Health-Related Quality of Life and the Relationship to Treatment Satisfaction in Patients with Multiple Sclerosis: Insights from a Large Observational Study

Figures & data

Table 1 Patient Characteristics (N=2990)

		Percent	(95% CI)
Gender	Female	73.3%	(71.72–74.92)
Employment	Not Working	32.5%	(30.79–34.22)
Living with a partner	No	23.3%	(21.78–24.96)
Disease course	CIS	5.3%	(4.54–6.18)
	RRMS	94.7%	(93.82–95.46)
Fatigue	Yes	45.5%	(43.74–47.37)
Depression	Yes	16.9%	(15.55–18.30)
Relapses	One or more	37.5%	(35.74–39.25)
Current disease-modifying therapy	Yes (IFN/GA)	91.6%	(73.93–94.11)
	No DMT	8.4%	(05.89–26.07)
Duration of medication intake	<2 years	29.1%	(27.48–30.80)
	2–8 years	44.8%	(42.94–46.57)
	>8 years	26.1%	(24.55–27.76)
Number of medication changes	No changes	71.8%	(70.15–73.43)
	1 change	20.2%	(18.78–21.71)
	≥2 changes	8.0%	(7.02–9.01)
Age (years)	Mean (95%-CI)	43.36	(42.96–43.76)
	Median (IQR)	44.00	(35.00–51.00)
EDSS	Mean (95%-CI)	2.26	(2.21–2.32)
	Median (IQR)	2.00	(1.00–3.00)
Disease duration	Mean (95%-CI)	8.78	(8.54–9.02)
	Median (IQR)	7.00	(3.00–12.00)
TSQM effectiveness	Mean (95%-CI)	66.78	(65.92–67.65)
	Median (IQR)	66.67	(50.00–83.33)
TSQM side effects	Mean (95%-CI)	74.57	(73.55–75.58)
	Median (IQR)	81.25	(56.25–100)
TSQM convenience	Mean (95%-CI)	70.24	(69.47–71.01)
	Median (IQR)	66.67	(55.56–88.89)

Notes: Disease-related and sociodemographic variables describing the patient population.

Abbreviations: CI, confidence interval; IQR, interquartile range (25th to 75th percentile); RRMS, relapsing-remitting multiple sclerosis; CIS, clinically isolated syndrome; DMT, disease-modifying treatment; IFN, interferon; GA, glatiramer acetate; EDSS, Expanded Disability Status Scale; TSQM, Treatment Satisfaction Questionnaire for Medication.

Table 2 Health-Related Quality of Life (SF-36) Score Distributions in Patients on First-Line Treatment (N=2990)

