Holistic versus composite preferences for lifetime treatment sequences for type 2 diabetes.

This study of patient preferences for lifetime treatment sequences for type 2 diabetes had three objectives: to assess the feasibility of obtaining holistic preference assessments using the time-tradeoff (TTO) technique; to compare composite and holistic preference scores for the same lifetime treatment paths; and to assess the validity of composite and holistic preference measures in terms of their congruence with an individual's rank-order preferences. 101 persons with type 2 diabetes provided preference ratings for hyperglycemic treatments lasting 30 years, including eight discrete treatment states and four treatment paths. Scenarios described drug and glucose-testing regimens, efficacy of glucose control, and side effects. After ranking and rating scenarios on a thermometer scale, subjects provided TTO preferences for each treatment state or path scenario. Holistic assessment of treatment paths was feasible with the TTO technique, in terms of useable data (88% of interviews) and effect on coefficients of variation. Holistic and composite preference scores were not statistically different. Agreement was poor between rankings implied by holistic and composite scores and direct rankings. The authors conclude that lifetime treatment paths with minor differences in health effects can be assessed using either composite (QALY) or holistic (HYE) measures. The validity of these TTO-based preference measures remains unknown.