OBJECTIVES:

Appraisals of Highly Specialised Technologies (HST) for rare conditions by the National Institute for Health and Care Excellence (NICE) often require expert opinion to inform model data gaps. NICE HSTs were reviewed to identify model parameters informed by expert opinion, to understand when it may be appropriate, and if any specific methods are preferred.

METHODS:

NICE HST guidelines and supporting material published before January 2022 were reviewed. The technology, indication, parameters, elicitation methodology, concordance with NICE methods and process guides, the views of the Evidence Review Group (ERG) and NICE Committee, and final recommendations, were systematically extracted and summarised.

RESULTS:

Sixteen HST appraisals were reviewed, with 14 (88%) using expert opinion to inform model parameters. In these submissions, nine (64%) conducted interviews, five (36%) a Delphi consensus panel, two (14%) a survey, and two (14%) a workshop or advisory board. The number of interviewed experts ranged from 1–7, the average number of Delphi panel participants was 4.6 and survey participants was 8.5. The most frequent parameters informed by expert opinion were resource use and utility values, but also included efficacy and natural history parameters. Parameter uncertainty was evaluated with credible intervals informed from either the pooled responses or an arbitrary range. The NICE Committee generally accepted parameters derived from expert opinion if the ERG did not prefer an alternative source of evidence, and if clinical experts agreed with the parameter’s value.

CONCLUSIONS:

NICE HST appraisals often require expert opinion to inform models due to limited evidence available for rare conditions. Several methods have been used by companies to date, and NICE generally accepts these when more robust evidence is not available, and when the elicitation methods are clearly reported.