「プロジェクト評価論」第11回 2005/12/13 担当：駒井 正晶
より
gc.sfc.keio.ac.jp/class/2005_14725/slides/11/25.html
QALY(Quality-Adjusted Life-Years：質を調整した生存年数)
＊QALYの評価値（＝効用）の推定
1.評点尺度法：完全に健康(1.0)と死亡(0)の間に様々な健康状態がどのあたりに位置するかを調査
2.スタンダード・ギャンブル法：リスクの異なる状態の一対評価を行う
3.時間トレードオフ法：効用値と期待生存年数の積が２つの代替案で等しくなる場合を求める
＊内科的治療では狭心症で家から出られない状態でa年生きられるとする
＊冠動脈バイパス手術によりほぼ通常の生活ができるなら、あと何年しか生きられなくてもよいか（ｂ年）を質問
a×U＝ｂ×1.0
＊A＝10、b=8なら、U（狭心症の効用値）は0.8
・ボードマン他(2004)Ch.17.
・武藤孝司『保健医療プログラムの経済的評価法』篠原出版新社、1998.
・Eric Nord, Cost-Value Analysis in Health Care: Making Sense out of QALYs,
Cambridge University Press, 1999.
What is a QALY?
www.evidence-based-medicine.co.uk/ebmfiles/WhatisaQALY.pdf
● A quality-adjusted life-year (QALY) takes into account
both quantity and the quality of life generated by healthcare
interventions. It is the arithmetic product of life expectancy
and a measure of the quality of the remaining life-years.
● A QALY places a weight on time in different health states. A year
of perfect health is worth 1; however, a year of less than perfect
health life expectancy is worth less than 1. Death is considered
to be equivalent to 0, however, some health states may be
considered worse than death and have negative scores.
● QALYs provide a common currency to assess the extent of the
benefits gained from a variety of interventions in terms of
health-related quality of life and survival for the patient. When
combined with the costs of providing the interventions,
cost–utility ratios result; these indicate the additional costs
required to generate a year of perfect health (one QALY).
Comparisons can be made between interventions, and
priorities can be established based on those interventions that
are relatively inexpensive (low cost per QALY) and those that
are relatively expensive (high cost per QALY).
● QALYs are far from perfect as a measure of outcome, with
a number of technical and methodological shortcomings.
Nevertheless, the use of QALYs in resource allocation
decisions does mean that choices between patient groups
competing for medical care are made explicit and
commissioners are given an insight into the likely benefits
from investing in new technologies and therapies.
To access the full text version of this publication
and the other titles in this series go to:
www.whatisseries.co.uk
■ What is evidence-based medicine?
■ What is an NNT?
■ What is cost-effectiveness?
■ What are health utilities?
■ What is a systematic review?
■ What is a QALY?
■ Implementing NNTs
■ What is meta-analysis?
■ What is quality of life?
■ What is a Cox model?
■ What makes a good clinical guideline?
■ What is clinical governance?
■ Implementing QALYs
■ What is critical appraisal?
■ What is an integrated care pathway?
■ What are confidence intervals?
■ What is NICE?
■ What is clinical audit?
■ What is PBMA?
■ Implementing PBMA
■ What is health economics?
© Hayward Medical Communications, a division of Hayward Group plc
