Design and validation of a bedside decision instrument to elicit a patient's preference concerning allogenic bone marrow transplantation in chronic myeloid leukemia

The objective of this study was to design and validate a bedside decision instrument to be used by patients with chronic myeloid leukemia and their physicians in deciding between the therapeutic alternatives of bone marrow transplantation and conservative management during the early phase of disease. A decision board was constructed containing detailed scenarios associated with the treatment alternatives, together with estimates of survival probabilities at various periods of followup. The instrument was tested on 42 healthy hospital personnel and validated by measuring the extent to which systematic alterations in the scenarios with respect to toxicities and survival probabilities produced predicted shifts in treatment preferences. A subgroup of respondents was randomized to receive information through the decision board alone or a shorter and less informative version of the instrument, followed by the decision board. The direction and strength of stated preferences were compared, together with satisfaction for these preferences. The direction and strength of preferences between bone marrow transplantation or conservative chemotherapy were influenced in a predictable way by changes in the toxicity and survival descriptions in the scenarios. Using the test-retest method in 16 subjects, the stated preferences were found to be highly reliable (intraclass correlation coefficient, 0.87). The mean level of satisfaction with the stated preference, on a scale from not at all satisfied = 1 to very satisfied = 5, was higher for those exposed to the decision board (3.7, SD 1.06) compared with those presented with the short version (2.95, SD 0.67) (P < 0.01). The results demonstrate the feasibility and acceptability of the instrument in healthy individuals. The preferences elicited by the instrument appear to be reliable and valid according to prespecified constructs of the relation between the information provided and the preferences predicted. These results support further testing of this approach in actual patients.