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Generic Measure of Health Status: QALY, DALY
???
????? ????? ??????
2014? 4? 3?
? ?
???? ????? QALY, DALY ? ?? ????.
1 ??
?? ???????? ???????(Sabermetrics)?? ??? ???? ??? ??? ???
? ???? ??? ???? ???, ?? ?? ??? ???????? ???? ???? ??,
??, ??? ?? ??? ?? ?? ??? ??? ??? ????? ??? ???? ?? ??
???? ? ????[1]. ?? ???? ?? ?? ??? ????? ?? ??? ????? ??
?? ???, ?? ?? ??? ???? DALY(Disability Adjusted Life Year)? QALY(Quality
Adjusted Life Year)? ??[8, 17]. ????? DALY? QALY? ??? ???? ?? ????
?? ???? ???, ?? ???? ??? ???? ??. ?? ????? ???? ???
????? ????? ??????? ? ???? ??? ? ?? ?????? ? ? ?? ??
??? ??.
2 DALY
DALY? ??? ???? ????????? ? ? ??? ?, ???? ?? ??, ??, ??
???? ?? ??? ???? ????? ??? ???. ???? ??? ??, DALY? ???
?? ???? ???. ?????????? ??? ? ????!!!? ???? ????, ???
?? ?? ???? ???? ????? ? ?? ??? ??? ???? ? ???? ?? ????
?? ????.
1

?? DALY=YLL + YLD ? ???? YLL? years of life lost? ???? ?? ??? ????.
??, ??, ??? ????? ? YLL?
YLL = N �� L (1)
(N: number of death, L: standard life expectancy at age of death in years) ????. ?? YLD?
years lost due to disability? ??? ?? ??? ???? ??? ?? ????.
YLD = I �� DW �� L (2)
(I: incidence, DW: disability weight, L: average duration of the case until remission or death(years))
?? 1: Concept of DALY
????? ??? ????? ?? ?? ?? ??? ???. ? ?? ?? ?? DALY?
??? ??? ????? ????. ??? ??? YLL, YLD ?? ???? ???? ? ???
???(Disability weight? ?????). ??, ???? ??? ???? ??? ?? ? ? ???
?? ?? ???? ???? ???? ??? ?? ??. ??? ??? ??? ?? ??? ???
?? ??? ???? ?? ???? ?????? DISMOD??.
2.1 DISMOD
DISMOD DISMOD? Global Burden of Disease 1990? ??? ??????, incidence, re-
mission, case fatality? ? ?? ??? ???? prevalence, mortality, disease duration ?? ??
2

???? ????? ?????[2]. DISMOD? ??? ?????? ???? ?? ?????
???? ????? ???? ?? ???? ?? ???? ???? ??? ? ??? ???
??.
?? 2: Conceptual Disease Model
?? 2? ??? ?? ???? ???? ??? ??.
dSa
da
= ?iaSa + raCa (3)
dCa
da
= ?(fa + ra)Ca + iaSa (4)
dDa
da
= faCa (5)
(a: age group, S: ??? ??? ?, C: ?? ????? ??? ?, D: ?? ???? ?? ???
?, i: incidence, r: remission, f: fatality)
? ?? ??? ?? ?? ??? ?? ?? ???? ??? ?? ?? incidence? ???
???? , ????? ?? ?? remission? ??? ????? ???. ? ?????? ???
3

??? i, r, f ? ?? ?? Sa, Ca, Da ? ? ? ?? ??? ???, ?? ?? prevalence? mortality
? ?? ? ??? ?? ??? ??.
PYa =
1
2
�� (Sa + Ca + Sa+1 + Ca+1) (6)
ca =
1
2
��
Ca + Ca+1
PYa
(7)
ba =
Da+1 ? Da
PYa
(8)
(PY : age interval person-year at risk, c: prevalence, b: mortality)
??? ?? ???? ?? ??? ma ? ?? ??? ??, ?????? ???? ???
ra + fa + ma ? ?? ?? ???? disease duration?? ?? ? ??. ????? incidence,
remission, case fatality? ? ?? ??? ??? ??? ???? ???? ?????? DISMOD
??.
DISMOD II DISMOD II? Global Burden of Disease 2000? ??? ??????, DISMOD
?? ???? ?????? ???? incidence, remission, fatality? ? ??? input?? ???
???? ???, ? ?? ??? ??? ????? ??? ? ?? ???[2]. ?, prevalence?
mortality ??? input?? ?? ??? ?? ??? ??? ? ??? ???. ?? ? ???
??? DISMOD? ??? ??? ??? ???? ?? ??? ?? ???? ??? ????
???? ?? ???? ???? ?? ?? 3?? ??? ??? ???? ??? ? ??. ???
????? ?? ???? ???? ? DISMOD II? ?????[18, 11, 19].
DISMOD-MR DISMOD-MR? Global Burden of Disease 2010? ??? ??????, https:
//github.com/ihmeuw/dismod_mr?? ????? ???? ?? ? ??? ???(python)??
???? ????? ???, ?? ???? ??? ????? ???? ???? DISMOD-II?
? ?? ? ???? ???? ???? ?????? ?? Meta-regression? ??? ? ???
???[16].
???? ???? ??? ???? ???? ??? ????(posterior)? ????(prior)? ??
?(likelihood)? ?? ????? ???, ?? ????? ????? ???? 0?? ???? ?
?? ??? ???? ??? ?? ???? ???? ?????, ???? ???? ?????
4

