Preferences of people living with HIV for injectable and oral antiretroviral treatment in the Netherlands: a discrete choice experiment

Figures & data

Table 1. Attributes and levels of oral and long-acting injectable ART.

	Oral tablet	Long-acting injection
Location of administration	1. At home	1. At hospital
		2. At home given by a nurse
Dosing frequency	1. One pill every day	1. Two injections at the same visit every month
	2. Two pills every day	2. Two injections at the same visit every 2 months
Risk of short-term side effects for a few days	1. 20 out of 100 (20%) people will experience mild to moderate side effects, nausea, fatigue and/or headaches	1. 20 out of 100 people (20%) will experience mild to moderate side effects, injection site reaction (such as rush or redness), fatigue and/or headaches
	2. 15 out of 100 (15%) people will experience mild to moderate side effects, nausea, fatigue and/or headaches	2. 15 out of 100 people(15%) will experience mild to moderate side effects, injection site reaction (such as rush or redness), fatigue and/or headaches
	3. 10 out of 100 (10%) people will experience mild to moderate side effects, nausea, fatigue and/or headaches	3. 10 out of 100 people (10%) will experience mild to moderate side effects, injection site reaction (such as rush or redness), fatigue and/or headaches
Drug–drug interaction (A change in a drug's effect on the body when the drug is taken together with a second drug)	1. 10 out of 100 (10%) people will experience drug-drug interaction
	2. 15 out of 100 (15%) people will experience drug-drug interaction
	3. 20 out of 100 (20%) people will experience drug-drug interaction
Forgivability (if dose missed)	1. 0 d (a few hours) of forgivability after missing dose	1. One week of forgivability after missing dose
		2. Two weeks of forgivability after missing dose
Food and mealtime restrictions	1. None	1. None
	2. Take with food
	3. Take on an empty stomach

Figure 1. Example of a choice task in the discrete choice experiment.

Table 2. Demographic and disease characteristics of respondents and comparison of the respondents always choosing oral, long-acting injectable and with variable choice in the choice tasks of the discrete choice experiment.^†

