Will NICE’S New Severity Weighting Criteria Be Capable of Identifying Severe Conditions?

BACKGROUND: NICE’s revised technology appraisal methods include the introduction of QALY severity weights of 1.2 and 1.7, leading to potential upper cost-effectiveness thresholds of £36,000 and £51,000, respectively. The weighting is calculated by assessing the absolute and proportional shortfall in discounted QALYs between people with the condition and the general population. The use of discounted QALYs in the severity calculation contrasts with the previous criteria for end of life QALY weighting, which were based on undiscounted life years, and the weighting applied in the Highly Specialised Technology (HST) process, which is determined by undiscounted QALY gains.

OBJECTIVES: To test the performance of the new NICE severity weight criteria on published HSTs, which can only be appraised via this route if the condition is considered “chronic and severely disabling”.

METHODS: The following data were extracted from HSTs published on the NICE website: the Evidence Review Group’s preferred QALYs for the comparator arm, discount rate used, whether the QALYs included carer disutility, age and proportion female at model entry, time horizon, and whether a QALY weighting was allocated by the appraisal committee. Data from each HST were input into the online R Shiny QALY shortfall calculator and the severity weight was recorded.

RESULTS: 20 HSTs were analysed, of which 14 had sufficient data to calculate a severity weight. Of these, 7 (50%), 2 (14%) and 5 (36%) achieved a severity weight of 1.7, 1.2 and 1, respectively. Of the 8 HSTs that were allocated a QALY weight by the NICE HST committee, 2 (25%) only achieved a severity weight of 1.

CONCLUSIONS: One third of conditions previously considered severe by NICE may not be allocated a QALY weighting using the new severity weighting criteria. This includes conditions previously allocated weights due to shortfalls of >10 undiscounted QALYs under HST weighting criteria.