RESEARCH Open Access
Valida ion o a compu e -adap i e es o
e alua e gene ic heal h- ela ed quali y o li e
Pablo Rebollo
1*
, Ignacio Cas ejón
1
, Jesús Cue o
1
, Guille mo Villa
1
, Edua do Ga cía-Cue o
2
, Helena Díaz-Cue o
1
,
Pila C Za daín
1
, José Muñiz
2
, Jo di Alonso
3,4
, he Spanish CAT-Heal h Resea ch G oup
Abs ac
Backg ound: Heal h Rela ed Quali y o Li e (HRQoL) is a ele an a iable in he e alua ion o heal h ou comes.
Ques ionnai es based on Classical Tes Theo y ypically equi e a la ge numbe o i ems o e alua e HRQoL.
Compu e Adap i e Tes ing (CAT) can be used o educe es s leng h while main aining and, in some cases,
imp o ing accu acy. This s udy aimed a alida ing a CAT based on I em Response Theo y (IRT) o e alua ion o
gene ic HRQoL: he CAT-Heal h ins umen .
Me hods: C oss-sec ional s udy o subjec s aged o e 18 a ending P ima y Ca e Cen es o any eason. CAT-
Heal h was adminis e ed along wi h he SF-12 Heal h Su ey. Age, gende and a checklis o ch onic condi ions
we e also collec ed. CAT-Heal h was e alua ed conside ing: 1) easibili y: comple ion ime and es leng h; 2)
con en ange co e age, I em Exposu e Ra e (IER) and es p ecision; and 3) cons uc alidi y: di e ences in he
CAT-Heal h sco es acco ding o clinical a iables and co ela ions be ween bo h ques ionnai es.
Resul s: 396 subjec s answe ed CAT-Heal h and SF-12, 67.2% emales, mean age (SD) 48.6 (17.7) yea s. 36.9% did
no epo any ch onic condi ion. Median comple ion ime o CAT-Heal h was 81 seconds (IQ ange = 59-118) and
i inc eased wi h age (p < 0.001). The median numbe o i ems adminis e ed was 8 (IQ ange = 6-10). Nei he
ceiling no loo e ec s we e ound o he sco e. None o he i ems in he pool had an IER o 100% and i was
o e 5% o 27.1% o he i ems. Tes In o ma ion Func ion (TIF) peaked be ween le els -1 and 0 o HRQoL.
S a is ically signi ican di e ences we e obse ed in he CAT-Heal h sco es acco ding o he numbe and ype o
condi ions.
Conclusions: Al hough domain-speci ic CATs exis o a ious a eas o HRQoL, CAT-Heal h is one o he i s IRT-
based CATs designed o e alua e gene ic HRQoL and i has p o en easible, alid and e icien , when adminis e ed
o a b oad sample o indi iduals a ending p ima y ca e se ings.
Backg ound
Heal h-Rela ed Quali y o Li e (HRQoL) is among he
mos used a iables in Heal h Ou comes Resea ch
(HOR) in he academic ield, as well as in clinical ials
and pos -au ho isa ion s udies. I e e s o he subjec i e
alua ion o he in luence o heal h on he indi iduals’
abili y o ha ing a no mal unc ioning which makes i
possible o pe o m all he ac i i ies which a e impo an
o hem and which a ec hei well-being [1]. Al hough
du ing he las 35 yea s HRQoL assessmen has had an
eno mous de elopmen wo ldwide, se e al ba ie s limi
i s use in he clinical p ac ice. These ba ie s had been
desc ibed by Deyo and Pa ick in 1989 [2] and we e
e ised in Spain in 2005 [3]. Classical Tes Theo y
(CTT) canno sol e ce ain p ac ical issues, such as he
high numbe o ques ions needed o comple e a mul i-
dimensional HRQoL ques ionnai e and he lack o accu-
acy when dealing wi h he change o indi idual sco es
o e ime. I em Response Theo y (IRT) [4,5] o e comes
some o he limi a ions ha may a ec ins umen s
de eloped unde he CTT. CAT ins umen s based on
IRT, clea ly inc ease “measu emen e iciency”( he a io
o a measu e’s psychome ic soundness o he esponse
bu den he measu es imposes). A g ea e measu emen
p ecision can be achie ed h ough he selec ion o a ew
i ems om a calib a ed i em pool ha combines high
* Co espondence: [email p o ec ed]
1
BAP Heal h Ou comes Resea ch, Calle Azcá aga 12 A, 33010, O iedo, Spain
Full lis o au ho in o ma ion is a ailable a he end o he a icle
Rebollo e al.Heal h and Quali y o Li e Ou comes 2010, 8:147
h p://www.hqlo.com/con en /8/1/147
© 2010 Rebollo e al; licensee BioMed Cen al L d. This is an Open Access a icle dis ibu ed unde he e ms o he C ea i e Commons
A ibu ion License (h p://c ea i ecommons.o g/licenses/by/2.0), which pe mi s un es ic ed use, dis ibu ion, and ep oduc ion in
any medium, p o ided he o iginal wo k is p ope ly ci ed.