		Current Medication
		IFN beta-1a i.m. (N=704)	IFN beta-1a s.c. (N=687)	IFN beta-1b s.c. (N=564)	GA (N=785)	No DMT (N=250)
PCS*	Mean (CI)	47.20 (46.35–48.06)	45.88 (44.97–46.78)	45.32 (44.27–46.37)	44.99 (44.12–45.87)	41.40 (39.76–43.04)
	Median (IQR)	48.54 (39.66–56.61)	47.85 (37.54–56.07)	46.92 (36.14–55.95)	45.88 (36.05–55.40)	41.78 (30.96–51.24)
MCS*	Mean (CI)	44.35 (43.49–45.22)	42.99 (42.08–43.90)	43.77 (42.74–44.80)	41.67 (40.77–42.58)	39.98 (38.28–41.68)
	Median (IQR)	46.63 (35.02–53.77)	44.73 (34.86–53.02)	44.69 (35.48–54.35)	42.90 (32.76–52.20)	40.48 (29.17–51.65)
PF**	Mean (CI)	75.81 (73.90–77.72)	73.02 (70.99–75.05)	70.35 (67.95–72.75)	71.46 (69.54–73.39)	62.35 (58.59–66.11)
	Median (IQR)	85.00 (60.00–95.00)	80.00 (55.00–95.00)	80.00 (45.00–95.00)	80.00 (50.00–95.00)	65.00 (37.50–90.00)
RF**	Mean (CI)	66.87 (64.81–68.92)	64.69 (62.58–66.81)	62.98 (60.58–65.37)	60.06 (58.04–62.08)	50.91 (47.38–54.43)
	Median (IQR)	68.75 (43.75–93.75)	68.75 (43.75–87.50)	62.50 (43.75–87.50)	62.50 (37.50–87.50)	50.00 (31.25–75.00)
BP**	Mean (CI)	72.19 (70.22–74.15)	71.07 (68.97–73.16)	72.21 (69.91–74.51)	69.28 (67.26–71.30)	63.82 (59.78–67.68)
	Median (IQR)	74.00 (51.00–100.0)	74.00 (51.00–100.0)	74.00 (51.00–100.0)	72.00 (41.00–100.0)	62.00 (41.00–100.0)
GH**	Mean (CI)	57.95 (56.39–59.50)	54.17 (52.53–55.81)	55.79 (53.98–57.59)	54.23 (52.73–55.73)	50.20 (47.45–52.95)
	Median (IQR)	57.00 (42.00–72.00)	52.00 (37.00–72.00)	57.00 (40.00–72.00)	52.00 (37.00–72.00)	47.00 (35.00–67.00)
VT**	Mean (CI)	49.76 (48.30–51.23)	47.00 (45.49–48.51)	48.37 (46.72–50.03)	45.40 (43.93–46.87)	41.18 (38.63–43.72)
	Median (IQR)	50.00 (37.50–62.50)	50.00 (31.25–62.50)	50.00 (31.25–62.50)	43.75 (31.25–62.50)	43.75 (25.00–56.25)
SF**	Mean (CI)	75.94 (74.16–77.73)	74.73 (72.79–76.76)	74.62 (72.45–76.79)	71.14 (69.23–73.05)	65.12 (61.63–68.61)
	Median (IQR)	75.00 (62.50–100.0)	75.00 (62.50–100.0)	75.00 (62.50–100.0)	75.00 (50.00–100.0)	62.50 (50.00–87.50)
RE**	Mean (CI)	72.36 (70.27–74.46)	68.74 (66.61–70.87)	69.34 (66.98–71.71)	66.17 (64.08–68.25)	59.64 (55.75–63.52)
	Median (IQR)	75.00 (50.00–100.0)	75.00 (50.0–100.0)	75.00 (50.00–100.0)	66.67(50.00–100.0)	58.33 (33.33–91.67)
MH**	Mean (CI)	67.33 (65.90–68.76)	65.50 (64.07–66.93)	67.16 (65.56–68.77)	64.47 (63.05–65.88)	61.80 (59.20–64.40)
	Median (IQR)	70.00 (55.00–83.33)	70.00 (50.00–80.00)	70.00 (55.00–85.00)	65.00 (50.00–80.00)	65.00 (45.00–80.00)
TSQM global*	Mean (CI)	72.35 (70.82–73.87)	72.31 (70.81–73.82)	72.63 (70.87–74.39)	71.45 (69.99–72.91)	45.75 (41.25–50.25)
	Median (IQR)	78.57 (57.14–85.71)	78.57 (57.14–85.71)	78.57 (57.14–92.86)	71.43 (57.14–85.71)	42.86 (21.43–71.43)

Notes: *ANOVA result: p <0.01 (IFN beta-1a i.m. vs IFN beta-1a s.c. vs IFN beta-1b s.c. vs GA vs No DMT), two sample t-test result: p <0.01 (No DMT vs IFN/GA). **Kruskal–Wallis result: p <0.01 (IFN beta-1a i.m. vs IFN beta-1a s.c. vs IFN beta-1b s.c. vs GA vs No DMT), Mann–Whitney U-test result: p <0.01 (No DMT vs IFN/GA).

