Development of a core outcome set for quality of life for adults with drug-resistant epilepsy: A multistakeholder Delphi consensus study

Abstract

Objective: In 2017, the American Academy of Neurology (AAN) convened the AAN Quality Measurement Set working group to define the improvement and maintenance of quality of life (QOL) as a key outcome measure in epilepsy clinical practice. A core outcome set (COS), defined as an accepted, standardized set of outcomes that should be minimally measured and reported in an area of health care research and practice, has not previously been defined for QOL in adult epilepsy.

Methods: A cross-sectional Delphi consensus study was employed to attain consensus from patients and caregivers on the QOL outcomes that should be minimally measured and reported in epilepsy clinical practice. Candidate items were compiled from QOL scales recommended by the AAN 2017 Quality Measurement Set. Inclusion criteria to participate in the Delphi study were adults with drug-resistant epilepsy diagnosed by a physician, no prior diagnosis of psychogenic nonepileptic seizures or a cognitive and/or developmental disability, or caregivers of patients meeting these criteria.

Results: A total of 109 people satisfied inclusion/exclusion criteria and took part in Delphi Round 1 (patients, n = 95, 87.2%; caregivers, n = 14, 12.8%), and 55 people from Round 1 completed Round 2 (patients, n = 43, 78.2%; caregivers, n = 12, 21.8%). One hundred three people took part in the final consensus round. Consensus was attained by patients/caregivers on a set of 36 outcomes that should minimally be included in the QOL COS. Of these, 32 of the 36 outcomes (88.8%) pertained to areas outside of seizure frequency and severity.

Significance: Using patient-centered Delphi methodology, this study defines the first COS for QOL measurement in clinical practice for adults with drug-resistant epilepsy. This set highlights the diversity of factors beyond seizure frequency and severity that impact QOL in epilepsy.

Keywords: Delphi technique; core outcome set; drug-resistant epilepsy; epilepsy; patient-centered outcomes; quality of life.

FIGURE 1

Overview of core outcome set (COS) development process. The COS development process followed four steps: (1) identifying an initial list of candidate outcomes using a systematic review, (2) filling in gaps in existing knowledge with qualitative input from focus groups comprising key stakeholders, (3) rating importance of candidate outcomes in a two-round online Delphi survey, and (4) conducting a consensus survey to ratify the final COS. AAN, American Academy of Neurology; QOL, quality of life.

FIGURE 2

Quality of life (QOL) issues ranked as critical contributors to QOL during two-round Delphi study among adults with drug-resistant epilepsy without comorbid cognitive or developmental disability. Of 248 QOL outcomes, 10 outcomes met consensus criteria for inclusion in the core outcome set (COS; red circles), and nine outcomes met consensus criteria for exclusion in the COS (dark blue circles). Items met consensus for inclusion if rated 7–9 by ≥70% and if rated 1–3 by ≤15% of respondents in both Delphi R1 and R2; items met consensus for exclusion if rated 1–3 by ≥70% and if rated 7–9 by ≤15% of respondents in both Delphi R1 and R2. Pink and gray circles are outcomes that were rated 7–9 by a majority of ≥70%. (or 1–3, respectively) but did not meet consensus criteria for being rated 1–3 by a minority of ≤15% (or 7–9, respectively). Red vertical/horizontal lines indicate 70% thresholds for inclusion in the COS, with red shading indicating items that were rated 7–9 in both Delphi rounds. Black vertical/horizontal lines indicate 15% thresholds for exclusion in the COS, with gray shading indicating items that were rated 7–9 in both Delphi rounds. Light blue circles indicate items for which a consensus was not reached during the initial Delphi study and that were voted on in the subsequent final consensus round. G, gastrostomy; GJ, gastrojejunal; IV, intravenous.

FIGURE 3

Outcomes after final consensus round and semantic similarity analysis. Following the two-round Delphi study, a final consensus round was conducted to vote on all 229 remaining no-consensus items (light blue and orange circles) from the first two Delphi rounds. The size of each circle is proportional to the percentage of respondents who voted to include each remaining item in the final core outcome set (COS). Thirty-one additional outcomes met the threshold for inclusion in the final COS from no-consensus items (orange circles). Light blue circles indicate no-consensus items that did not meet final criteria for inclusion in the COS; red circles indicate consensus items for inclusion from the first two Delphi rounds, and dark blue circles indicate consensus items for exclusion from the first two Delphi rounds. Pink and gray circles are outcomes that were rated 7–9 by a majority of ≥70% (or 1–3, respectively) but did not meet consensus criteria for being rated 1–3 by a minority of ≤15% (or 7–9, respectively). Red vertical/horizontal lines indicate 70% thresholds in Delphi R1 and R2 for inclusion in the COS. Black vertical/horizontal lines indicate 15% thresholds for exclusion in the COS. Following the final consensus round, semantic similarity analysis was employed to reduce the final COS from 41 to 36 items. The right panel lists the final COS of 36 items after semantic similarity analysis. ASM, antiseizure medication; QOL, quality of life.