quali y i ems om mul iple ins umen s in o a single
da a esou ce [6]. Since each i em is independen ly
desc ibed by pa ame e s such as di icul y o disc imina-
ion [7], hey can be combined as necessa y, he e o e,
he e is no ques ionnai e as such bu di e en combina-
ions o i ems which p o ide compa able sco es.
Th ough IRT, an I em Cha ac e is ic Cu e (ICC) is
cons uc ed o each i em; his cu e e lec s he p ob-
abili y o he answe o each i em o each HRQoL le el.
Using ICC, he HRQoL le el o a gi en subjec can be
es ima ed a e answe ing any numbe o i ems. Fu he -
mo e, IRT allows us o es ima e he con ibu ion each
i em makes o he assessmen o each le el o he a i-
able: he In o ma ion Func ion. Measu emen e o is
in e sely linked o he in o ma ion used and hence an
e o es ima e is a ailable o each assessmen .
Based on his heo y, Compu e Adap i e Tes s
(CATs) a ise as a psychome ic assessmen echnique
adminis e ed h ough a compu e . Fo each esponden ,
he selec ion o i ems is adap ed o he p io es ima es
o he cons uc being assessed [7]. These es s ha e
been success ully used in Educa ion and Psychology
ields [8] and hey allow a mo e p ac ical assessmen
and a mo e accu a e es ima ion o he a iable being
measu ed, in his case, HRQoL. CATs esul in he indi-
idual adminis a ion o ques ionnai es, as well as in he
collec ion and compu a ion o esponses, p o iding
ins an esul s [9].
Since he 90 s, when some au ho s ecommended
CAT applica ions o heal h [10], a a ie y o CATs
ha e been de eloped in he Heal h ield, as hose o
mig aine [11,12], heuma oid a h i is [13], os eoa h i is
[14], back pain [15], physical he apy [16,17], anxie y
[18], cance [19] and paedia ics [20]. All hese CATs
ocus on one speci ic condi ion o HRQoL domain, bu
hey canno measu e gene ic HRQoL in heal hy o ill
subjec s om he gene al popula ion. As i is well
known, HRQoL is essen ially a mul idimensional con-
cep . This ac could make i di icul o accomplish he
unidimensionali y equi ed o he applica ion o IRT
[21]. Despi e his ac , we hink i is possible o de elop
a calib a ed i em pool o measu e he unde lying con-
s uc o gene ic HRQoL. Pu suing his aim, in a p e-
ious s udy [22], an expe panel p oposed a pool o 140
i e-le el Like i ems, chosen among se e al HRQoL
ques ionnai es alida ed in Spain. Tha pool was i s
adminis e ed o a pilo sample and la e o a gene al
sample o pa ien s belonging o 7 P ima y Heal h cen-
es. Two adminis a ion op ions we e o e ed o he
la e sample: 1) on pape 2) on a ouch panel. I em
Response Theo y psychome ic p ope ies (disc imina-
ion, eliabili y and alidi y) we e e alua ed by means o
a Fac o ial Analysis and o he me hods. The In o ma-
ion Func ion was analyzed and an applica ion me hod
was es ed by means o simula ion: a minimum o
5 i ems and a maximum o 15 we e shown; he i s
i em was andomly selec ed among 13 which deal wi h
gene ic heal h aspec s and co e ed a b oad HRQoL
ange. These 13 ini ial i ems we e selec ed among he
mos in o ma i e i ems by an expe panel. The esul
was a calib a ed pool o 96 i ems [22]. This pool o i ems
showed a ac o ial s uc u e in one dimension (wi h 45%
o he a iance explained and a lowes loading o 0,224)
and e idenced high eliabili y (C onbach’s al a = 0.99).
This manusc ip p esen s he alida ion o CAT-
Heal h: a CAT based on he desc ibed calib a ed i em
pool, using he men ioned applica ion me hod and
implemen ed wi h a ouch sc een in e ace. This alida-
ion s udy, ga he ing in o ma ion om a sample o sub-
jec s om he Spanish gene al popula ion, pu sues he
goal o ob aining a easible and accu a e ins umen o
measu e gene ic HRQoL in he clinical se ing.
