Assessment of adherence to, and persistence with, an electromechanical autoinjector for subcutaneous interferon beta-1a injections for multiple sclerosis treatment over 3 years

Figures & data

Table 1. Baseline characteristics and first intake characteristics at index for all patients providing RebiSmart® usage data.

Baseline variables	Overall N = 2644
Sex, n (%)
Female	1826 (69.1)
Age (years)
Mean (SD)	39.19 (11.29)
Median (range)	38.30 (16.2; 83.0)
First injection type, n (%)
Titrated	843 (31.9)
Untitrated	1801 (68.1)
First injection depth, n (%)
4 mm	6 (0.2)
6 mm	323 (12.2)
8 mm	751 (28.4)
10 mm	1564 (59.2)
Country, n (%)
Argentina	21 (0.8)
Austria	70 (2.6)
Belgium	29 (1.1)
Canada	221 (8.4)
Chile	322 (12.2)
Colombia	216 (8.2)
Finland	5 (0.2)
France	129 (4.9)
Germany	12 (0.5)
Greece	37 (1.4)
Hungary	27 (1.0)
Israel	24 (0.9)
Italy	769 (29.1)
The Netherlands	268 (10.1)
Portugal	161 (6.1)
Spain	14 (0.5)
Sweden	10 (0.4)
Switzerland	35 (1.3)
Taiwan	22 (0.8)
UK	66 (2.5)
Missing	186 (7.0)

SD, standard deviation.

Figure 1. Patient adherence over 36 months.

Table 2. Average adherence to, and duration of persistence with, the RebiSmart® device by category.

	Adherence, %	Persistence, years
Sex, mean±SD
Male	91.5 ± 17.8	1.44 ± 1.06
Female	91.8 ± 17.4	1.31 ± 1.06
Age, mean±SD
<30 years	92.5 ± 16.3	1.13±.95
≥30–<40 years	92.0 ± 16.0	1.30 ± 1.03
≥40–<50 years	91.8 ± 18.5	1.45 ± 1.10
≥50 years	90.2 ± 20.0	1.60 ± 1.13
First injection type, mean±SD
Titrated	95.1 ± 14.0	1.06±.94
Untitrated	90.1 ± 18.8	1.49 ± 1.09
First injection depth, mean±SD
4–6 mm	86.4 ± 22.0	1.35±.97
8 mm	91.9 ± 16.3	1.28 ± 1.06
10 mm	92.7 ± 16.9	1.39 ± 1.08

SD, standard deviation.

Table 3. Multivariate analyses of the association of sex, age, injection type, and injection depth with rates of adherence to, and duration of persistence with, the RebiSmart® device.

	Adherence		Persistence
	Odds ratio	P value	Hazard ratio	P value
Male vs female	0.97	0.7810	0.8841	0.0078
≥30–<40 vs <30 years	1.09	0.5136	0.8873	0.0384
≥40–<50 vs <30 years	1.27	0.0876	0.7679	<0.0001
≥50 vs <30 years	0.98	0.9141	0.6725	<0.0001
Titrated vs untitrated	1.39	0.0037	1.4712	<0.0001
4–6 mm vs 10 mm	0.53	<0.0001	1.0233	0.7386
8 mm vs 10 mm	0.90	0.3405	1.0165	0.7417

An odds ratio > 1 indicates a higher proportion of patients with normal adherence (>80%) in the respective category compared to the reference category. A hazard ratio > 1 indicates a lower duration of persistence of patients in the respective category as compared to the reference category. Significant values are shown in bold.

Figure 2. Persistence probabilities over 3 years, according to A) Age, B) Sex, C) First injection type, and D) First injection depth.

Table

Author	Contribution
	Concept or design of the study	Acquisition of data	Analysis of data	Data interpretation
Francesco Piras	X	X	X	X
Lilian Arnaud	X	X	X	X
Eric Henninger			X	X
Matthew Keiser	X			X
Andrea Seitzinger	X		X	X
Dominic Jack	X			X
Quentin Le Masne	X			X

Data availability statement

Any requests for data by qualified scientific and medical researchers for legitimate research purposes will be subject to Merck’s Data Sharing Policy. All requests should be submitted in writing to Merck’s data sharing portal https://www.merckgroup.com/en/research/our-approach-to-research-and-development/healthcare/clinical-trials/commitment-responsible-data-sharing.html. When Merck has a co-research, co-development, or co-marketing or co-promotion agreement, or when the product has been out-licensed, the responsibility for disclosure might be dependent on the agreement between parties. Under these circumstances, Merck will endeavor to gain agreement to share data in response to requests.