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 assess ments 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 in dividual's rank-order preferences. 101 persons with type 2 diabetes provided prefer ence 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 treat ment 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 coef ficients 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 re mains unknown. Key words: individual preferences; diabetes; treatment paths; QALYs. (Med Decis Making 1999;19:113-121)