Me hods
A c oss-sec ional s udy o subjec s aged o e 18 a end-
ing one o he ou pa icipan P ima y Ca e Cen es
(PCC) o any eason was ca ied ou , in o de o assess
he alidi y o CAT-Heal h. The s udy hence included
subjec s wi h ch onic condi ions o acu e pa hologies
bu also heal hy subjec s, o ins ance, pa ien s’heal hy
ela i es a he PCC. Be o e hei inclusion, all pa ien s
we e in o med and p o ided w i en in o med consen ,
in acco dance wi h he e hical p inciples o he Decla a-
ion o Helsinki and he Good Clinical P ac ice
guidelines.
Da a we e collec ed du ing h ee consecu i e days in
each PCC, be ween Feb ua y and Ma ch 2007, by using
wo me hods: a able PC (elec onic pencil equi ed)
and a ouch sc een panel (nei he mouse no pencil
necessa y). Subjec s comple ed a e y sho ini ial ques-
ionnai e abou hei age, sex and whe he hey had su -
e ed any o he ch onic condi ions p esen ed in a
checklis including: anxie y, dep ession, acu e disease,
a e ial hype ension, ca diac disease, diabe es, join
pain, mig aine, pulmona y disease and “o he diseases”.
The pa ien s illed his ch onic condi ions checklis on
hei own. In addi ion, he SF-12 Heal h Su ey was
adminis e ed using he same de ices [23-25]. CAT-
Heal h and SF-12 comple ion imes we e au oma ically
eco ded.
The CAT-Heal h sys em
The CAT-Heal h sys em e alua es he gene ic HRQoL
o heal hy o ill subjec s om he gene al popula ion by
showing a a iable numbe o i ems (be ween 5 and 15),
ex ac ed om a unidimensional calib a ed pool o 96
i ems which had been p e iously de eloped [22]. All he
i ems in he pool ha e 5 esponse ca ego ies. The i s
Rebollo e al.Heal h and Quali y o Li e Ou comes 2010, 8:147
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i em is andomly selec ed among 13 ini ial i ems which
co e a b oad ange o he measu ed cons uc
(HRQoL) and which ocus on gene ic heal h aspec s.
These 13 ini ial i ems we e selec ed among he mos
in o ma i e i ems by an expe panel Based on he
esponse o his i s ques ion, he sys em selec s he
mos in o ma i e i em o be p esen ed as he ollowing
ques ion, i e a i ely. The sys em s ops when ei he : 1)
he maximum numbe o i ems (n = 15) has been p e-
sen ed o he subjec ; o 2) he minimum numbe o
i ems has been achie ed, he es ima ion e o is below
he uni y and he pe cen age o educ ion o he e o ,
wi h espec o he p e ious es ima ion, is below 5%.
This applica ion me hod was heo e ically es ed by
meanso asimula ions udy[22]andi p o idedan
accu a e sco e o mode a ely low o high HRQoL le els
(nea o gene al popula ion mean sco e). The sco e cal-
cula ed by CAT-Heal h sys em has a heo e ical ange
be ween -3.85 and +3.87, bu i was no malized o a
50 ± 10 dis ibu ion, in o de o acili a e i s in e p e a-
ion:(CATsco e-mean)/SD*10+50.Thehighe he
sco e, he be e he HRQoL.
