213Childhood Health Assessment Questionnaire
The Childhood Health Assessment Questionnaire (CHAQ) [ 5 ] is the principal rheu-
matic “disease-specifi c” instrument to be used for studies involving patients with
JIA and other pediatric rheumatic conditions (JDM, JSLE, etc.) [ 24 , 39 – 44 ]. It mea-
sures functional ability in eight activities of daily living: dressing and grooming,
arising, eating, walking, hygiene, reach, grip, and activities. In the CHAQ, several
questions were added to the HAQ so that there is at least 1 question in each func-
tional area that is relevant to children of all ages under 18. Each of the items within
a single domain has 4 possible categories of answers: “without any diffi culty” (score
0), “with some diffi culty” (score 1), “with much diffi culty” (score 2), and “unable
to do” (score 3). The category “not applicable” was added for the items that may not
apply due to the age of the child. Parents were instructed to take note only of impair-
ment due to the disease in the preceding week. The items with the highest score in
a domain determine the score for that domain, while the use of any aids or devices
or help from another person is assigned a minimum score of 2 for that domain.
These 8 domains are then averaged into a summary score called the disability index
(DI), which may range from 0 to 3 with higher scores meaning higher disability.
The CHAQ also provides an assessment of discomfort using a 10 cm VAS for the
evaluation of pain and a 10 cm VAS for the evaluation of overall well-being.
Since its initial publication, the CHAQ has been translated into many languages
and is used worldwide for assessing children with chronic musculoskeletal diseases
[ 39 ]. A large number of studies have assessed the test–retest reliability, construct
validity, minimal clinically important differences, and quality of the parent-proxy
report of the CHAQ [ 39 , 45 , 46 ]. However, CHAQ has been demonstrated to suffer
from a ceiling effect, with a tendency for scores to cluster at the normal end of the
scale, particularly in patients with fewer joints involved [ 46 , 47 ]. Another problem
with the use of CHAQ is its length and complexity, including the requirement of a
calculator to compute the scores. Mainly for these reasons, although the CHAQ has
been found to have excellent measurement properties, it has remained essentially a
research tool and is not routinely administered in most pediatric rheumatology cen-
ters. It also has been reported that the removal of aids/devices and help from the
CHAQ does not alter the interpretation of disability at a group level, making the
simplifi ed CHAQ a more feasible and valid alternative for the evaluation of disabil-
ity in JIA patients [ 43 ].
For the interpretation of the CHAQ scores, Dempster et al. [ 48 ] reported that the
median CHAQ scores corresponding to mild, mild-to-moderate, and moderate dis-
ability were 0.13, 0.63, and 1.75, respectively. The minimal clinically important
improvement was a reduction in score of 0.13.
Lam et al. [ 49 ] devised three modifi ed versions of CHAQ that measure func-
tional strengths as well as weaknesses (i.e., by using new response scales as well as
by adding more challenging questions) to investigate whether they reduced the
8 PROMs for Juvenile Idiopathic Arthritis