Facilitating and understanding the family's choice of injection device for growth hormone therapy by using conjoint analysis

Background: Conjoint analysis involves the measurement of consumer preferences between choice alternatives. Aims and objectives: To investigate the use of conjoint analysis in facilitating and understanding choice of growth hormone injection devices. Method and subjects: 56 patients and their parents participated in an electronic, computer-based interview. The interview took a median time of 18 min (range 12-30) and allowed an immediate matching of injection devices to the family's preferences. Results: Amongst the key drivers of choice, lack of bruising was rated highest and designated an index of 100. Compared to this, the remaining attributes in order of desirability were: auto-injector (98), lack of pain (93), lightweight (88), silent (82), ready-mixed (77), ease of holding (69), telephone helpline (66), needle-free (62), small size (60), nurse support (47), hidden needle (45), stored in fridge (13) and home delivery (6). Out of the 17 families who had already chosen a device previously by discussion with the clinic nurse, the computer model placed their device either as first or second out of seven devices tested. Conclusion: Adaptive or interactive conjoint analysis applied at the patient level can facilitate the choice-making process whilst providing an insight into the relative importance of the key features that influence choice.