E alua ion o he CAT-Heal h sys em
CAT-Heal h was e alua ed conside ing h ee di e en
c i e ia: 1) easibili y o he sys em in he clinical p ac-
ice, in e ms o comple ion ime and es leng h, paying
special a en ion o elde ly subjec s ( ou h qua ile o
he dis ibu ion). 2) Psychome ic e alua ion, including
con en ange co e age, I em Exposu e Ra e (IER) and
es p ecision; and 3) Validi y assessmen o CAT-
Heal h. Cons uc alidi y was s udied h ough he ana-
lysis o di e ences in CAT-Heal h sco es depending on
sex ( emales we e expec ed o ha e wo se sco es han
males), age (elde ly people we e expec ed o show wo se
sco es) and he p esence o epo ed ch onic condi ions
( he highe he numbe o condi ions, he wo se he
sco e). I was also hypo hesized ha subjec s wi h one
o he lis ed pa hologies should ha e a wo se sco e han
subjec s wi hou hem. Mig aine, acu e pa hology,
hype ension and “o he pa hologies”, howe e , we e no
conside ed o be associa ed o HRQoL a p io i, because
he con en o he i ems was no designed o ake in o
accoun acu e o silen pa hologies. Finally, CAT-Heal h
con e gen alidi y was e alua ed wi h espec o SF-12
physical and men al componen sco es. A mode a e co -
ela ion be ween bo h ques ionnai es was expec ed (co -
ela ion coe icien s be ween 0.3 and 0.6), as i is usually
ound when HRQoL gene ic ques ionnai es a e com-
pa ed [26-28]
S a is ical analysis
Absolu e and ela i e equencies we e used o desc ibe
he sample dis ibu ion wi h espec o he nominal
a iables (sex and decla ed pa hologies). Mean and s an-
da d de ia ion we e used o he con inuous a iables
(age, CAT-Heal h and SF-12 sco es, and numbe o
decla ed pa hologies). Qua iles we e used in he case o
he CAT-Heal h comple ion imes and es leng h. Di -
e ences in he numbe o i ems shown o subjec s,
acco ding o age and ch onic condi ions, we e assessed
by means o a K uskal-Wallis es . Di e ences acco ding
o sex we e e alua ed by means o a Mann-Whi ney
es .
Con en ange co e age o CAT-Heal h was s udied
h ough he analysis o loo and ceiling e ec s. I em
Exposu e Ra e (IER) was de ined as he a io o he o al
numbe o imes a gi en i em is shown o he numbe
o imes CAT-Heal h was adminis e ed. Tes p ecision
was s udied h ough he analysis o he Tes In o ma ion
Func ion (TIF), which is an agg ega e o he in o ma ion
p o ided by each i em. Conside ing he adap i e na u e
o he sys em and ha he numbe o i ems shown
wi hin each es we e limi ed o 15, a TIF using all he
i ems in he pool is no ep esen a i e o a ypical es ,
so a TIF was cons uc ed by using jus he 15 i ems
which p o ided mo e in o ma ion a each le el (gi en
his was a con inuous ange, a p ocess o disc e iza ion
was necessa y and 800 HRQoL le els we e conside ed).
No e ha he selec ion o i ems migh change wi hin
he HRQoL ange.
Di e ences in CAT-Heal h sco es be ween males and
emales and be ween subjec s who decla ed ha ing any
o he lis ed pa hologies we e assessed by means o a
es . Lineal eg ession analysis was pe o med o con-
i m he associa ion o each o he pa hologies indepen-
den ly wi h he CAT-Heal h sco e. Co ela ion be ween
CAT-Heal h sco es and age and he numbe o pa holo-
gies was analyzed by means o Pea son and Spea man
co ela ion coe icien s, espec i ely. The sample was
di ided in o 4 g oups, acco ding o he numbe o
decla ed pa hologies (none, 1, 2, 3 o mo e) and also
acco ding o he qua iles o he dis ibu ion o age;
CAT-Heal h and SF-12 sco es we e compa ed among
hese g oups by means o One-Way ANOVA. E ec size
was compu ed o CAT-Heal h sco e and he physical
and men al componen s o SF-12, when compa ing
mean di e ences be ween g oups (age, sex and numbe
o pa hologies): Cohen’sdin he case o a es and e a
squa e in hecaseo ANOVA.Following heguidelines
p oposed by Cohen [29], o es s, an e ec size o 0.1
was conside ed small, 0.3 was conside ed medium
and 0.5 was la ge. In he case o ANOVA, 0.01, 0.06
and 0.14 we e conside ed small, medium o la ge,
espec i ely.
Co ela ions be ween he CAT-Heal h sco e and he
SF-12 physical and men al componen s we e assessed by
means o Pea son co ela ion coe icien s.
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Resul s
The cha ac e is ics o he sample (N = 396) a e
desc ibed in Table 1. The mean age (SD) was 48.6
(17.7) yea s and wo hi ds o he subjec s we e emale.
Mo eo e , one hi d o he pa icipan s did no epo
any ch onic condi ion om he lis .
Rega ding he analysis o he p ac ical use o CAT-
Heal h, he median comple ion ime o CAT-Heal h was
81 seconds (IQ ange = 59 seconds-118 seconds),
inc easing wi h age (p < 0.001) om 66 seconds in he
g oup o subjec s aged unde Pc25 o 107 seconds in
he g oup o subjec s aged o e Pc75. The median num-
be o he CAT-Heal h i ems shown o subjec s was 8
(IQ ange = 6-10). The e we e no s a is ically signi i-
can di e ences (p > 0.05) in he numbe o i ems
shown o males and emales, o subjec s om di e en
age g oups and o subjec s acco ding o he numbe o
decla ed pa hologies.
