The systematic development of attributes and levels for a discrete choice experiment of HIV patient preferences for long-acting antiretroviral therapies in the United States

Table 1 Feasible restrictions placed on attributes and levels for each mode of treatment

Attribute	Levels	Restrictions by mode of administration
Attribute	Levels	LA Oral	SC injection	IM injection	Implant	All modes
Mode	LA Oral, SC Injection, IM Injection, Implant*
Frequency	1, 4, 8, 12, 26, 52 weeks	1 or 4 weeks	1, 4, 8, or 12 weeks	4, 8, or 12 weeks	26 or 52 weeks	IF location = clinic or pharmacy, THEN dose frequency ≥ 4
Location	Home, pharmacy, clinic	Only home	Any	Not home	Only clinic	IF frequency = 1 week, THEN location = home
Pain	None, mild, moderate	Only none	None or mild	Mild or moderate	Mild or moderate
Oral lead-in	0, 3, 6 months
Negative reaction testing	Yes or no
Late dose leeway	Short, long*

^*Long-acting oral tablet, subcutaneous injection, intramuscular injection
^*Short vs Long: For the late dose leeway attribute, the duration of time displayed to respondents for both the "short" and "long" levels was dependent on the dosing frequency of that alternative

ISSN: 1742-6405