The Health Assessment Questionnaire (HAQ)

Abstract

Patient-reported outcomes (PROs) provide intrinsic knowledge about a patient's health, functional status, symptoms, treatment preferences, satisfaction, and quality of life. They have become an established approach for assessing health outcomes. The Health Assessment Questionnaire (HAQ), introduced in 1980, is among the first PRO instruments designed to represent a model of patient-oriented outcome assessment. The HAQ is based on five patient-centered dimensions: disability, pain, medication effects, costs of care, and mortality. It has been validated by mail, in the office, by telephone, and by comparison with paraprofessional and physician judgments as a reliable instrument, and has been significantly correlated with other PRO instruments. Typically, one of two HAQ versions is used: the Full HAQ, which assesses all five dimensions, and the Short or 2-page HAQ, which contains only the HAQ disability index (HAQ-DI) and the HAQ's patient global and pain visual analog scales (VAS). The HAQ-DI and the global and pain VAS (i.e., the short HAQ) have essentially retained their original content since their inception, while the Full HAQ undergoes periodic revision to address issues of contemporary scientific interest. The HAQ-DI has been translated or culturally adapted into more than 60 different languages or dialects and has become part of the National Institutes of Health "Road-map" Project, the Patient-Reported Outcomes Measurement Information System (PROMIS).

Full text

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Division of Immunology & Rheumatology,
School of Medicine, Stanford University,
Palo Alto, California, USA.
Bonnie Bruce, DrPH, MPH, RD, Senior
Research Scientist; James F. Fries, MD,
Professor of Medicine.
Please address correspondence to: Dr.
Bonnie Bruce, Division of Immunology
& Rheumatology, School of Medicine,
Stanford University, 1000 Welch Road,
Suite 203, Palo Alto, California 94304,
USA.
E-mail: bbruce@stanford.edu
This was supported in part by grants AR-
43584 and AR052158 from the National
Institutes of Health (NIH).
Clin Exp Rheumatol 2005; 23 (Suppl. 39):
S14-S18.
© Copyright CLINICAL AND EXPERIMENTAL
RHEUMATOLOGY 2005.
Key words: Health Assessment
Questionnaire, HAQ, Physical
Function, HAQ-DI, Patient Reported
Outcomes, Arthritis, Rheumatism and
Aging Medical Information System,
ARAMIS
ABSTRACT
P a t i e n t - re p o rted outcomes (PROs) pro -
vide intrinsic knowledge about a pa -
tient’s health, functional status, symp -
toms, treatment pre f e rences, satisfac -
tion, and quality of life. They have be -
come an established approach for as -
sessing health outcomes. The Health
Assessment Questionnaire (HAQ), intro-
duced in 1980, is among the first PRO
i n s t ruments designed to re p resent a mo -
del of patient-oriented outcome assess -
ment. The HAQ is based on five patient-
c e n t e red dimensions: disability, pain,
medication effects, costs of care, and
m o rtality. It has been validated by mail,
in the office, by telephone, and by com -
parison with paraprofessional and phy -
sician judgments as a reliable instru -
ment, and has been significantly corre -
lated with other PRO instruments. Typ -
i c a l l y, one of two HAQ versions is used:
the Full HAQ, which assesses all five
dimensions, and the Short or 2-page
H A Q , which contains only the HAQ dis -
ability index (HAQ-DI) and the HAQ’s
patient global and pain visual analog
scales (VAS). The HAQ-DI and the glo -
bal and pain VAS (i.e., the short HAQ)
have essentially retained their original
content since their inception, while the
Full HAQ undergoes periodic revision
to address issues of contemporary sci -
entific interest. The HAQ-DI has been
translated or culturally adapted into
m o re than 60 different languages or
dialects and has become part of the
National Institutes of Health “Road -
map” Project, the Patient-Reported Out -
comes Measurement Information Sys -
tem (PROMIS).
Introduction
Improving health outcomes is among
the most important challenges of our
society (1). Use of patient reported out-
comes (PROs) has become an estab-
lished approach to help tackle these
challenges. PROs provide fundamental
knowledge about a patient’s health,
functional status, symptoms, treatment
preferences, satisfaction and quality of
life from their own personal perspec-
tive. A c c o r d i n g l y, self-reported mea-
sures help to inform patient assess-
ment, diagnosis determination, care
planning, and the evaluation of pro-
gress towards treatment goals. T h e
Health Assessment Questionnaire
(HAQ), published in 1980 by the Stan-
ford Arthritis Center (2), is among the
first PRO instruments that was initially
designed to represent a model of
patient-oriented outcome assessment.
The HAQ, which assesses multiple
dimensions based on patient-centered
values, is one of the most cited and
employed PRO instruments, particular-
ly but not exclusively in the rheumatic
disease literature. The original article is
a citation classic (2).
Through many demonstrations of its
r e l i a b i l i t y , validity, adaptability, and ease
of use, the HAQ has played a major
role in the paradigm shift from reliance
on biochemical and physical measure-
ments to emphasis on outcomes that
are relevant to the patient. The HAQ
has been successfully implemented in
numerous diverse areas, such as predic-
tion of successful aging, inversion of
the therapeutic pyramid in rheumatoid
arthritis (RA), quantification of nons-
teroidal anti-inflammatory drug gas-
t r o p a t h y, development of risk factor
models for osteoarthrosis, and exami-
nation of mortality risks in RA(3).
The HAQ: Ahierarchial basis
Creation of the HAQ was based on
studies of patient-centered health val-
ues that have tended to yield five gen-
eric outcome dimensions. Patients re-
port that they want: 1) to avoid disabil-
ity; 2) to be free of pain and discom-
fort; 3) to avoid adverse effects of treat-
ment; 4) to keep medical costs low; 5)
and to postpone death (4-7). Altogeth-
e r, these five dimensions along with
more specific sub-categories form the
HAQ’s hierarchial structure (Fig. 1).
At the apex of the HAQ’s hierarchy is
the overall entity of global health, which
is a function of the five dimensions. To
operationalize global health without sa-
crificing patient information, the HAQ’s
The Health Assessment Questionnaire (HAQ)
B. Bruce, J.F. Fries