The CAT-Heal h non-no malized sco e anged
be ween -2.4 and +2.8 ( heo e ical ange be ween -3.8
and +3.8). Nei he ceiling no loo e ec s we e ound.
The mean no malized sco e was 50.88 (6.02), wi h a
minimum o 34.71 and a maximum o 80.89. The mean
Physical Componen Summa y (PCS) sco e o SF-12 was
46.84 (10.1) and i anged be ween 19.12 and 67.06; he
mean Men al Componen Summa y (MCS) sco e was
46.88 (10.96), anging be ween 11.18 and 67.83.
Figu e 1 shows CAT-Heal h I em Exposu e Ra e (IER).
None o he i ems in he pool had an exposu e a e o
100%, while 36 i ems (37.5%) we e no shown a any
ime (20 o hem could no be shown wi h he chosen
applica ion me hod). IER was o e 5% o 26 i ems
(27.1%). The bes -15 TIF is shown in Figu e 2 along
wi h he s anda d e o o each le el o he scale. The
Tes In o ma ion Func ion (TIF) peaked be ween le el
-1 and 0 o HRQoL, which co esponds o he no mal-
ized sco es 35.58 and 52.19. In his pa o he scale, he
e o was below 0.2.
Rega ding cons uc alidi y, in Table 2 he compa i-
son o CAT-Heal h and SF-12 sco es is shown wi h
espec o sex, age and he numbe o decla ed pa holo-
gies. CAT-Heal h and SF-12 MCS sco es we e highe
o males han o emales (p < 0.0001). The e ec size
(ES) o CAT-Heal h (0.46) was simila o ha o MCS
(0.51) and highe han ha o PCS (0.12). The CAT-
Heal h sco e showed a nega i e s a is ically signi ican
co ela ion wi h age ( = -0.351; p < 0.001) as SF-12
PCS did ( = -0.255; p < 0.001); SF-12 MCS did no
show a s a is ically signi ican co ela ion wi h age. By
di iding he sample in ou age g oups (unde 34.27
yea s; 34.27-46.26; 46.27-61.19; o e 61.19), ANOVA
analysis showed s a is ically signi ican di e ences (p <
0.0001) among age g oups o CAT-Heal h and PCS
sco es. The CAT-Heal h sco e also showed a nega i e
s a is ically signi ican co ela ion wi h he numbe o
pa hologies decla ed by he esponden s ( = -0.548; p <
0.01), like PCS and MCS ( = -0.337 and = -0.262,
espec i ely; p < 0.01). The ES o CAT-Heal h (0.12)
was highe han hose o PCS (0.06) and MCS (0.01).
Figu e 3 shows he CAT-Heal h sco es o subjec s
who decla ed su e ing om any o he lis ed pa holo-
gies and o hose who did no . Di e ences we e all s a-
is ically signi ican (p < 0.05), excep ha o acu e
pa hology and mig aine. These di e ences emained
Table 1 Sample desc ip ion (N = 396)
Sample desc ip ion
All (N = 396) Male (N = 130) Female (N = 266)
Mean age (SD) 48.61 (17.67) 49.03 (18.45) 48.40 (17.30)
F equency o decla ed pa hologies: n (%)
Anxie y 70 (17.7%) 11 (8.5%) 59 (22.2%)
Dep ession 56 (14.1%) 5 (3.8%) 51 (19.2%)
Acu e pa hology 98 (24.7%) 31 (23.8%) 67 (25.2%)
A e ial hype ension 66 (16.7%) 23 (17.7%) 43 (16.2%)
Ca diac disease 32 (8.1%) 13 (10%) 19 (7.1%)
Diabe es 37 (9.3%) 19 (14.6%) 18 (6.8%)
Join pain 125 (31.6%) 32 (24.6%) 93 (35%)
Mig aine 36 (9.1%) 5 (3.8%) 31 (11.7%)
Pulmona y disease 31 (7.8%) 13 (10%) 18 (6.8%)
O he pa hology 85 (21.5%) 34 (26.2%) 51 (19.2%)
Numbe o sel - epo ed condi ions
036.9% 43.1% 33.8%
133.8% 36.2% 32.7%
216.4% 12.3% 18.4%
3 o mo e 12.9% 8.4% 15.1%
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s a is ically signi ican when analysing each o he
pa hologies adjus ing by he es o hem in a eg ession
analysis. SF-12 PCS did no de ec di e ences be ween
pa ien s wi h o wi hou anxie y, dep ession, acu e dis-
ease, pulmona y disease and mig aine; nei he did SF-12
MCS de ec di e ences in he case o diabe es, acu e
disease, ca diac disease, pulmona y disease, a e ial
hype ension and “o he disease”.
