Disutility

Disutility represents a decrement in utility (valued quality of life) caused by a specific symptom or complication. These values are often expressed negatively to reflect the impact of the symptom or disease. Disutilities may be derived by subtracting the utility of a health state that includes the symptom or complication to an otherwise identical health state without it. Disutilities may be combined (typically using multiplicative methods, although additive measures may be used) to provide a combined value of their collective impact on a patient’s quality of life. As with all utility values, combining disutilities must be conducted with care because there are scenarios where disutility (A+B) ≠ (disutility (A) + disutility (B)) when the individual and combined health states are valued independently.