Does Modeling Adherence Matter? Insights From Prior NICE Appraisals
Author(s)
Thomas P. Kloska, MSci1, Jessica Amis, MSc2, Naomi van Hest, MSc3.
1Costello Medical, London, United Kingdom, 2Costello Medical, Manchester, United Kingdom, 3Costello Medical, Bristol, United Kingdom.
1Costello Medical, London, United Kingdom, 2Costello Medical, Manchester, United Kingdom, 3Costello Medical, Bristol, United Kingdom.
OBJECTIVES: Without treatment adherence, likelihood of clinical benefit diminishes significantly. Adherence can substantially influence treatment outcomes and thus has important implications for cost-effectiveness. A review of health technology assessment (HTA) appraisals was conducted to examine approaches to modelling adherence, and criticism by assessors.
METHODS: NICE appraisals with published final guidance between May 2024 and May 2025 were reviewed. Information on treatment adherence modelling methods and critique from External Assessment Groups and Committees was extracted.
RESULTS: Of 72 appraisals reviewed, only 34 reported adherence data in clinical sections. Twenty nine appraisals reported modelling reduced adherence for the intervention or comparator; 34 appraisals reported no adherence modelling information, of which four received assessor criticism; on three occasions, manufacturers argued higher intervention compliance rates justified modelling full adherence as a conservative assumption. Nine appraisals reported an assumption of 100% adherence across treatments. Adherence was only modelled using dose adjustment, exclusively impacting drug costs. Assessors criticised adherence modelling in over half of appraisals (n=6) where adherence was reported as a key driver of results (n=9). Criticisms included inconsistent application of adherence across treatments (n=3), preference for an alternative source of adherence (n=2), or concern about using dose intensity versus dose skipping data (n=1). Preferences for alternative adherence sources or assumptions (n=5), inconsistent application of adherence between treatments (n=2) or concerns over using dose intensity versus dose skipping (n=2) were raised by Committees.
CONCLUSIONS: Adherence is an underreported outcome in HTA dossiers and economic modelling. When modelled, it is often only through cost impact. Given drug costs are frequently the main contributor to results, it can be a key driver and subject to criticism. Therefore, care should be taken when modelling adherence impact on cost, ensuring the most appropriate source and definition of adherence is used for all treatments within the model, considering the efficacy source being utilised.
METHODS: NICE appraisals with published final guidance between May 2024 and May 2025 were reviewed. Information on treatment adherence modelling methods and critique from External Assessment Groups and Committees was extracted.
RESULTS: Of 72 appraisals reviewed, only 34 reported adherence data in clinical sections. Twenty nine appraisals reported modelling reduced adherence for the intervention or comparator; 34 appraisals reported no adherence modelling information, of which four received assessor criticism; on three occasions, manufacturers argued higher intervention compliance rates justified modelling full adherence as a conservative assumption. Nine appraisals reported an assumption of 100% adherence across treatments. Adherence was only modelled using dose adjustment, exclusively impacting drug costs. Assessors criticised adherence modelling in over half of appraisals (n=6) where adherence was reported as a key driver of results (n=9). Criticisms included inconsistent application of adherence across treatments (n=3), preference for an alternative source of adherence (n=2), or concern about using dose intensity versus dose skipping data (n=1). Preferences for alternative adherence sources or assumptions (n=5), inconsistent application of adherence between treatments (n=2) or concerns over using dose intensity versus dose skipping (n=2) were raised by Committees.
CONCLUSIONS: Adherence is an underreported outcome in HTA dossiers and economic modelling. When modelled, it is often only through cost impact. Given drug costs are frequently the main contributor to results, it can be a key driver and subject to criticism. Therefore, care should be taken when modelling adherence impact on cost, ensuring the most appropriate source and definition of adherence is used for all treatments within the model, considering the efficacy source being utilised.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
EE342
Topic
Economic Evaluation, Health Technology Assessment
Disease
No Additional Disease & Conditions/Specialized Treatment Areas