Abbreviations: CI, (95%) confidence interval; IQR, interquartile range (25th to 75th percentile); DMT, disease-modifying treatment; IFN, interferon; GA, glatiramer acetate; i.m., intramuscular; s.c., subcutaneous; PCS, Physical Component Summary Score; MCS, Mental Component Summary Score; PF, physical functioning; RF, role-physical; BP, bodily pain; GH, general health; VT, vitality; SF, social functioning; RE, role-emotional; MH, mental health; TSQM, Treatment Satisfaction Questionnaire for Medication.

Table 3 Rank Correlation Results for Treatment Satisfaction and Health-Related Quality of Life (N=2990)

	PCS	MCS	PF	RF	BP	GH	VT	SF	RE	MH
TSQM effectiveness	0.352	0.310	0.283	0.338	0.272	0.373	0.326	0.321	0.274	0.286
TSQM side effects	0.199	0.247	0.121	0.181	0.259	0.208	0.255	0.231	0.193	0.219
TSQM convenience	0.102	0.227	0.052	0.103	0.121	0.189	0.189	0.181	0.162	0.215
TSQM global satisfaction	0.270	0.314	0.199	0.251	0.232	0.334	0.295	0.294	0.250	0.300

Abbreviations: TSQM, Treatment Satisfaction Questionnaire for Medication; PCS, Physical Component Summary Score; MCS, Mental Component Summary Score; PF, physical functioning; RF, role-physical; BP, bodily pain; GH, general health; VT, vitality; SF, social functioning; RE, role-emotional; MH, mental health.

Table 4 Cross-Sectional Predictors of Physical Health and Mental Health Domains: Multivariate Regression Analyses (N=2990)

	PCS Model (N=2439)		MCS Model (N=2439)
	b	P-value	b	P-value
TSQM effectiveness	+0.137	<0.001	+0.131	<0.001
TSQM side effects	+0.146	<0.001	+0.152	<0.001
TSQM convenience			+0.116	<0.001
Age	−0.159	<0.001
Employment status^a)	+0.163	<0.001	+0.075	<0.001
Fatigue^b)	−0.117	<0.001	−0.130	<0.001
Depression^b)	−0.059	<0.001	−0.234	<0.001
Disability	−0.408	<0.001	−0.052	0.012
Relapses ^c)	−0.077	<0.001	−0.085	<0.001
Current DMT ^d)			+0.030	0.103
R/R^2 adjusted	0.726/0.526 <1.5		0.502/0.249 <1.4
Maximum VIF

Notes: Standardized beta coefficients (b) and p-values of LASSO-selected cross-sectional predictors in linear regression models with PCS and MCS as dependent variables. For a one standard deviation increase in a given variable, holding the other explanatory variables constant, the outcome variable (PCS, MCS) changes by the standardized coefficient number of standard deviations. a) Working vs not working, b) Yes vs no, c) More than one relapse vs no relapse in the past 12 months, d) IFN/GA vs No DMT.

Abbreviations: b, standardized beta coefficients; TSQM, Treatment Satisfaction Questionnaire for Medication; DMT, disease-modifying treatment; IFN, interferon; GA, glatiramer acetate; PCS, Physical Component Summary Score; MCS, Mental Component Summary Score; VIF, variance inflation factor; R, coefficient of determination; LASSO, least absolute shrinkage and selection operator.

Figure 1 Regression tree for the Physical Component Summary (PCS).

Notes: The tree was recursively grown based on the restriction of a minimum node size of 50 and a maximum number of 5 tree layers. Variables included: TSQM effectiveness, TSQM side effects, TSQM convenience, type of medication (DMT), number of medication changes, duration of medication intake, disease duration, disease course (CIS, RRMS), EDSS, relapses in the last 12 months, fatigue, depression, gender, age, currently living with a partner, employment status.

Figure 2 Regression tree for the Mental Component Summary (MCS).

Notes: The tree was recursively grown based on the restriction of a minimum node size of 50 and a maximum number of 5 tree layers. Variables included: TSQM effectiveness, TSQM side effects, TSQM convenience, type of medication (DMT), number of medication changes, duration of medication intake, disease duration, disease course (CIS, RRMS), EDSS, relapses in the last 12 months, fatigue, depression, gender, age, currently living with a partner, employment status.