The co ela ion coe icien s be ween CAT-Heal h
sco es and SF-12 PCS ( = 0.547) and MCS ( = 0.346)
we e mode a e and s a is ically signi ican (p < 0.001).
Discussion
Se e al compu e -adap i e es s (CAT) e alua ing heal h
ou comes ha e been de eloped and alida ed in ecen
yea s, bu , o ou knowledge, he CAT-Heal h sys em is
one o he i s CATs designed o e alua e gene ic
HRQoL.The esul so hep esen s udyshow ha
CAT-Heal h is easible, alid and e icien o HRQoL
e alua ion: i s psychome ic p ope ies we e sa is ac o y
when e alua ing HRQoL in a wide ange o subjec s
a ending p ima y ca e se ings.
The use o HRQoL as a heal h ou come measu e is
becoming mo e impo an in he e alua ion o pa ien
ca e and heal h se ices. I is usually e alua ed using
ques ionnai es based on CTT, adminis e ed h ough
pencil and pape . Once he answe s o a subjec a e
collec ed, he ques ionnai e has o be coded and
sco ed, and hen he esul s ha e o be in e p e ed.
This is a ime consuming p ocess and, he e o e, i is
expensi e, especially o ollow-ups in clinical p ac-
ice. These p oblems cons i u e a ba ie ha p e en s
he e alua ion o HRQoL in he clinical se ing [3].
CAT ins umen s clea ly inc ease “measu emen e i-
ciency”( he a io o a measu e’s psychome ic
Figu e 1 The CAT-Heal h I em Exposu e Ra e (IER). The IER is he a io o he o al numbe o imes one i em is p esen ed o he numbe o
imes CAT-Heal h is adminis e ed.
Figu e 2 The CAT-Heal h bes -15 Tes In o ma ion Func ion
(TIF). The TIF is used o e alua e he es p ecision o di e en
HRQoL le els.
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soundness o he esponse bu den he measu es
imposes) [7]. CAT ins umen s dec ease he esponse
bu den, diminishing he numbe o ques ions o be
answe ed by he subjec ; hey ha e small loo and
ceiling e ec s, when hey use an ex ensi e i em bank;
hey educe he e o o measu emen and so hey
measu e much mo e accu a ely; hey a e lexible,
adap ing hemsel es o he ai le el o he espon-
den and also o speci ic measu emen con ex s
[11-20].
Table 2 Compa ison o he CAT-Heal h and SF-12 sco es acco ding o sex, age and numbe o sel - epo ed condi ions
Compa ison o he CAT-Heal h and SF-12 sco es acco ding o sex, age and numbe o decla ed pa hologies
CAT-Heal h SF-12 PCS SF-12 MCS
Sex Male (N = 130) 52.68 (6.51) 47.65 (9.43) 50.89 (9.45)
Female (N = 266) 49.99 (5.56) 46.44 (10.40) 44.92 (12.57)
p( es ) < 0.0001 0.262 < 0.0001
E ec size (Cohen’sd) 0.455 0.120 0.513
Age < 34.27 yea s (N = 100) 53.96 (5.69) 50.46 (7.98) 47.59 (11.19)
34.27-46.26 yea s (N = 98) 51.33 (5.53) 47.82 (10.42) 47.24 (11.65)
46.27-61.19 yea s (N = 99) 49.66 (5.29) 44.83 (10.32) 45.36 (12.30)
> 61.19 yea s (N = 99) 48.54 (6.18) 44.20 (10.36) 47.34 (12.70)
p (ANOVA) < 0.0001 < 0.0001 0.537
E ec size (e a squa e) 0.116 0.062 0.006
Numbe o sel - epo ed condi ions None (N = 146) 54.23 (5.72) 50.56 (7.84) 50.80 (9.04)
1 pa hology (N = 134) 50.89 (4.86) 46.74 (10.23) 46.52 (12.40)
2 pa hologies (N = 65) 47.75 (7.42) 44.14 (10.81) 42.78 (12.70)
3 o mo e pa hologies (N = 51) 45.24 (4.66) 39.85 (9.97) 41.86 (13.59)
p (ANOVA) < 0.0001 < 0.0001 < 0.0001
E ec Size (e a squa e) 0.272 0.124 0.082
es : *
(
p<0.05
)
**
(
p<0.001
)
Figu e 3 Di e ences in he CAT-Heal h sco es acco ding o sel - epo ed condi ions (means and 95% con idence in e als).
