Usability of a new disposable autoinjector platform device: results of a formative study conducted with a broad user population

Figures & data

Figure 1 The YpsoMate™ disposable autoinjector used in the study.

Figure 2 Tasks performed by the user during an injection.

Table 1 Definition of the user groups and screening criteria for each group

Group	Definition (abbreviation)	Property	Screening criteria and target composition	Target size
Group 1	Health care professionals (HCP)	Healthy qualified user	Registered nurses, diabetes specialist nurses	9
Group 2	Caregivers (CG)	Lay user	Healthy adult fit to administer injections. No particular experience or training	9
Group 3	Diabetics with retinopathy (DR)	Impaired vision	Approximately 50% pen users and the rest non-pen users (eg, people who use infusion sets, syringes, or oral medication)	9
Group 4	Diabetics with neuropathy (DN)	Impaired tactile perception	Approximately 50% pen users and the rest non-pen users (eg, people who use infusion sets, syringes, or oral medication)	9
Group 5	Patients with arthritis (AR)	Impaired dexterity	Male-to-female ratio approximately 1:2. Approximately 50% with pen experience, remainder without device experience	9
All groups		Age	Between 18 and 70 years of age
		Education	Some education expected
		Cognitive skills	Cognitive capabilities to understand and follow the instructions for use after the device has been explained to them

Figure 3 Sequence of events during the handling tests.

Abbreviation: IFU, instructions for use.

Table 2 Participant characteristics

Group	N	Sex	Age	Handedness	Pen experience	Self-reported impairments
1. Health care professionals (HCP)	10	9 female, 1 male	38–54, mean 45	1 left-handed, 9 right-handed	6 naïve, 4 experienced	None
2. Caregivers (CG)	9	6 female, 3 male	19–52, mean 37	1 left-handed, 8 right-handed	6 naïve, 3 experienced	1 with arthritis, 1 with vision impairment, 1 with dyslexia, 6 without impairments
3. Diabetics with retinopathy (DR)	8	6 female, 2 male	34–76, mean 59	1 left-handed, 7 right-handed	4 naïve, 4 experienced	All reported some degree of blurriness of vision in one or both eyes
4. Diabetics with neuropathy (DN)	8	5 female, 3 male	22–83, mean 51	1 left-handed, 7 right-handed	1 naïve, 7 experienced	1 with blurred vision, 2 with tenderness in hands, 2 with pins and needles in hands, 2 with numbness in hands, 1 without any impairments
5. Patients with arthritis (AR)	8	7 female, 1 male	43–70, mean 58	0 left-handed, 8 right-handed	6 naïve, 2 experienced	All reported varying degrees of stiffness, soreness, and numbness in fingers, hands, and wrists
Overall	43	33 female, 10 male	19–83, mean 49	4 left-handed, 39 right-handed	23 naïve, 20 experienced	26 with impairments, 17 without impairments

Figure 4 Observed injection success rates for the first and second injection, per user group.

Note: An injection was deemed successful when all user tasks could be completed by the participant without any assistance.
Abbreviations: HCP, health care professionals; CG, caregivers; DR, diabetics with retinopathy; DN, diabetics with neuropathy; AR, patients with arthritis.

Figure 5 Reported degree of confidence when using the YpsoMate™; number of participants who “strongly agreed” or “agreed” that they felt confident when using the YpsoMate™.

Note: The “strongly agree” and “agree” ratings are the two highest ratings on the 5-point scale.
Abbreviations: HCP, health care professionals; CG, caregivers; DR, diabetics with retinopathy; DN, diabetics with neuropathy; AR, patients with arthritis.

Figure 6 Reported degree of comfort in using the YpsoMate™; number of participants who rated their comfort in using the YpsoMate™ as “very comfortable” or “comfortable”.

Notes: The “very comfortable” and “comfortable” ratings are the two highest ratings on the 5-point scale. The three participants who did not rate the YpsoMate™ as either “very comfortable” or “comfortable” to use, all rated the degree of comfort as “neutral” (the third rating on the 5-point scale).
Abbreviations: HCP, health care professionals; CG, caregivers; DR, diabetics with retinopathy; DN, diabetics with neuropathy; AR, patients with arthritis.

