FRI0563 COMPARISON OF TWO DIFFERENT APPROACHES TO INVOLVE PARTICIPANTS IN CONSECUTIVE ROUNDS OF A DELPHI CONSENSUS TECHNIQUE.
Authors: A. Boel, V. Navarro-Compán, R. B. M. Landewé, D. Van der Heijde
Journal: Annals of the Rheumatic Diseases (2020)

Background: There is no guidance on which participants to invite to consecutive rounds of a Delphi exercise. There are two options: 1) Invite only participants that have completed the previous round for the consecutive round; 2) Invite every participant for all consecutive rounds irrespective of whether they have responded. It is unknown whether different invitation-procedures provide similar results. Objectives: To investigate the effect of two different approaches to involve participants in consecutive rounds of a Delphi exercise on response rate and final outcome. Methods: Patients with and experts in spondyloarthritis were invited to partake in a 3-round Delphi exercise to update a core outcome set. A randomised controlled study with 1:1 allocation to two experimental groups was built in, to compare two approaches of invitation. The ‘all-rounds group’ includes patients invited for each round independent of response to the previous round; the ‘respondents group’ includes patients invited for the next round only if they responded to the previous round. A 9-point Likert scale (1=not important; 9=critical) was used to score the importance of domains. Additionally, participants provided their six most important domains. Results: The overall response rate after 3 rounds was lower in the ‘respondents’ compared to the ‘all-rounds group’ (46% vs. 61%) (table 1). Table 1. Response rates per group per round of the Delphi exercise ‘Respondents group’ (N=187) ‘All-rounds group’ (N=189) Round 1 Invited: 187 Completed: 122 Response rate: 65% Invited: 189 Completed: 110 Response rate: 58% Round 2 Invited: 122 Completed: 95 [response rate (78%)] Overall response rate: 51% Invited: 189 Completed: 105 Response rate: 56% Round 3 Invited: 95 Completed: 86 [response rate (91%)] Overall response rate: 46% Invited: 189 Completed: 116 Response rate: 61% There was no difference in mean (standard deviation) scores between the ‘respondents’ and ‘all-rounds’ groups for any domain (figure 1). After the final round, the 4 outcomes with the highest percentage of votes were identical between experimental groups, with only small differences in percentages between groups (table 2). The only difference in the 6 most important domains was selection of disease activity by the ‘respondents group’, whereas the ‘all-rounds group’ selected overall functioning &amp; health, while these domains were ranked as the 7 th domain in the other group. Table 2. Most important domains after round 3 for the ‘respondents’ and ‘all-rounds’ groups ranked in descending order, based on selection by the ‘respondents’ and matched in the ‘all-rounds group’; and the difference in percentage of votes between groups. Domains in italic and bold represent the top 6 in each experimental group. ‘Respondents group’ N=86 ‘All-rounds group’ N=116 Difference between groups Pain 95% Pain 91% Pain 4% Stiffness 62% Stiffness 62% Stiffness 0% Physical functioning 62% Physical functioning 61% Physical functioning 1% Mobility 59% Mobility 54% Mobility 5% Disease activity 55% Disease activity 49% Disease activity 6% Fatigue 50% Fatigue 55% Fatigue -5% Overall functioning &amp; health 47% Overall functioning &amp; health 57% Overall functioning &amp; health -10% Extra-musculoskeletal manifestations 44% Extra-musculoskeletal manifestations 45% Extra-musculoskeletal manifestations -1% Peripheral manifestations 34% Peripheral manifestations 44% Peripheral manifestations -10% Sleep 30% Sleep 26% Sleep 4% Work &amp; Employment 21% Work &amp; Employment 23% Work &amp; Employment -2% Emotional functioning 16% Emotional functioning 18% Emotional functioning -2% Conclusion: Inviting persons for all rounds irrespective of a response to the previous round increases the generalisability, while the content of the outcome of a Delphi procedure is similar to using data of those persons who participate in all rounds only. Disclosure of Interests: Anne Boel: None declared, Victoria Navarro-Compán Consultant of: Abbvie, Lilly, Novartis, Pfizer, UCB, Speakers bureau: AbbVie, MSD, Lilly, Novartis, Pfizer, UCB, Robert B.M. Landewé Consultant of: AbbVie; AstraZeneca; Bristol-Myers Squibb; Eli Lilly &amp; Co.; Galapagos NV; Novartis; Pfizer; UCB Pharma, Désirée van der Heijde Consultant of: AbbVie, Amgen, Astellas, AstraZeneca, BMS, Boehringer Ingelheim, Celgene, Cyxone, Daiichi, Eisai, Eli-Lilly, Galapagos, Gilead Sciences, Inc., Glaxo-Smith-Kline, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sanofi, Takeda, UCB Pharma; Director of Imaging Rheumatology BV