Best-worst scaling preferences among patients with well-controlled epilepsy: novel questionnaire development

Abstract Background Epilepsy is a common, serious condition characterized by an increased risk for seizures. Fortunately, seizure risk decreases with increasing seizure-free time on antiseizure medications (ASMs). Eventually, patients may consider whether to stop ASMs, which requires weighing treatment benefit versus burden. We developed a novel questionnaire to quantify patient preferences relevant to ASM decision-making. Methods Respondents rated items relevant to ASM decision-making (e.g., different seizure risks, various side effects, cost) on a Visual Analogue Scale (VAS, rated 0-100) how concerning they would find each item and then repeatedly chose the most and least concerning item from subsets (best-worst scaling, BWS). We pretested with five neurologists, then recruited adults with epilepsy who were seizure-free at least one year. Our primary outcomes were recruitment rate, and qualitative and Likert-based feedback. Secondary outcomes included VAS ratings and best-minus-worst scores (number of times an item was chosen as the most minus number of times an item was chosen as the least concerning). Results Thirty-one of 60 (52%) contacted patients completed the study. Most patients felt VAS questions were clear (28; 90%), easy to use (27; 87%), and assessed preferences well (25; 83%). Corresponding results for BWS questions were 27 (87%), 29 (97%), and 23 (77%). Physicians suggested adding a ‘warmup’ question showing a completed example and simplifying terminology. Patients suggested ways to clarify instructions. Cost, inconvenience of taking medication, and laboratory monitoring were the least concerning items. Cognitive side effects and a 50% seizure risk in the next year were the most concerning items. Twelve (39%) of patients made at least one ‘inconsistent choice’ for example ranking a higher seizure risk as lower concern compared with a lower seizure risk, though ‘inconsistent choices’ represented only 3% of all question blocks. Conclusions Our recruitment rate was favorable, most patients agreed the survey was clear, and we describe areas for survey improvement. ‘Inconsistent’ responses during this development phase may lead us to collapse seizure probability items into a single ‘seizure’ category. Evidence regarding how patients weigh benefits and harms is crucial inform clinical care and guideline development.