	n	All respondents (n = 76)	n	Always oral (n = 22)	n	Always long-acting injection (n = 30)	n	Variable choice (n = 24)	p-value^‡	p-value^§
Sex	71		17		30		24		0.57	0.43*
Male		60 (84.5%)		13 (76.5%)		26 (86.7%)		21 (87.5%)
Age median (Q1–Q3)	71	51.0 (43.0–58.0)	17	50.0 (46.5–59.5)	30	50.5 (39.8–57.3)	24	52.0 (39.5–58.8)	0.63	0.90
Education	72		18		30		24		0.45	0.43
Lower		30 (41.7%)		6 (33.3%)		17 (56.7%)		7 (29.2%)
Higher		42 (58.3%)		12 (66.6%)		13 (43.3%)		17 (70.8%)
Work status	72		18		30		24		0.79	0.76
Full time (>32 h per week)		25 (34.7%)		5 (27.8%)		10 (33.3%)		10 (42.0%)
Part time (<32 h per week)		13 (18.0%)		4 (22.2%)		6 (20.0%)		3 (13.0%)
Unemployed		25 (34.7%)		8 (44.4%)		10 (33.3%)		7 (29.0%)
Student and part-time paid work		1 (1.4%)		1 (5.6%)		4 (13.3%)		1 (4.00%)
Other		8 (11.1%)		0 (0.0%)		0 (0.0%)		3 (13.0%)
Country of birth	70		16		30		24		0.37	0.40
Netherlands		58 (82.9%)		13 (81.3%)		23 (76.7%)		22 (91.7%)
Other European country		8 (11.4%)		3 (18.8%)		4 (13.3%)		1 (4.2%)
Country outside Europe		4 (5.7%)		0 (0.0%)		3 (10.0%)		1 (4.2%)
HIV positive (yes)	71	71 (100%)	17	17 (100%)	30	30 (100%)	24	24 (100%)	.	.
Years with HIV median (Q1–Q3)	72	13.5 (7.0–25.0)	18	23.0 (11.8–26.0)	30	11.5 (5.8–19.3)	24	12.0 (5.8–30.3)	0.07	0.05
Currently using HIV medication (yes)	72	71 (98.6%)	18	17 (94.4%)	30	30 (100%)	24	24 (100%)	0.022	0.37*
Number of pills per day median (Q1–Q3)	70	1.0 (1.0–2.0)	17	1.0 (1.0–2.0)	29	1.0 (1.0–2.0)	24	1.0 (1.0–1.8)	0.93	0.84
Ever missed doses (yes)	71	46 (64.8%)	17	11 (64.7%)	30	18 (60.0%)	24	17 (70.8%)	0.71	0.75
Number of missed doses per week median (Q1–Q3)	44	0.0 (0.0–0.3)	10	0.0 (0.0–0.6)	17	0.0 (0.0–0.5)	17	0.0 (0.0–3.8)	0.44	0.60
Years on HIV medication median (Q1–Q3)	71	12.0 (7.0–20.0)	17	20.0 (8.0–23.5)	30	10.0 (5.8–15.0)	24	10.3 (5.5–17.5)	0.07	0.05
Experience with injections (yes)	71	63 (88.7%)	17	16 (94.1%)	30	25 (83.3%)	24	22 (91.7%)	0.45	0.40*
Anxiety for needles (0 = not bothered, 10 = try to avoid at all cost) median (Q1–Q3)	71	1.0 (0.0–3.0)	17	1.0 (0.0–4.0)	30	1.0 (0.0–2.0)	24	1.0 (1.0–5.0)	0.055	0.27
Medium to high degree of anxiety		8 (11.3%)		2 (11.8%)		2 (6.7%)		4 (16.7%)	0.51	0.60*
Willingness to switch HIV medication (0 = definitely prepared to switch to 10 = definitely not prepared to switch) median (Q1–Q3)	71	2.0 (1.0–5.0)	17	5.0 (1.5–7.5)	30	1.0 (0.0–2.0)	24	2.0 (1.0–5.0)	0.03	<0.01
Ease of visiting clinic	71		17		30		24		0.56	0.24
Difficult or very difficult		6 (8.4%)		2 (11.8%)		1 (3.3%)		3 (12.5%)
Distance home-clinic (kms) median (Q1–Q3)	69	5.0 (2.0–21.3)	17	15.0 (3.5–40.0)	29	5.0 (3.0–21.0)	23	5.0 (2.0–8.0)	0.08	0.36
Number of other medications median (Q1–Q3)	71	1.0 (0.0–5.0)	17	2.0 (0.5–7.0)	30	2.0 (0.0–5.0)	24	1.0 (0.0–2.8)	0.19	0.87
Comorbidity (yes)	72	26 (36.1%)	18	4 (22.2%)	30	11 (36.7%)	24	11 (45.8%)	0.29	0.35*
Understanding of DCE (0 = understood DCE not at all, 10 = understood DCE completely) median (Q1–Q3)	74	9.0 (7.0–10.0)	20	8.0 (7.0–10.0)	30	9.0 (7.0–10.0)	24	9.5 (9.0–10.0)	0.26	0.95
Ease of completing DCE (0 = very difficult, 10 = very easy) median (Q1–Q3)	74	8.0 (7.0–10.0)	20	8.0 (7.0–10.0)	30	8.0 (6.8–10.0)	24	8.0 (7.3–9.0)	0.98	0.86

^† Categorial variables are expressed in number and frequencies (n (%)), continuous variables are expressed in median (interquartile range (Q1–Q3)).

^‡ p-value of difference between the three groups. For continuous data, because of the non-Gaussian distribution of variables, we applied a Kruskal–Wallis test; for categorial data, we applied a Chi-squared test.

^§ p-value for difference between people living with HIV choosing always “oral” versus people living with HIV choosing always “long-acting injection”. For continuous data, because of the non-Gaussian distribution of variables, we applied a Mann–Witney U test; for categorial data, we applied either a Chi-squared test or a Fisher’s exact test (p-value marked with an *).

Table 3. Results of the mixed logit model.

