How to Mitigate "Carer QALY Trap" when Including Caregiver QOL in Cost-Effectiveness Analysis: A Model Simulation Using Lecanemab in Japanese Patients with Alzheimer's Disease
Author(s)
Ataru Igarashi, PhD1, Mie K. Azuma, MSc, RPh, PhD2, Mayaka Tani, MPH2, Takuro Utsumi, BSc2, Hidetoshi Shibahara, MS3, Sachie Inoue, MBA, PhD3, Gaku Kamanaka, MSc2, Yuta Kamada, MPH4, Yukinori Sakata, RPh2, Kiyoyuki Tomita, MMA2;
1Tokyo university, Tokyo, Japan, 2Eisai Co.,Ltd, Tokyo, Japan, 3CRECON Medical Assessment, Tokyo, Japan, 4Eisai Inc., Nutley, NJ, USA
1Tokyo university, Tokyo, Japan, 2Eisai Co.,Ltd, Tokyo, Japan, 3CRECON Medical Assessment, Tokyo, Japan, 4Eisai Inc., Nutley, NJ, USA
Presentation Documents
OBJECTIVES: To address methodological issues of the “Carer QALY trap”, which arises from reflecting caregivers’ QOL as disutility in a cost-effectiveness analysis.
METHODS: A Markov model was developed to estimate disease progression over the lifetime of hypothetical Japanese patients with mild cognitive impairment or mild AD (collectively early AD) who received either lecanemab with standard of care (LEC+SOC) or SOC alone. LEC efficacy was derived from transitions between health states for 0-18 months and beyond 18 months, and the hazard ratio for time-to-worsening of Clinical Dementia Rating-Sum of Boxes (CDR-SB) estimated from the Phase III Clarity AD-36-month open-label extension was used. To reflect caregiver QOL in the model, three methods were compared: 1) no inclusion of caregiver QOL; 2) inclusion using a decrement approach, which applied disutility; and 3) inclusion using an additive approach, which using caregiver utilities using absolute values. Patient and caregiver (dis-)utilities were obtained from published literature.
RESULTS: In a cohort simulating Japanese patients with early AD (mean age 71.5 years; 52.4% female), LEC+SOC extended the mean survival time by 1.38 years (5.85vs.4.48) in patients with early AD, while shortened 0.58 years (4.44vs.5.03) in patients with moderate and severe AD. When caregiver QALYs were included by three methods above, the incremental QALYs (discounted) of LEC+SOC compared with SOC were 0.75 (6.37vs.5.61), 0.79 (6.03vs.5.24), and 1.32 (14.16vs.12.84), respectively.
CONCLUSIONS: Extending the time that patients remain in the early stages of AD should also be beneficial for caregivers. However, under the decrement approach, the longer a patient remains in the early stage of AD, the longer disutility are added to caregivers, who then accrue negative QALYs. This can lead to counterintuitive results when expressing results in terms of QALYs. The additive approach is the one that best reflects true caregiver experience and avoid the caregiver QALY trap.
METHODS: A Markov model was developed to estimate disease progression over the lifetime of hypothetical Japanese patients with mild cognitive impairment or mild AD (collectively early AD) who received either lecanemab with standard of care (LEC+SOC) or SOC alone. LEC efficacy was derived from transitions between health states for 0-18 months and beyond 18 months, and the hazard ratio for time-to-worsening of Clinical Dementia Rating-Sum of Boxes (CDR-SB) estimated from the Phase III Clarity AD-36-month open-label extension was used. To reflect caregiver QOL in the model, three methods were compared: 1) no inclusion of caregiver QOL; 2) inclusion using a decrement approach, which applied disutility; and 3) inclusion using an additive approach, which using caregiver utilities using absolute values. Patient and caregiver (dis-)utilities were obtained from published literature.
RESULTS: In a cohort simulating Japanese patients with early AD (mean age 71.5 years; 52.4% female), LEC+SOC extended the mean survival time by 1.38 years (5.85vs.4.48) in patients with early AD, while shortened 0.58 years (4.44vs.5.03) in patients with moderate and severe AD. When caregiver QALYs were included by three methods above, the incremental QALYs (discounted) of LEC+SOC compared with SOC were 0.75 (6.37vs.5.61), 0.79 (6.03vs.5.24), and 1.32 (14.16vs.12.84), respectively.
CONCLUSIONS: Extending the time that patients remain in the early stages of AD should also be beneficial for caregivers. However, under the decrement approach, the longer a patient remains in the early stage of AD, the longer disutility are added to caregivers, who then accrue negative QALYs. This can lead to counterintuitive results when expressing results in terms of QALYs. The additive approach is the one that best reflects true caregiver experience and avoid the caregiver QALY trap.
Conference/Value in Health Info
2025-05, ISPOR 2025, Montréal, Quebec, CA
Value in Health, Volume 28, Issue S1
Code
EE221
Topic
Economic Evaluation
Disease
SDC: Geriatrics, SDC: Neurological Disorders, STA: Biologics & Biosimilars