??? ??? ????? ? ? ???? ??? ? ??? ??? ??. ?? ?? ?(cancer)?
?? ????? ??? ????? incidence? ???? ??? ??? ? ??? ????
(prior)? ??? ? ???? ?? ?? ???? ?? (likelihood)? ???? ??? ?
??? ???.
? ??? ??? Meta-regression? ?? ???? ???? ??? ???? ??? ??? ?
?? ? ?? ??, ?? ??? ???? ???? ??? ??? ??? ??? ??? ? ??.
Prevalence? ?? ?? ????, ? ??? ?? ???? prevalence? ?? ?? ?? ? ???
????? ?? ????? ???? ??? ?? ??? ?? ????? ??? ??, ???,
??? ?? ? ???? ??? ? ??.
Meta-regression?? ????? ???? ??? fixed effect? random effect? ???, fixed ef-
fect? ???? ??(?: ??, ?? ?)? ????? ??? ???? ???? ???? ???
??, study-protocol ?? ???? ??? ? ???, random effect?? ???? ?? ? ???
??? ??, ???? ??? ?? heterogeniety? ??? ? ??.
???? ??? ?????? ?? ??? ???? ??? ?? NECA ??????? 3.
???? ?????? ???? ???.
2.2 Adjustment
DALY??? ??? ???? ??? ?? ??? ???. YLL=N��L, YLD=I��DW��L ? ??
??? ???? ?? ???, ???? ????? ????? ???? ??? ??? ??.
?????(weighting) ?? ??? ??? ?? ??? ???? ? ???? ??.
???(discounting) ??? ????? ??? ?????? ? ???? ??(?: 3%)
??????
?????? ??? ????? 0, ??? 1? ???? ??? ??? ?? PTO(person trade-
off), VAS ?? ??? ???? ??? ???? ??
?? ?? 3%? ???? ????? YLL? YLD? ?? ??? ?? ??? ??.[6].
5

YLL =
N
0.03
(1 ? e?0.03L
) (9)
YLD =
I �� DW
0.03
(1 ? e?0.03L
) (10)
??? ??????? ???? ?? ? ????? ?? ?? ??? ????? ????
???.
2.3 Disability weight
????? ??? ?? ???? ? ???. ??? ??? ????? ????? Ranking,
Visual Analog Scale(VAS), Standard Gamble(SG), Time Trade-Off(TTO) ?? ??
? ???? ??? ??? ????? ???[10, 7, 4, 3]. GBD(Global burden of disease) 1996
??? ????? ?????? ��person trade-off��?? ??? ??????[9], ?? 3? ??
??? ? ???.
?? 3: Person trade-off
?????? ???? ??? ??????, ????? ??? 22?? indicator condition?
?????? ?? 7??? ?? ??? ?? ?, ??? ??? ???? ?? ?? ??? ???
??? ?? ??? ??(?? 4).
6

?? 4: Person trade-off(2)
GBD 2010 GBD 2010??? 289?? ??? 1160?? sequelae? ??? 220?? health status
? ?? ???? ? ? ?? ????(?? 5)[16], ?????? population-based household
survey? open-access internet survey? ?????? ?? paired comparison? population
health equivalence??? ??. ? ? population health equivalence? ?? ??? person trade-
off ??? ????, paired comparison? ??????? ??, ??????? ??? ????
?????? paired comparison? ??? ????? ??? ? ? ???, population health
equivalence?? ?? ????? ??? ?? ??? ? ? ?? ????? 0-1??? ???
??? ? ?? ???[13]. ?? ???? paired comparison? ??? 0-1? scale? ??? ?
??.
1. paired comparison : ???? ??? ???!!
2. health equivalence: ? ??? ??? ?? ??????? ???. (0-1)??
3. ???? ??? ?? ?? ??? 0-1??? ??.
3 QALY
QALY(Quaility Adjusted Life Year)? ?? ?? ????? ???? ??? 1976?? ?? ?
?? ???? ???? ?? ??? ? ?? ?? ?? ????, disease burden? ???? ??
7

?? 5: Disability weight in GBD 2010
???? DALY? ??? ??? ??? ??[20]. ?? ????? ???? ??? ????
QALY? DALY? ???? ?? ??? ? ??? ?? DALY??? ??? ??? 0, ??? 1?
??? QALY??? ??? ??? 1? ?? ?? ?? ?? ??? 0-1??? ???? ???
????. ?? ??? 1? ?? ?? ??? ??? 1? ?? ???? ???? ?? ??? ???
???? ??? ??? ???? ? ?? ??? ?? age weighting? ??????? ???
??. ?? ??? ?? 6? ???? ???, ?? ? ????? QALY? ???? ?? ???
???? ????? ???.
3.1 Calculation of QALY
QALY ??? ?? ??? [14]? ??? ????? ??? ??? ??? ???.
?? ??? Quality Q(0-1)? ??? 1?? ??? ??. ??? ? 1???? QALY?
QALYs lived in one year = 1 �� Q (11)
8

