines; Effec, lack of effectiveness; Conc, general concerns about medicines; Prac, practical difficulties; SideE, side effects; Cost, cost-related burden; Auto, lack of autonomy/control over medicine use.

Figure 2 Hierarchical CFA model for the 41-item Living with Medicines Questionnaire version 3.

Notes: Standardized path estimates are shown.
Abbreviations: CFA, confirmatory factor analyses; Int, interferences with day-to-day life; SideE, side effects; Conc, general concerns about medicines; Effec, lack of effectiveness; Prac, practical difficulties; Relat, patient–doctor relationships and communication about medicines; Cost, cost-related burden; Auto, lack of autonomy/control over medicine use; e1–e41 = variance associated each item; eI–eA represent variance associated with each of the eight factors or domains (interferences to autonomy respectively); Q, question.

Table 3 Correlations between domains of the LMQ-3 and TSQM-II subscales

LMQ-3	TSQM-II Satisfaction with effectiveness	TSQM-II Satisfaction with side effects	TSQM-II Satisfaction with convenience	TSQM-II Global satisfaction
Lack of effectiveness	–0.628	–0.376	–0.424	–0.571
Side-effect burden	–0.414	–0.597	–0.449	–0.516
Practical difficulties	–0.367	–0.405	–0.529	–0.426
Patient–doctor communication problems	–0.476	–0.278	–0.360	–0.394
Cost-burden	–0.141	–0.193	–0.157	–0.232
General concerns	–0.406	–0.469	–0.401	–0.410
Interferences with life	–0.360	–0.560	–0.451	–0.430
Lack of autonomy	0.139	0.010*	0.057*	0.121
LMQ-3 total score	–0.554	–0.623	–0.564	–0.616

Notes:

* Correlations not statistically significant at p<0.05 (Spearman’s correlation coefficient); correlations in bold indicate strongest associations.

Abbreviations: LMQ-3, Living with Medicines Questionnaire version 3; TSQM-II, Treatment Satisfaction Questionnaire with Medication.

Table 4 Known-groups validity of the LMQ-3

Characteristics		Mean LMQ-3 total score (SD)
		(N=336)	p-value
Age (years)	18–29	104.6 (18.4)
	30–49	108.4 (22.4)
	50–64	102.8 (20.5)
	≥65	98.4 (17.5)	0.007
Employment	Employed	103.2 (20.1)
	Unemployed	118.0 (21.5)
	Retired	98.3 (17.3)	<0.001
No of medicines	1–4	100.3 (17.7)
	5–9	107.8 (23.8)
	≥10	104.4 (20.3)	0.010
Frequency of use	Once daily	97.8 (16.0)
	Twice daily	101.7 (20.0)
	Three times daily	111.4 (23.8)
	≥4 times daily	112.7 (22.1)	<0.001
Managing medicines	Independent	100. 8 (19.5)
	Requires help	116.4 (17.8)	<0.001
Paying for prescriptions	No	100.6 (19.5)
	Yes	106.2 (20.3)	0.014

Abbreviation: LMQ-3, Living with Medicines Questionnaire version 3.

Figure 3 Number of missing responses to LMQ questions.

Abbreviations: LMQ, Living with Medicines Questionnaire; Q, question.

Table 5 Items with more than 2% missing data in Stage 2

Item number	Statement	Number missing	Percentage missing
Q5	I worry about paying for my medicines.	34	8.1
Q33	I have to pay more than I can afford for my medicines.	23	5.5
Q31	I sometimes have to choose between buying basic essentials or medicines.	16	3.9
Q37	My medicines interfere with my sexual life.	15	3.6
Q39	My medicines are working.	15	3.6
Q28	Taking medicines affects my driving.	14	3.3
Q30	The side effects I get from my medicines are bothersome.	11	2.6
Q38	The side effects I get from my medicines adversely affect my well-being.	11	2.6
Q29	I find using my medicines difficult.	10	2.4
Q34	The health professionals providing my care know enough about me and my medicines.	10	2.4
Q40	The side effects are worth it for the benefits I get from my medicines.	10	2.4

Table 6 Differences between full and partial respondents of LMQ-3 in Stage 2

Characteristics		Fully completed (N=336)	Partially completed (n=86)	p-value
Gender	Female	148 (47)	38 (49)
	Male	186 (51) (n=316)	168 (53) (n=78)	0.801
Age group (years)	18–29	45 (13)	6 (7)
	30–49	77 (23)	4 (5)
	50–64	99 (36)	19 (22)
	≥65	114 (34) (n=335)	56 (66) (n=85)	<0.001
Education level	School	115 (36)	43 (57)
	Technical college	98 (31)	19 (25)
	University	81 (26)	8 (11)
	Other	22 (7) (n=316)	17 (8) (n=76)	0.004
Employment status	Employed	142 (43)	17 (21)
	Unemployed	39 (12)	5 (6)
	Retired	129 (39)	58 (72)
	Full-time student	19 (6)	1 (1)
	Other	0 (n=329)	0 (n=81)	<0.001
Ethnicity	White	276 (84)	77 (95)
	Asian/Asian British	14 (4)	1 (1)
	Mixed	9 (3)	1 (1)
	Black/African/Caribbean	25 (8)	1 (1)
	Other	3 (1) (n=327)	1 (1) (n=81)	0.118
Number of medicines	1–4	201 (61)	35 (41)
	5–9	93 (28)	33 (39)
	≥10	37 (11) (n=331)	17 (20) (n=85)	0.004
Formulation used	Tablets/capsules	299 (92)	75 (95)
	Any other formulation	26 (8) (n=325)	4 (5) (n=79)	0.683
Frequency of medicine use	Once daily	121 (37)	25 (31)
	Twice daily	101 (31)	35 (43)
	Three times daily	39 (12)	10 (12)
	≥4 times daily	41 (13)	6 (7)
	Other times	23 (7) (n=325)	5 (6) (n=81)	0.269
Assisted in using medicines	No - independent	286 (87)	63 (79)
	Yes - has a caretaker	41 (13) (n=327)	17 (21) (n=80)	0.051
Pays for prescriptions	No	203 (62)	64 (80)
	Yes	125 (38) (n=328)	16 (20) (n=80)	0.002

Abbreviation: LMQ-3, Living with Medicines Questionnaire version 3.