A discrete choice experiment to assess patients’ preferences for HIV treatment in the rural population in Colombia

Figures & data

Table 1. The five attributes and their associated levels.

Attributes	Levels
Effect on life expectancy	Large positive effects: Live many years more
	Moderate positive effects: Live a few more years
	Mild positive effects: Live a short while more (a few months, less than 2 years)
Effect on physical activity	All physical activities without difficulty
	Some physical activities with difficulty
	All physical activities with difficulty
Risk of moderate side-effects	1%: Low risk of side-effects
	2.5%: Medium risk of side-effects
	5%: Higher risk of side-effects
Accessibility to clinic	Less than 2 hours
	Between 2 and 5 hours
	More than 5 hours
Economic costs to access controls	Subsidized travel costs
	Low travel costs, paid by the patient
	High travel costs, paid by the patient

Figure 1. An example of a choice task in English.

Table 2. Patient characteristics.

Characteristic	Mean ± SD	n = 129	%
Age (years)	38.4 ± 12.4
Difficulty (7 Likert scale)	3.6 ± 1.7
Travel time	2:23 ± 1:19
Sex
Male		80	64.0
Female		39	31.2
Other		6	4.8
Education
Primary school		23	18.9
Secondary school		55	45.1
Engineer degree (technologist)		32	26.2
University degree		12	9.8
Sexual preference
Heterosexual		50	42.0
Homosexual		56	47.1
Bisexual		9	7.6
Other		4	3.4
Residence
Bogota (rural)		82	63.5
Outside Bogota		47	36.4

Abbreviation. SD, standard deviation.

Table 3. Results of the random parameter logit model.

Attributes and levels	Coefficient	95% CI	SD	95% CI	Relative importance
Life expectancy (effect)					26.0%
Large positive effects	0.45***	(0.29, 0.61)	0.34***	(0.17, 0.51)
Moderate positive effects	0.05	(−0.06, 0.16)	0.01	(−0.48, 0.51)
Mild positive effects (Ref)	−0.50***	(−0.35, −0.66)
Physical activity (effect)					27.5%
All without difficulty	0.53***	(0.39, 0.68)	0.33***	(0.15, 0.50)
Some with difficulty	−0.06	(−0.17, 0.05)	0.27***	(0.09, 0.44)
All with difficulty (Ref)	−0.47***	(−0.31, −0.63)
Risk of side-effects					16.7%
1% increase in risk	−0.15***	(−0.23, −0.08)	0.13**	(0.02, 0.24)
Accessibility (to clinic)					22.1%
Less than 2 hours	0.31***	(0.18, 0.43)	0.27***	(0.09, 0.45)
Between 2 and 5 hours	0.20***	(0.08, 0.31)	0.27***	(0.10, 0.45)
More than 5 hours (Ref)	−0.50***	(−0.36, −0.65)
Economic costs (access)					7.6%
Subsidized travel costs	0.09	(−0.06, 0.24)	0.48***	(0.31, 0.64)
Low travel costs	0.10*	(−0.01, 0.20)	0.14	(−0.20, 0.48)
High travel costs (Ref)	−0.18**	(−0.02, −0.35)

Abbreviations. CI, confidence interval; SD, standard deviation.

SD values correspond to the random component of the model coefficients. Number of observations = 1,548; Pseudo R-squared = 0.082; Log likelihood = –960.57; Akaike information criterion = 1.29.

*** p < .01, **p < .05, *p < .1.

Table 4. The relative importance of HIV treatment attributes per patient sub-group.

	Estimation of relative importance (%)
	Overall	Age ≤38	Age >38	Low educated	High educated
Life expectancy (effect)	26.0	19.6	34.2	25.1	28.5
Physical activity (effect)	27.5	32.2	22.2	24.1	30.7
Risk of side-effects	16.7	20.1	11.4	10.7	20.4
Accessibility (to clinic)	22.1	20.9	22.2	28.1	13.4
Economic costs (access)	7.6	7.3	10.1	12.0	7.0

Table 5. Results of sub-group analyses for age.

Attributes and levels	Patients aged ≤38		Patients aged >38		p-value
	Coefficient	SD	Coefficient	SD
Life expectancy (effect)
Large positive effects	0.39***	0.33***	0.54***	0.37**	.77
Moderate positive effects	0.10	0.01	0.00	0.25	.38
Mild positive effects (Ref)	−0.49***		−0.54***
Physical activity (effect)
All without difficulty	0.68***	0.21	0.36***	0.39***	.00
Some with difficulty	−0.08	0.35***	−0.02	0.02	.58
All with difficulty (Ref)	−0.60***		−0.34***
Risk of side-effects
1% increase in risk	−0.20***	0.07	−0.09	0.24***	.11
Accessibility (to clinic)
Less than 2 hours	0.32***	0.11	0.28***	0.45***	.44
Between 2 and 5 hours	0.19**	0.23*	0.14	0.20	.68
More than 5 hours (Ref)	−0.51***		−0.42***
Economic costs (access)
Subsidized travel costs	0.09	0.23*	0.08	0.72***	.90
Low travel costs	0.11	0.19	0.12	0.08	.90
High travel costs (Ref)	−0.20		−0.20

Abbreviations. CI, confidence interval; SD, standard deviation.

SD values correspond to the random component of the model coefficients. Number of observations = 780 (≤38) and 708 (>38); Pseudo R-squared = 0.092 (≤38) and 0.106 (>38); Log likelihood = –484 (≤38) and –423 (>38); Akaike information criterion = 1.31 (≤38) and 1.29 (>38).

*** p < .01, **p < .05, *p < .1.

Table 6. Results of sub-group analyses for education.

Attributes and levels	Low educated patients		High educated patients		p-value
	Coefficient	SD	Coefficient	SD
Life expectancy (effect)
Large positive effects	0.35***	0.15	0.99***	0.54***	.03
Moderate positive effects	0.03	0.18	0.08	0.04	.50
Mild positive effects (Ref)	−0.40***		−1.07***
Physical activity (effect)
All without difficulty	0.40***	0.04	1.05***	0.86***	.01
Some with difficulty	−0.08	0.23*	0.07	0.51***	.36
All with difficulty (Ref)	−0.32***		−1.12***
Risk of side-effects
1% increase in risk	−0.08*	0.00	−0.37***	0.40***	.02
Accessibility (to clinic)
Less than 2 hours	0.36***	0.25*	0.23*	0.52***	.23
Between 2 and 5 hours	0.12*	0.37***	0.37***	0.00	.13
More than 5 hours (Ref)	−0.48***		−0.60***
Economic costs (access)
Subsidized travel costs	0.17**	0.49***	−0.15	0.01	.11
Low travel costs	0.02	0.27**	0.36***	0.04	.03
High travel costs (Ref)	−0.19**		−0.21

Abbreviations. CI, confidence interval; SD, standard deviation.

SD values correspond to the random component of the model coefficients. Number of observations = 936 (LowE) and 528 (HighE); Pseudo R-squared = 0.072 (LowE) and 0.211 (HighE); Log likelihood = –585 (LowE) and –283 (HighE); Akaike information criterion = 1.33 (LowE) and 1.16 (HighE).

*** p < .01, **p < .05, *p < .1.