Preferences for Outcomes Among Adults with Type 1 Diabetes and Caregivers of Children with Type 1 Diabetes

Figures & data

Table 1 Attributes and Levels

Attribute Description (Description Presented to Adults with Type 1 Diabetes)	Patient Attribute Level Descriptions (Caregiver Description, If Different)
HbA1c (“A1c test result at next appointment”)	Achieve your target A1c (Achieve their target A1c) ½ point above your target A1c (½ point above their target A1c) More than a ½ point above your target A1c (More than a ½ point above their target A1c)
Time in optimal glucose range (“Time in optimal range”)*	Almost all of the day More than half of the day Half of the day
Hypoglycemic events (“Low blood sugar events in an average week”)†	2 to 4 mild-to-moderate low events each week 5 to 7 mild-to-moderate low events each week A serious low event each week and 5 to7 mild-to-moderate low events each week
Hyperglycemic events (“High blood sugar events in an average week”)^‡	2 to 4 high events each week 5 to 7 high events each week A very high event each week and 5 to 7 high events each week
Out-of-pocket cost (“Additional monthly personal treatment cost”)	$30 extra $50 extra $80 extra
Additional time spent managing type 1 diabetes (“Additional time spent managing type 1 diabetes”)	No additional time 30 extra minutes spread out over each day 60 extra minutes spread out over each day

Notes: * Almost all the day was defined as about 22 hours, more than half the day was defined as about 18 hours, and half the day was defined as 12 hours. † Mild-to-moderate low blood sugar event was defined as blood sugar levels between 54 and 69 mg/dL and experiencing one or more early symptom(s) of low blood sugar, including shaking, heart palpitations, anxiety, sweating, and hunger. A serious low blood sugar event was defined as blood sugar levels < 54 mg/dL, but not so low that the respondent might pass out, and experiencing one or more later symptoms of low blood sugar, including confusion, dizziness, headaches, blurred vision, tremors, muscle weakness, numbness, tingling, and cognition problems. ‡ A high blood sugar event was defined as blood sugar levels between 181 and 250 mg/dL and not necessarily accompanied by any noticeable symptoms. A very high blood sugar event was defined as blood sugar levels > 250 mg/dL and possibly experiencing one or more symptoms of very high blood sugar, including extreme thirst, hunger, frequent urination, dry skin, blurred vision, drowsiness/fatigue, nausea, or trouble concentrating.

Abbreviation: A1c, hemoglobin A1c.

Figure 1 Example Choice Questions. (A) Patient Survey, Which treatment option would you choose? (B) Caregiver Survey, Which treatment option would you choose for your child?

Note: The choice tasks shown in these questions represent examples of DCE choices in questions from the survey. An experimental design determined the combination of attributes and levels for each hypothetical treatment and the pairs of hypothetical treatments shown in each question. The experimental design included a total of 36 DCE questions, which were used to create four blocks of nine DCE questions each. Table 1 presents the full range of levels for each attribute.

Abbreviations: A1C, hemoglobin A1c; DCE, discrete-choice experiment.

Figure 2 Preference Weights for (A) Adults With Type 1 Diabetes (N = 300) (B) Caregivers of Children With Type 1 Diabetes (N = 400); Attribute Relative Importance, From Most-Preferred Level to Least-Preferred Level, for (C) Adults With Type 1 Diabetes (N = 300) (D) Caregivers of Children With Type 1 Diabetes (N = 400).