?? 6: Concept of QALY
? ??, ??? ?? ??? a ???? ??? ????(QALE: Quality Adjusted Life Ex-
pectancy)? ??? ??.
QALE =
a+L
a
Qt (12)
(L: residual life expectancy of the individual at age a, t: time unit)
??? DALY ??? discounting? ????? ?, ??? ?? ?? ? ???? ???
Discounted QALE =
a+L
a
Qt
(1 + r)t?a
(13)
(r: discounting rate)
? ??. ?, ???? ??? ? ?? ??? QALY? ??? ? ?? ???. ?? ???
QALY? ?? ??? ???? ? ??? ??? QALY? ? ??? cost-effectiveness??? ??
9

???. ?? ?? intervention i? ??? ?? quality??? Qi ? ?? ???(no intervention
or standard intervention) quality ??? Q? ?? QALY? ???
QALYs gained =
a+Li
a
Qi
t
(1 + r)t?a
?
a+L
a
Qt
(1 + r)t?a
(14)
(Li: residual life expectancy after intervention i)
? ??? ? ??.
3.2 DALY?? ???
Quality scale? disability scale? ????? ??? ??? ??????, ?? ??? DALY
?? ???? ??. ?????? DALY? weight? ????? ????? ???, QALY?
weight? ?? ?????? ????? ????? ???(GBD 2010? ??). ????? ??
?? ???? GBD 2010??? ??? ???? ???, ????? ???? ???? Health
Utilities Index (Torrance et al. 1996) ? EuroQol (Dolan 1997)? ??? ????? EuroQol?
EQ-5D(EuroQOL five dimensions questionnaire)? 3 level ??? ????? ???[15, 5, 12].
EQ-5D-3L? ?? ??? 5?? ???? 3?? ??? ?? ?? ?????? ??? Demension
? Mobility, Pain/discomfort, Self-care, Anxiety/depression, Usual activities? 5?
?? ?? ? ???? ?? ?? ?? ???? 123?? level? ????(?? 7). ??? ???
???? ??? TTO? VAS ???? ?? ??? ???? weighting? ???? ??? ??
???? TTO, VAS? EQ-5D? ????? ?? ??? reference? ??? ?? ???? ??.
??? ??? http://www.economicsnetwork.ac.uk/health/EQ_5D_index_calculator.xls
? ???? ??.
3.3 ??? QALY
QALY? DALY?? ???? ? ??? ??? ?? ?? age weighting??. ?? ??? QALY
? ???? age weight? ?? ??? ???, ?? ??? ??? ?????? ?? ?? ???
??? ???? ???? ????. ?? discount? ???? ??? ?????? discrete??
???? ?? ????? ???? ?? DALY? ?? ???? ????. ??? ??? ??.
?? discounting? ????? ????? QALE? ??? ??. ??? ?? QALE? ???
??.
10

?? 7: Concept EQ-5D-3L
QALE =
a+L
a
Qe?r(x?a)
dx = Q
1 ? erL
r
(15)
(r: discounting rate, L: residual life expectancy of the individual at age a)
?? ?? intervention i? ?? QALEs gained?
QALYs gained = Qi 1 ? erLi
r
? Q
1 ? erL
r
(16)
(i: intervention i)
? ??. ?? age-weighting? ???. a?? a + L???? ??? ??? ??? ????
??? ? ???? Q?? ??? ???? ???. ??? ??? ????? ???? ???.
4 ???..
???? ????? ????? DALY? QALY? ??? ??? ??? ?????. ?? ??
?? ? ??? ??? ??? ???? ?? ??? ???? ??? ? ???, ???? ????
11

???? ?? ??? ?? ??? ????? ??? ??, ???? ??? ???? ?? ???
??? ??? ???? ???? ??? ???. ??? ?? ?????? ??? ??? ??
? ?? DISMOD-MR?? ?? ????? ?? DISMOD III? ????? ??? ?????
??? ??? ???? ???? ??? MCMC? ??? ?? ???? ?? ???? ??
?????? ???? ? ?? ????? ?? ???? ??????? ????? ?? ??
???? ???? ??.
DALY? QALY? ?? ??? ???? ???? ?? ????? ??? ?? ?? ?? ???
???? ?? ?????? ?? ?? ?? ????? ????? ????? ??? ???
??? ?????? ??? ????, Burden of disease? ?? ???? ???? ??? ???
XXX??? YYY??? Burden of disease..? ?? ????? ?? ?? ?? ?? ???? ??
?? DISMOD MR? ? ??? ?? ??? ?????? ??? ??? ???? ??? ???.
?????? Disability-adjusted? Quality-adjusted? ?? Desire-adjusted life year?? ???
???? ?? ??? ??. ?? ??? ????? ??? ??, ??? ????? ?? ???
??? ??? ??.
?? ??
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12

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