Figure 7 Reported degree of comprehensibility of the IFU; number of participants who rated the IFU as “very easy to understand” or “easy to understand”.

Note: The “very easy to understand” and “easy to understand” ratings are the two highest ratings on the 5-point scale.
Abbreviations: IFU, instructions for use; HCP, health care professionals; CG, caregivers; DR, diabetics with retinopathy; DN, diabetics with neuropathy; AR, patients with arthritis.

Figure 8 Reported degree of comprehensibility of the training; number of participants who rated the training as “very easy to understand” or “easy to understand”.

Note: The “very easy to understand” and “easy to understand” ratings are the two highest ratings on the 5-point scale.
Abbreviations: HCP, health care professionals; CG, caregivers; DR, diabetics with retinopathy; DN, diabetics with neuropathy; AR, patients with arthritis.

Table 3 Observed use errors per user group and injection

User task	HCP (n=10)		CG (n=9)		DR (n=8)		DN (n=8)		AR (n=8)		Total (n=43)
	1st	2nd	1st	2nd	1st	2nd	1st	2nd	1st	2nd	1st	2nd
1. Remove protective cap											0	0
2. Place autoinjector on injection pad						1					0	1
3. Push autoinjector down, first click signals start of injection											0	0
4. Hold autoinjector until second click signals end of injection											0	0
5. Continue holding autoinjector for 5 seconds	2	3	2	3	1		2	4	2	3	9	13
6. Remove autoinjector											0	0
7. Dispose of autoinjector											0	0
Sum over all steps	2	3	2	3	1	1	2	4	2	3	9	14
Rate (occurrence/n)	0.20	0.30	0.22	0.33	0.13	0.13	0.25	0.5	0.25	0.38	0.21	0.33
Number of injections performed without any error, n (%)	8 (80%)	7 (70%)	7 (78%)	6 (67%)	7 (88%)	7 (88%)	6 (75%)	4 (50%)	6 (75%)	5 (63%)	34 (79%)	29 (67%)

Notes: A user error is defined as an event which could potentially lead the participant to fail at a user task. No participant made more than one error during any single injection.

Abbreviations: HCP, health care professionals; CG, caregivers; DR, diabetics with retinopathy; DN, diabetics with neuropathy; AR, patients with arthritis.

Table 4 References to IFU per user group and injection

User task	HCP (n=10)		CG (n=9)		DR (n=8)		DN (n=8)		AR (n=8)		Total (n=43)
	1st	2nd	1st	2nd	1st	2nd	1st	2nd	1st	2nd	1st	2nd
1. Remove protective cap	3					1	1		1		5	1
2. Place autoinjector on injection pad					1		1		4		6	0
3. Push autoinjector down, first click signals start of injection											0	0
4. Hold autoinjector until second click signals end of injection					2	1		1			2	2
5. Continue holding autoinjector for 5 seconds					4	2	1		1		6	2
6. Remove autoinjector											0	0
7. Dispose of autoinjector					1	1			3		4	1
Sum over all steps	3	0	0	0	8	5	3	1	9	0	23	6
Rate (occurrence/n)	0.30	0	0	0	1.00	0.63	0.38	0.13	1.13	0	0.53	0.14

Abbreviations: IFU, instructions for use; HCP, health care professionals; CG, caregivers; DR, diabetics with retinopathy; DN, diabetics with neuropathy; AR, patients with arthritis.

Table 5 Time required to complete the injections

User group	First injection (s)		Second injection (s)
	Mean	Range	Mean	Range
HCP (n=10), injection into mannequin	35.5	19–47	26.1	17–39
CG (n=9), injection into mannequin	28.6	16–57	22.6	14–29
DR (n=8), injection into pad	34.1	19–56	22.6	20–30
DN (n=8), injection into pad	53.0	20–203	21.8	14–40
AR (n=8), injection into pad	32.8	17–66	19.9	13–38
Total (n=43)	34.2	17–203	21.0	13–40

Abbreviations: HCP, health care professionals; CG, caregivers; DR, diabetics with retinopathy; DN, diabetics with neuropathy; AR, patients with arthritis.