What is the NICE severity modifier?
Author: Ben Barron-Millar, Senior Consultant
In 2022, National Institute for Health and Care Excellence (NICE) introduced the severity modifier to give greater importance to treatments for more serious health conditions as an alternative to end-of-life (EoL) criteria. In non-EoL conditions (such as cystic fibrosis and chronic hepatitis), the extra weight given to health gains has increased the likelihood of a positive treatment recommendation for reimbursement.
Overall, out of 32 appraisals submitted using the severity modifier, NICE have issued 27 positive recommendations. The proportion of positive decisions involving the additional severity weighting (84.4%) is higher than if end-of-life modifier was used (82.7%).
For a disease to qualify for the severity modifier, patients must be expected to lose substantial amounts of their future health (see Table 1 below). NICE, however, has provided little explanation of how the eligibility cutoffs and weights were determined, or how they may be aligned with societal preferences.
| No Multiplier | 1.2 Value Multiplier | 1.7 Value Multiplier | |
|---|---|---|---|
| Absolute Shortfall (AS) | <12 Discounted QALYs | 12-18 Discounted QALYs | ≥18 Discounted QALYs |
| Proportional shortfall (PS) | <85% PS | 85% – 95% PS | ≥95% PS |
Table 1: Overview of NICE severity modifier criteria
Example of severity modifier with absolute shortfall (AS) and proportional shortfall (PS). Abbreviations: AS , absolute shortfall; NICE, National Institute for Health and Care Excellence; PS, proportional shortfall; QALYs; quality-adjusted life years. Source: OHE (2024).
Last September, NICE reviewed the impact of the severity modifier to date and deemed that it is “working as intended.” They noted that it has led to a broader range of treatments being recommended, including for conditions like cystic fibrosis and non-EoL cancers which previously would not have qualified under the previous criteria. NICE has not announced any further public consultations specifically on the severity modifier.
In an Association of the British Pharmaceutical Industry (ABPI)-sponsored study, the Office for Health Economics (OHE) surveyed a representative sample of the population of England and Wales to understand how the public would prioritise health gains for more severe diseases.
This quantitative preference study used a Person Trade-Off (PTO)-based approach to understand the value of health gains to patients with a greater vs lesser future health. In turn this allow determination of how well the criteria of the NICE severity modifier aligns with UK societal preferences.
The primary objectives of this study were to estimate:
- Cut-offs for ‘severe’ and ‘very severe’ categories by absolute shortfall (AS) and proportional shortfall (PS).
- The relative value of health gains across the range of possible shortfall scores, in comparison to a low-severity (20% PS) group.
NICE severity modifier doesn’t align with public values
The analysis (as per Figure 1) of this study’s sample population (n=990) revealed the following:
- The public assigns greater value to health gains at almost every level of severity, compared with NICE’s current severity modifier.
- Analysis showed that the public viewed ‘severe’ health states started at ~50% PS (vs NICE PS of 85%)
- Additionally, the public’s perceived threshold for ‘very severe’ conditions begins and plateaus at a 65% proportional shortfall (vs NICE PS of 95%).
Figure 1: Public sample reported proportional shortfall vs reference NICE severity thresholds
Analysis showing the median relative values across different proportional shortfall severity levels, compared to NICE’s current severity categories and value multipliers. Abbreviations: NICE, National Institute for Health and Care Excellence; PS shortfall. Source: OHE (2024).
Key findings from OHE study
These findings suggest that the public supports a more inclusive and equity-focused approach to prioritising health interventions.
- Members of the public are willing to prioritise patients with lower levels of health shortfall than NICE’s thresholds suggest.
- PS shortfall value plateau at ~65% indicates a critical threshold in public perception of health.
Conclusion:
This study finds that NICE’s current severity modifier does not appear to be well aligned with the public’s preference for prioritising health gains for more severe diseases in England and Wales.
If NICE aims to reflect societal values in its decision-making, this study provides compelling evidence for revisiting the criteria of the current severity modifier framework.
For further information, please consult the full report published by the OHE (see link below).
Sources:
- NICE Severity modifier (2025): What is NICE’s severity modifier? URL: https://indepth.nice.org.uk/what-is-nices-severity-modifier/index.html
- NICE News Article (September 2024): NICE Board says new method allowing greater weight to be given to severe diseases is working URL: https://www.nice.org.uk/news/articles/nice-board-says-new-method-allowing-greater-weight-to-be-given-to-severe-diseases-is-working.
- Hayes H, Radu P, Mott D, Skedgel C, 2024. Understanding societal preferences for priority by disease severity in England & Wales. OHE Contract Research Report, London: Office of Health Economics. URL: https://www.ohe.org/publications/understanding-societal-preferences-for-priority-bydisease-severity-in-england-wales/
Acronyms:
- OHE: Office of Health Economics
- NICE: National Institute for Health and Care Excellence – body responsible for appraising health technology assessments for new medicines in England/Wales.
- Absolute shortfall: used to measure total degree of health lost to a condition.
- Proportional shortfall: used to measure the fraction of remaining health lost.
- QALY: quality-adjusted life-year – total number of years of life a person is expected to live (i.e. 1 QALY = 1 year of life in perfect health).
- PTO: person trade-off – method used to determine and prioritise social value of health care interventions.
