A discrete choice experiment evaluation of patients’ preferences for different risk, benefit, and delivery attributes of insulin therapy for diabetes management

Figures & data

Table 1 Sociodemographic and diabetes-related characteristics of participants (n = 274)

Characteristic	Number (%) or mean (SD)
Mean age	56.7 (12.98)
Gender
Male	144 (52.55)
Female	130 (47.45)
Most recent HbA1c level
4%–7%	103 (37.59)
7.1%–10%	125 (45.62)
>10%	24 (8.76)
Do not know	18 (6.57)
Number of hypoglycemic events (per month)a
None	113 (41.24)
1–2	64 (23.36)
3–4	48 (17.52)
5–6	23 (8.39)
7–8	13 (4.74)
>8	9 (3.28)
Type of diabetes
Type 1	47 (17.15)
Type 2	227 (82.85)
Insulin statusb
Insulin users	134 (48.91)
Insulin nonusers	139 (50.73)
Highest education level completed
Some high school	30 (10.95)
Completed high school	66 (24.09)
Trade/technical college	92 (33.58)
University	60 (21.89)
Masters or doctorate degree	18 (6.57)
Annual income by categories (C$):
Low (<20,000)	33 (12.04)
Medium (20,001–50,000)	74 (27.01)
High (≥50,001)	120 (43.80)

a Notes: 4 missing;

b 1 missing.

Abbreviation: SD, standard deviation.

Table 2 Relative preferences – full conditional logit model (n = 274)a

Treatment attributes	Regression coefficient (SE)b
Fasting blood glucose control
Optimal	0.581 (0.032)
Suboptimal	0.121 (0.027)
Poor	−0.702 (0.034)
Number of hypoglycemia events per month
None	0.243 (0.030)
4	0.053 (0.027)d
8	−0.296 (0.031)
Weight gain in the first year
Low (2 kg)	0.272 (0.030)
Moderate (6 kg)	0.143 (0.028)
High (10 kg)	−0.416 (0.031)
Route of administration for the long-acting insulin
Oral	0.054 (0.017)
Subcutaneous	−0.054 (0.017)c
Route of administration for the short-acting insulin
Subcutaneous	−0.171 (0.031)
Inhaled	0.014 (0.029)e
Oral	0.156 (0.028)
Cost	−0.004 (0.000)

a Notes: Log likelihood function: −2484; McFadden’s log-likelihood ratio: 0.123;

b SE: standard error;

b P < 0.001, except as noted;

c P = 0.002;

d P = 0.053;

e P = 0.612

Abbreviation: SE, standard error.

Table 3 Relative preferences – segmented model: insulin users vs insulin naïve

Treatment attributes	Insulin users	Insulin naïve	z-test (users × naïve)
	Regression coefficient (SE)	Regression coefficient (SE)	P value
Fasting glucose control
Optimal	0.662 (0.049)	0.535 (0.045)	0.055
Suboptimal	0.109 (0.039)	0.135 (0.038)	0.635
Poor	−0.772 (0.052)	−0.670 (0.048)	0.151
Number of hypoglycemia events per month
None	0.341 (0.047)	0.183 (0.042)	0.012
4	0.031 (0.039)	0.067 (0.039)	0.518
8	−0.372 (0.047)	−0.250 (0.044)	0.057
Weight gain in the first year
Low (2 kg)	0.316 (0.044)	0.249 (0.043)	0.278
Moderate (6 kg)	0.170 (0.041)	0.130 (0.039)	0.479
High (10 kg)	−0.486 (0.047)	−0.380 (0.042)	0.092
Route of administration for the long-acting insulin
Oral	−0.042 (0.025)	0.146 (0.024)	<0.001
Subcutaneous	0.041 (0.025)	−0.146 (0.024)	<0.001
Route of administration for the short-acting insulin
Subcutaneous	0.002 (0.044)	−0.344 (0.045)	<0.001
Inhaled	−0.083 (0.042)	0.119 (0.041)	<0.001
Oral	0.081 (0.042)	0.225 (0.040)	0.013
Cost	−0.004 (0.000)	−0.005 (0.000)	0.918

Abbreviation: SE, standard error.

Table 4 Relative preferences – segmented model: type 1 vs type 2 diabetes

Treatment attributes	Type 1 diabetes	Type 2 diabetes	z-test (type 1 × type 2)
	Regression coefficient (SE)	Regression coefficient (SE)	P value
Fasting glucose control
Optimal	0.937 (0.095)	0.527 (0.035)	<0.001
Suboptimal	0.262 (0.070)	0.100 (0.029)	0.034
Poor	−1.199 (0.105)	−0.627 (0.037)	<0.001
Number of hypoglycemia events per month
None	0.409 (0.088)	0.226 (0.033)	0.051
4	−0.046 (0.072)	0.066 (0.030)	0.154
8	−0.363 (0.088)	−0.291 (0.034)	0.449
Weight gain in the first year
Low (2 kg)	0.340 (0.084)	0.269 (0.033)	0.438
Moderate (6 kg)	0.20 (0.076)	0.142 (0.030)	0.505
High (10 kg)	−0.537 (0.091)	−0.412 (0.033)	0.195
Route of administration for the long-acting insulin
Oral	−0.057 (0.046)	0.075 (0.019)	0.008
Subcutaneous	0.057 (0.046)	−0.075 (0.019)	0.008
Route of administration for the short-acting insulin
Subcutaneous	0.041 (0.082)	−0.219 (0.034)	0.003
Inhaled	−0.097 (0.078)	0.037 (0.032)	0.109
Oral	0.056 (0.077)	0.182 (0.031)	0.131
Cost	−0.003 (0.000)	−0.005 (0.000)	0.269

Abbreviation: SE, standard error.