The Q-TWiST approach to assessing health-related quality of life in epilepsy.

We propose to develop a methodology for evaluating clinical interventions for epilepsy in terms of their effects on disease-related outcomes, social cost and quality of life, while incorporating patient preference. The technique represents an extension of the 'quality-adjusted time without symptoms and toxicities' (Q-TWiST) method, which has been previously used to evaluate treatments for cancer and AIDS with respect to their costs in terms of toxicities, and benefits in terms of improved progression-free and overall survival. The extensions we propose to develop allow additional dimensions of quality of life relevant to epilepsy to be included in the analysis. We demonstrate a possible application of the proposed Q-TWiST method with a hypothetical example comparing surgery vs antiepileptic medication management alone for seizure control. The trade-offs between these alternative treatments are highlighted, along with patient importance weightings regarding various dimensions of quality of life. We describe further research needed to develop the methodology fully and comment on its potential usefulness.