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His o ically, HRQoL has been conside ed a mul i-
dimensional concep . Some au ho s a gue, howe e , ha
he e is an unde lying cons uc ha a ec s all hem
and can be di ec ly measu ed [30]. In a p e ious pape ,
we p esen ed he de elopmen and calib a ion o a gen-
e ic HRQoL i em bank, so ha he assessmen o
HRQoL wi h a single dimension was easible [22]. Using
ha i em bank, we de eloped one o he i s IRT-based
CATs o he e alua ion o gene ic HRQoL, he alida-
ion o which we ha e p esen ed in his manusc ip .
The e alua ion o CAT-Heal h has shown ha CAT-
Heal h sys em median comple ion ime is eally sho
(unde 1minu eandahal ).E en houghweha e
shown ha he comple ion ime was associa ed wi h he
age o he esponden s (i mus be aken in o accoun
ha elde ly people a e no amilia wi h he in e aces
used o ill in he ques ionnai e), he median comple ion
ime o he g oup o indi iduals in he las qua ile o
age (o e 61.19 yea s) was s ill well benea h 2 minu es.
Also, he e alua ion o gene ic HRQoL wi h CAT-heal h
equi ed a median o 8 i ems, a es leng h simila o
ha o published CATs o speci ic g oups o pa holo-
gies: AM-PAC-CAT [16], o pos -acu e ca e, showed a
mean o 6.6 i ems; each o he 5 domains o he CAT-
5D-QOL [15], o back pain, 4.4 o 6.6 i ems; and he
Anxie y-CAT [18] 6 o 8 i ems.
In his alida ion s udy, 60 i ems we e shown a leas
once, which ep esen s he 79% o he i ems in he pool
ha could be shown, acco ding o he chosen applica-
ion me hod (a leas 20 i ems will ne e appea , as hey
a e no amongs he 15 mos in o ma i e o any
HRQoL le el). The ac ha none o he i ems had an
IER o 100% and ha he numbe o di e en i ems
used a some poin was high indica es ha he sys em
ac ually adap ed he i ems p esen ed o he indi iduals
in he sample, poin ing o he adequacy o a CAT o
HRQoL measu emen .
Wi h espec o he con en ange co e age o CAT-
Heal h, he equency dis ibu ions o he non-no mal-
ized sco es o he subjec s unde s udy we e no mally
dis ibu ed, wi h no loo no ceiling e ec s, as
expec ed o a gene ic ins umen in his sample. On
he con a y, he abo emen ioned domain-speci ic
CATs p esen ed ceiling e ec s: 10% o AM-PAC-
CAT [16] ( ha p esen ed a oughly no mally dis ibu-
ed sco e) and 0% o 6.1% o he di e en CAT-5D-
QOL scales [15]. No malized CAT-Heal h sco es (50
± 10) had a simila ange o hose o SF-12 PCS and
sligh ly na owe han hose o MCS. The pe o -
mance o CAT-Heal h in HRQoL assessmen in he
s udied sample, which co e ed a b oad spec um o
indi iduals a ending p ima y ca e se ings, indica es a
good po en ial o he e alua ion o he gene al
popula ion.
The analysis o he TIF showed ha CAT-Heal h is a
e y disc imina i e measu emen ool in he ange o
sco es be ween 35 and 52, which co esponds o a no -
mal o sligh ly de e io a ed HRQoL, he mos equen
s a us in people who demand heal h ca e a a p ima y
ca e cen e. Fu u e esea ch is needed in o de o add
new i ems o he pool which would allow CAT-Heal h
o co e a b oade ange o HRQoL.
The analysis o alidi y demons a ed ha he CAT-
Heal h sco e is a alid gene ic measu e o HRQoL.
CAT-Heal h adequa ely de ec s he hypo hesized di e -
ences be ween male and emale subjec s, as well as
be ween di e en age g oups and among g oups by he
numbe o decla ed pa hologies.
Recen ly, he Adap i e Measu emen o Change
(AMC) has been p oposed as a easible and e ec i e
me hod o measu ing indi idual change using CATs
[31]. The a ailabili y o an e o es ima e o each sub-
jec , in his ype o measu emen s, u ns high he p eci-
sion o CATs, like CAT-Heal h, in o use ul ins umen s
o moni o ing HRQoL. The sensi i i y o change o
CAT-Heal h will be add essed in he u u e by means o
a longi udinal s udy. The alida ion o he sys em in a
b oade andom sample o he gene al popula ion and
he adap a ion o i s use in English a e also planned.
