An evaluation of adherence in patients with multiple sclerosis newly initiating treatment with a self-injectable or an oral disease-modifying drug

Figures & data

Table 1 Self-injectable and oral DMDs

Type	Generic name	Brand namea
Self-injectable DMD	Interferon beta-1a	Avonex^®
	Interferon beta-1b	Betaseron^®
	Glatiramer acetate	Copaxone^®
	Interferon beta-1b	Extavia^®
	Interferon beta-1a	Rebif ^®
Oral DMD	Teriflunomide	Aubagio^®
	Fingolimod	Gilenya^®
	Dimethyl fumarate	Tecfidera^®

Notes:

a Aubagio^® (teriflunomide) is a registered trademark of Genzyme Corporation (Cambridge, MA, USA); Avonex^® (interferon beta-1a) is a registered trademark of Biogen (Cambridge, MA, USA); Betaseron^® (interferon beta-1b) is a registered trademark of Bayer (Whippany, NJ, USA); Copaxone^® (glatiramer acetate injection) is a registered trademark of Teva Pharmaceutical Industries Ltd. (Overland Park, KS, USA); Extavia^® (interferon beta-1b) is a registered trademark of Novartis AG (East Hanover, NJ, USA); Gilenya^® (fingolimod) is a registered trademark of Novartis AG (Stein, Switzerland); Rebif ^® (interferon beta-1a) is a registered trademark of EMD Serono, Inc. (Rockland, MA, USA; a business of Merck KGaA, Darmstadt, Germany); Tecfidera^® (dimethyl fumarate) is a registered trademark of Biogen.

Abbreviation: DMD, disease-modifying drug.

Figure 1 Patient selection flowchart.

Abbreviations: DMD, disease-modifying drug; ICD-9-CM, International Classification of Diseases, Ninth Revision, Clinical Modification; MS, multiple sclerosis.

Table 2 Baseline demographic and clinical characteristics of patients with MS newly initiating a DMD

Characteristics	Self-injectable DMD	Oral DMD	P-value
n	7,207	1,175	–
Age, years, mean	43.0	44.9	<0.0001
Age group, years, n (%)			<0.0001
18–34	1,654 (22.9)	187 (15.9)
35–44	2,217 (30.8)	352 (30.0)
45–54	2,201 (30.5)	428 (36.4)
55–64	1,135 (15.7)	208 (17.7)
Female, n (%)	5,531 (76.7)	895 (76.2)	0.6825
Region, n (%)			0.7851
Northeast	2,240 (31.1)	368 (31.3)
Midwest	2,409 (33.4)	376 (32.0)
South	2,151 (29.8)	362 (30.8)
West	407 (5.6)	69 (5.9)
CCI score, mean	0.55	0.48	0.0242
Select comorbidities, n (%)
Anxiety	940 (13.0)	149 (12.7)	0.7789
Arthritis (RA/OA)	556 (7.7)	87 (7.4)	0.7676
Depression	410 (5.7)	78 (6.6)	0.2017
Diabetes	568 (7.9)	80 (6.8)	0.2162
Gastrointestinal diseasea	1,227 (17.0)	234 (19.9)	0.0180
Hypertension	1,715 (23.8)	255 (21.7)	0.1193
Thyroid disease	1,117 (15.5)	180 (15.3)	0.8962

Notes: Due to rounding, percentages do not always equal 100%.

a Includes constipation, diarrhea, dysphagia, gastroesophageal reflux disease, and irritable bowel syndrome.

Abbreviations: CCI, Charlson Comorbidity Index; DMD, disease-modifying drug; MS, multiple sclerosis; OA, osteoarthritis; RA, rheumatoid arthritis.

Table 3 Adherence and discontinuation characteristics among patients with MS newly initiating a DMD: unadjusted bivariate analyses

Characteristics	Self-injectable DMD	Oral DMD	P-value
n	7,207	1,175	–
Adherence
Mean MPR (SD)	0.69 (0.30)	0.68 (0.30)	0.0002
Adherent to therapy,a n (%)	3,898 (54.1)	623 (53.0)	0.5075
Remained on index therapy, n (%)	4,574 (63.5)	766 (65.2)	0.2660
Discontinued index therapy,b n (%)	1,917 (26.6)	331 (28.2)	0.2710
Mean time to discontinuation, days (SD)	118.0 (79.3)	113.7 (86.2)	0.1341
Switched to other DMD,c n (%)	716 (9.9)	78 (6.6)	0.0003
Switched to self-injectable, n (%)	337 (47.1)	46 (59.0)
Switched to oral, n (%)	255 (35.6)	22 (28.2)
Switched to other, n (%)	124 (17.3)	10 (12.8)
Mean days to switch (SD)	163.1 (75.7)	153.1 (80.0)	0.2519

Notes:

a Defined as MPR ≥0.8;

b defined as absence of the index DMD for ≥90 days during the follow-up period without switching to another DMD during those 90 days;

c defined as switching from the index DMD to another DMD.

Abbreviations: DMD, disease-modifying drug; MPR, medication possession ratio; MS, multiple sclerosis; SD, standard deviation.

Table 4 Multivariable analysis of potential predictors of adherence

Covariate	OR estimate	Lower 95% CI	Upper 95% CI	P-value
Male (vs female)	1.203	1.085	1.335	0.0005
Age group, years (vs 18–34)
35–44	1.220	1.081	1.376	0.0013
45–54	1.331	1.178	1.505	<0.0001
55–64	1.321	1.138	1.533	0.0003
Select comorbidities (vs none)
Anxiety	1.047	0.917	1.195	0.4995
Arthritis (RA/OA)	0.909	0.770	1.073	0.2586
Depression	0.618	0.511	0.747	<0.0001
Diabetes	0.906	0.767	1.072	0.2505
Gastrointestinal disease	0.893	0.795	1.003	0.0572
Hypertension	0.939	0.841	1.049	0.2661
Thyroid disease	0.947	0.838	1.069	0.3781
Self-injectable DMD (vs oral DMD)	1.062	0.937	1.202	0.3473

Abbreviations: CI, confidence interval; DMD, disease-modifying drug; OA, osteoarthritis; OR, odds ratio; RA, rheumatoid arthritis.