Attributes and levels	Estimate (95% CI)	Standard deviation
Administration method
Oral	−1.33 (−2.41, −0.26)**	12.89 (7.39, 18.38)***
Long-acting injectable	1.33 (0.26, 2.41)**	–
Location of administration (long-acting injectable)
At hospital	−2.17 (−3.64, −0.71)***	2.63 (1.17, 4.10)***
At home given by a nurse	2.17 (0.71, 3.64)***	–
Dosing frequency
Oral
One pill every day	2.11 (0.55, 3.67)***	3.45 (1.70, 5.21)***
Two pills every day	−2.11 (−3.67, −0.55)***	–
Long-acting injectable
Two injections at the same visit every month	−3.88 (−5.91, −1.84)***	3.92 (1.71, 6.14)***
Two injections at the same visit every two months	3.88 (1.84, 5.91)***	–
Risk of short-term side effects for a few days
Oral
20 out of 100 (20%) people will experience mild to moderate side effects	−2.13 (0.68, 3.58)***	–
15 out of 100 (15%) people will experience mild to moderate side effects	0.40 (−1.01, 1.80)	1.52 (0.21, 2.82)**
10 out of 100 (10%) people will experience mild to moderate side effects	1.73 (0.31, 3.15)**	2.70 (0.03, 5.36)**
Long-acting injectable
20 out of 100 (20%) people will experience mild to moderate side effects	−1.23 (−2.58, 0.12)*	–
15 out of 100 (15%) people will experience mild to moderate side effects	−2.48 (−4.59, −0.36)**	0.07 (−0.90, 1.05)**
10 out of 100 (10%) people will experience mild to moderate side effects	3.71 (1.11, 6.31)***	1.01 (−0.54, 2.55)**
Drug-drug interaction
20 out of 100 (20%) people will experience drug-drug interaction	−2.74 (−4.19, −1.29)***	–
15 out of 100 (15%) people will experience drug-drug interaction	−0.16 (−0.85, 0.52)**	1.75 (0.56, 2.93)***
10 out of 100 (10%) people will experience drug-drug interaction	2.90 (1.48, 4.33)***	2.75 (0.92, 4.58)***
Forgivability (if doses missed) (long-acting injectable)
One week of forgivability after missing dose	−0.17 (−1.36, 1.02)	1.91 (0.32, 3.51)**
Two weeks of forgivability after missing dose	0.17 (−1.02, 1.36)	–
Food and mealtime restrictions
None	0.89 (−0.46, 2.25)	4.02 (2.07, 5.96)***
Take with food	1.25 (−0.11, 2.61)*	3.79 (1.43, 6.16)***
Take on an empty stomach	−2.14 (−3.92,0.32)**	–

*p < 0.10, **p < 0.05, ***p < 0.01.

McFadden Adjusted R2 = 0.6509; Log-likelihood = −220.65.

Table 4. Results of the latent class analysis.

Attributes and levels	Latent class 1	Latent class 2
Administration method
Oral	−4.59***	0.85***
Long-acting injectable	4.59***	−0.85***
Location of administration (long-acting injectable)
At hospital	0.52	−0.44***
At home given by a nurse	−0.52	0.44***
Dosing frequency
Oral
One pill every day	−1.14	0.23*
Two pills every day	1.14	−0.23*
Long-acting injectable
Two injections at the same visit every month	−0.69	−0.42***
Two injections at the same visit every two months	0.69	0.42***
Risk of short-term side effects for a few days
Oral
20 out of 100 (20%) people will experience mild to moderate side effects	−2.09	−0.15
15 out of 100 (15%) people will experience mild to moderate side effects	0.10	0.17
10 out of 100 (10%) people will experience mild to moderate side effects	1.99	−0.02
Long-acting injectable
20 out of 100 (20%) people will experience mild to moderate side effects	−1.33	−0.13
15 out of 100 (15%) people will experience mild to moderate side effects	−0.15	−0.10
10 out of 100 (10%) people will experience mild to moderate side effects	1.48	0.23
Drug-drug interaction
20 out of 100 (20%) people will experience drug-drug interaction	−1.33	−0.10
15 out of 100 (15%) people will experience drug-drug interaction	−1.02	−0.24**
10 out of 100 (10%) people will experience drug-drug interaction	2.35*	0.34***
Forgivability (if doses missed) (long-acting injectable)
One week of forgivability after missing dose	0.79	−0.00
Two weeks of forgivability after missing dose	−0.79	0.00
Food and mealtime restrictions
None	0.05	0.12
Take with food	−2.39	−0.01
Take on an empty stomach	2.34	−0.11
Class probabilities	48.7%	51.3%

*p < 0.10, **p < 0.05, ***p < 0.01.

McFadden Adjusted R2 = 0.5266; Log-likelihood = −299.27.