These s udies will include a la ge numbe o clinical
a iables o allow o a de ailed e alua ion o he con-
s uc alidi y o he sys em.
Conclusions
Al hough domain speci ic CATs exis o a ious a eas o
HRQoL, CAT-Heal h is one o he i s IRT-based CAT
designed o e alua e gene ic HRQoL and i has p o en
easible, alid and e icien , when adminis e ed o a b oad
sample o indi iduals a ending p ima y ca e se ings.
The educed numbe o i ems equi ed o HRQoL
e alua ion and he esul ing sho ened comple ion ime,
oge he wi h he cha ac e is ics inhe en o compu e -
ized ins umen s, such as au oma ic sco ing and in e -
p e a ion o esul s, make o CAT-Heal h a p ac ical
ins umen o clinical se ings, as P ima y Ca e Cen es.
These wo ac s, along wi h i s sound psychome ic
p ope ies, which open he possibili y o e alua ing
HRQoL changes a he indi idual le el, a e impo an
ad an ages o he CAT-Heal h sys em o e o he gen-
e ic ques ionnai es based on CTT.
No e
The Spanish C.A.T-Heal h g oup is o med by esea ch-
e s om:
BAP Heal h Ou comes Resea ch, O iedo, Spain; 4
h
A ea P ima y Ca e Cen e s, P incipali y o As u ias
Heal h Se ice, O iedo, Spain; Uni e sidad de O iedo,
Psychology Depa men , O iedo, Spain; Uni e sidad
Rebollo e al.Heal h and Quali y o Li e Ou comes 2010, 8:147
h p://www.hqlo.com/con en /8/1/147
Page 7 o 8
Complu ense de Mad id, Me hodology Depa men ,
Mad id, Spain; Ins i u Municipal d’In es igació Mèdica
(IMIM-Hospi al del Ma ), Heal h Resea ch Uni Se -
ices, Ba celona, Spain.
Acknowledgemen s
The au ho s would like o hank he Heal h Di ec o o he 4 h A ea P ima y
Ca e Can e s o As u ias and all he GPs and polls e s o he P ima y Ca e
Cen es ha pa icipa ed in his s udy: “El C is o”,“Collo o”,“Paulino P ie o”,
“Puma ín”,“Tea inos”,“Vallobín-Concinos”and “Ven anielles”. Thanks, also, o
all he pa ien s who kindly spen some minu es o hei ime o comple e
he ques ionnai e and o Ad iana Pé ez o he p oo eading o his a icle.
Au ho de ails
1
BAP Heal h Ou comes Resea ch, Calle Azcá aga 12 A, 33010, O iedo, Spain.
2
Uni e sidad de O iedo, Psychology Depa men , Plaza Feijoo s/n, 33003,
O iedo, Spain.
3
Ins i u Municipal d’In es igació Mèdica (IMIM-Hospi al del
Ma ), Doc o Aiguade 88, 08003, Ba celona, Spain.
4
CIBER en Epidemiología
y Salud Pública (CIBERESP), Doc o Aiguade 88, 08003, Spain.
Au ho s’con ibu ions
All au ho s a e esponsible o he epo ed manusc ip and ha e
pa icipa ed in i s concep and design, analysis and in e p e a ion o da a
and, inally, in i s d a ing and e iew.
Compe ing in e es s
The au ho s he eby decla e ha he e is no con lic o in e es s, inancial
ag eemen o o he in ol emen wi h any company whose p oduc igu es
in he submi ed wo k. Pablo Rebollo, Ignacio Cas ejón, Jesús Cue o,
Guille mo Villa and Helena Díaz-Cue o wo k a BAP Heal h Ou comes
Resea ch, which is he Applican o a Spanish pa en applica ion
(P200701072) and a Eu opean pa en applica ion (EPO8013312) ela ed o
he CAT-Heal h sys em.
Recei ed: 4 June 2010 Accep ed: 3 Decembe 2010
Published: 3 Decembe 2010
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doi:10.1186/1477-7525-8-147
Ci e his a icle as: Rebollo e al.: Valida ion o a compu e -adap i e es
o e alua e gene ic heal h- ela ed quali y o li e. Heal h and Quali y o
Li e Ou comes 2010 8:147.
Rebollo e al.Heal h and Quali y o Li e Ou comes 2010, 8:147
h p://www.hqlo.com/con en /8/1/147
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