Note: The vertical bars surrounding each mean preference weight and each relative importance weight denote the 95% confidence interval. A mild-to-moderate low blood sugar event was defined as blood sugar levels between 54 and 69 mg/dL and experiencing one or more early symptom(s) of low blood sugar, including shaking, heart palpitations, anxiety, sweating, and hunger. A serious low blood sugar event was defined as blood sugar levels <54 mg/dL, but not so low that a person might pass out, and experiencing one or more later symptoms of low blood sugar, including confusion, dizziness, headaches, blurred vision, tremors, muscle weakness, numbness, tingling, and cognition problems. A high blood sugar event was defined as blood sugar levels between 181 and 250 mg/dL and not necessarily accompanied by any noticeable symptoms. A very high blood sugar event was defined as blood sugar levels >250 mg/dL and possibly experiencing one or more symptoms of very high blood sugar, including extreme thirst, hunger, frequent urination, dry skin, blurred vison, drowsiness/fatigue, nausea, or trouble concentrating.

Abbreviation: A1C, hemoglobin A1c.

Table 2 Willingness to Pay for Improvements in Treatment Outcomes

Improvement	From	To	WTP ($ per Month)	95% CI ($)*
Adults with type 1 diabetes (N = 300)
A1c test result at next appointment	½ point above your target A1c	Achieve your target A1c	5	−3 to 12
	More than a ½ point above your target A1c	½ point above your target A1c	12	4 to 21
	More than a ½ point above your target A1c	Achieve your target A1c	17	7 to 26
Time in optimal range	More than half of the day	Almost all of the day	7	−1 to 15
	Half of the day	More than half of the day	7	−2 to 15
	Half of the day	Almost all of the day	13	4 to 22
Low blood sugar events in an average week	5 to 7 mild-to-moderate low events each week	2 to 4 mild-to-moderate low events each week	22	12 to 31
	A serious low event each week and 5 to 7 mild-to-moderate low events each week	5 to 7 mild-to-moderate low events each week	52	37 to 66
	A serious low event each week and 5 to 7 mild-to-moderate low events each week	2 to 4 mild-to-moderate low events each week	73	55 to 92
High blood sugar events in an average week	5 to 7 high events each week	2 to 4 high events each week	34	23 to 44
	A very high event each week and 5 to 7 high events each week	5 to 7 high events each week	21	12 to 30
	A very high event each week and 5 to 7 high events each week	2 to 4 high events each week	55	40 to 70
Caregivers of children with type 1 diabetes (N = 400)
A1c test result at next appointment	½ point above their target A1c	Achieve their target A1c	<30	−15 to 15
	More than a ½ point above their target A1c	½ point above their target A1c	<30	−7 to 27
	More than a ½ point above their target A1c	Achieve their target A1c	<30	−7 to 26
Time in optimal range	More than half of the day	Almost all of the day	<30	−5 to 29
	Half of the day	More than half of the day	<30	−1 to 35
	Half of the day	Almost all of the day	<30	7 to 50
Low blood sugar events in an average week	5 to 7 mild-to-moderate low events each week	2 to 4 mild-to-moderate low events each week	32	11 to 53
	A serious low event each week and 5 to 7 mild-to-moderate low events each week	5 to 7 mild-to-moderate low events each week	71	37 to 104
	A serious low event each week and 5 to 7 mild-to-moderate low events each week	2 to 4 mild-to-moderate low events each week	>80	56 to 149
High blood sugar events in an average week	5 to 7 high events each week	2 to 4 high events each week	52	26 to 79
	A very high event each week and 5 to 7 high events each week	5 to 7 high events each week	42	19 to 66
	A very high event each week and 5 to 7 high events each week	2 to 4 high events each week	>80	52 to 137

Notes: * The 95% CI is the estimated lower and upper bound for the WTP estimates. When this interval includes zero (the lower bound is negative and the upper bound is positive), the results are not statistically significantly different from zero, indicating that the average respondent is not willing to pay for that improvement. Estimates of WTP beyond the range presented in the survey (eg, estimates greater than $80) should be interpreted with caution. Estimates over $80 indicate a strong preference for the change, but the specific number may not be reliable.

Abbreviations: A1c, hemoglobin A1c; CI, confidence interval; WTP, willingness to pay.

Figure 3 Preference Share Predictions.

Abbreviation: A1c, hemoglobin A1c.