A discrete choice experiment to determine patient preferences for injection devices in multiple sclerosis

Figures & data

Table

Ease of use:	• Device requires assembly. Medication requires reconstitution.
	• Device requires assembly. Medication is pre-mixed.
	• Device needs no assembly. Medication is pre-mixed.
Comfort of use:	• I cannot adjust any aspects of the injection. The device uses a large needle which is uncomfortable.
	• I cannot control the speed of injection and the device injects the treatment quite rapidly. The device uses a very small needle and I can partially control the depth of injection.
	• The injection is more comfortable because the needle and injection speed are adjustable. The device uses a very small needle and I can easily control the depth of injection.
Reminders:	• No reminders.
	• Provides reminders.
	• Records time and provides reminders.
Needle visibility:	• Visible the entire time.
	• Visible but protected by guard.
	• Cannot be seen.
Practicality:	• Large device. Requires sharps bin and medication needs refrigeration.
	• Quite large device. No sharps bin necessary and can be stored at room temperature.
	• Compact device. No sharps bin necessary and can be stored at room temperature.
Disability:	• Your condition progresses two levels on the MS Disability Scale.
	• Your condition progresses one level on the MS Disability Scale.
	• Your condition remains stable on the MS Disability Scale.

Table 1. Socio-demographic and clinical information.

Demographic and clinical information	n = 99
Gender
Male	29 (29.3%)
Age
Mean (SD)	41.90 (7.98)
Ethnicity
White	96 (97%)
Non-white	3 (3%)
Highest level of education completed
No formal qualifications	6 (6.1%)
Completed university	36 (36.4%)
Employment status
Employed, full or part time	44 (44.4%)
Employed, currently on long-term sick-leave	5 (5.1%)
Disabled	25 (25.3%)
How long have you been diagnosed with MS?
<10 years	75 (75.8%)
>10 years	24 (24.2%)
How long have you been injecting DMD for?
<5 years	60 (60.7%)
5 years or more	39 (39.3%)
Current medications
Avonex	17 (17.2%)
Betaferon	12 (12.1%)
Copaxone	39 (39.4%)
Rebif	28 (28.3%)
Self-reported quality-of-life
Mean EQ-5D score (SD)	0.58 (0.29)
Mean VAS sore (SD)	63.72 (19.76)
Self-reported level of disability (MS disability scale)
No problems or limitations	8 (8.1%)
Mild symptoms	11 (11.1%)
Noticeable symptoms	15 (15.2%)
Symptoms plus limit on activities	7 (7.1%)
MS interferes with activities	15 (15.2%)
Can walk 100–200 m	25 (25.3%)
Requires stick/crutch	10 (10.1%)
Requires 2 canes/crutches	6 (6.1%)
Wheelchair main form of mobility	2 (2%)
Restricted to bed or chair	0 (0%)
Bedridden	0 (0%)

Table 2. Results of mixed logit model of patient preference for injection devices for MS.

Variables	Odds ratios	CI	Coefficients, Mean (SD)	Significance (p)
Ease of use (reference: Easy: no assembly or reconstitution)
Moderate: Assembly required, injection pre-mixed	0.823	0.660–1.026	−0.194 (0.022)	0.084 (0.916)
Hard: Assembly and reconstitution required	0.484	0.363–0.645	−0.726 (0.544)	0.000 (0.002)
Comfort of use (reference: Good, injection more comfortable, speed adjustable, depth easily controllable, very small needle)
Moderate: Speed not controllable, depth partially controllable, very small needle	0.689	0.551–0.860	−0.373 (0.034)	0.001 (0.905)
Poor: No aspect adjustable, large and uncomfortable needle	0.251	0.171–0.367	−1.383 (1.142)	0.000 (0.000)
Reminders (reference: No reminders)
Reminder only	1.313	1.012–1.704	0.272 (0.341)	0.040 (0.084)
Records time and provide reminders	1.499	1.171–1.919	0.405 (0.017)	0.001 (0.929)
Needle visibility (reference: Cannot be seen)
Visible but protected	0.993	0.795–1.240	−0.007 (0.041)	0.950 (0.784)
Always visible	0.691	0.537–0.889	−0.370 (0.117)	0.004 (0.550)
Practicality (reference: Compact device, no bin or refrigeration)
Large device, bin and refrigeration required	0.632	0.492–0.813	−0.458 (0.062)	0.000 (0.766)
Quite large device, no bin or refrigeration required	0.810	0.648–1.012	−0.211 (0.034)	0.064 (0.871)
Disability (reference: stable condition)
Progresses by one level on MS scale	0.117	0.067–0.204	−2.145 (2.148)	0.000 (0.000)

Table 3. Participants’ current injection devices and level of disability.

Injection device questions	Description of level	n = 99 (%)
Ease of use
Easy	‘My injection device does not need to be assembled prior to the injection. The medication is pre-mixed in a cartridge. An electronic device inserts the needle’	33 (33.3%)
Moderate	‘My injection device needs to be assembled before I can inject myself. The medication is pre-mixed in a cartridge’	59 (59.6%)
Hard	‘My injection device needs to be assembled before I can inject myself. The medication has to be mixed with water to reconstitute it before it can be injected. The medication is injected manually’	7 (7.1%)
Comfort of use
Good	‘The injection is more comfortable because the needle and injection speed are adjustable. The device uses a very small needle and I can easily control the depth of injection’	34 (34.4%)
Moderate	‘I cannot control the speed of injection and the device injects the treatment quite rapidly. The device uses a very small needle and I can partially control the depth of injection’	53 (53.5%)
Poor	‘I cannot adjust any aspects of the injection. The device uses a large needle which is uncomfortable’	12 (12.1%)
Reminders
Records and reminders	‘My injection device records time of last injection and provides a reminder’	14 (14.1%)
Doesn’t record but gives reminders	‘My injection device doesn’t record time of last injection but does provide a reminder of when the next injection is due’	4 (4%)
No reminders and doesn’t record	‘My injection device doesn’t provide any reminders’	81 (81.8%)
Needle visibility
Can't be seen	‘Needle cannot be seen’	46 (46.5%)
Visible but protected	‘Needle is visible but protected by a guard’	31 (31.3%)
Visible	‘Needle is visible the whole time’	22 (22.2%)
Practicality
Device compact	‘Device is compact, no sharps bin and can be stored out of the fridge’	14 (14.1%)
Device large but no sharps bin needed	‘Device is quite large, but does not require a sharps bin and can be stored out of the fridge’	7 (7.1%)
Device large and need sharps bin	‘Device is large. You also need a sharps bin and the medication needs to be kept cool’	78 (78.8%)