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The Health Assessment Questionnaire / B. Bruce & J.F. Fries
five dimensions are further subdivided
into more discrete categories that ap-
pear lower in the hierarchy. For exam-
ple, the measurement of physical func-
tion is calculable from specific ques-
tions at a lower level that include activ-
ities which involve the upper extremi-
ties, lower extremities, or both.
A l t e r n a t i v e l y, rather than assess the
five dimensions individually, a single
global outcome question can be direct-
ly asked using an analog scale. Such a
question will capture in part the pa-
tient’s trade-offs between the different
outcome dimensions, but will also be a
broader perspective that may include
other idiomatic values such as spiritu-
ality, disability-friendly environments,
and family support. Instruments that
use a single-item global health visual
analog scale (VAS) have been recom-
mended as representing meaningful out-
comes and have been suggested inter-
nationally as one of the six core patient
outcomes (i.e., disability, pain, patient
global, physician global, swollen joint
count, and tender joint count) to be
measured in clinical studies of rheuma-
toid arthritis (RA) (8-10). Several scales,
including the HAQ, contain such a
scale (11-13).
The “Short” or“2-page” or t h e
“Full” HAQ: W h a t ’s the diff e rence ?
Over its more than two decades of use,
the meaning of the term “HAQ” has
been interpreted differently. Typically,
it refers to one of two versions. The
Full HAQ assesses all five dimensions
of health outcome which includes drug
side effects and medical costs, as well
as supplemental sections on demogra-
phics, lifestyle and health behaviors,
while the S h o rt or 2-page HAQ i s
comprised of only the HAQ disability
index (HAQ-DI) and the HAQ’s pa-
tient global and pain VAS. In the Full
HAQ, drug side effects, dollar costs
and other items are periodically tai-
lored and supplemented with additional
questions when contemporary issues,
specific hypotheses or research ques-
tions arise by ARAMIS or other inves-
tigators, while the HAQ-DI and the
patient global and pain VAS have re-
main unchanged.
The Full HAQ was one of the first in-
struments deliberately designed to cap-
ture prospectively and by protocol the
long-term impact of chronic illness. It
is generic in nature and was developed
initially for use in multiple illnesses so
that the impact of different disease pro-
cesses could be compared, although
much of its early work emanated from
the rheumatology field. In its early
development, the full HAQ was origi-
nally called the “Arthritis Assessment
Questionnaire” or “AAQ”. However,
after it was recognized that the five
patient-centered outcome dimensions
represented general concepts and were
not restricted to any single specific dis-
ease area, the current HAQ name was
adopted. In all, the HAQ was designed
to be efficient, structured for practical
application during clinic visits, and
compatible with high return rates when
administered by mail or telephone.
The Full HAQ was adopted by the
Arthritis, Rheumatism, and A g i n g
Medical Information System (ARA-
MIS) in 1980 and has been deployed
more than 100,000 times by our unit to
assess clinical status, evaluate eff e c-
tiveness in clinical and observational
trials, and to define health outcomes
(3). Amyriad of populations have been
studied with the HAQ: among them are
HIV/AIDS patients, normal aging pop-
ulations,adults and children with rheu-
matic diseases, and disabled workers
(14-18).
Nonetheless, overall, it has been the
Short or 2-page HAQ or the HAQ-DI
that has received the widest attention,
most frequent use, and that is most
commonly referred to as “the HAQ.”
The short HAQ permits an expedient
assessment of three of the six American
College of Rheumatology (ACR) out-
come measures for rheumatoid arthritis
(9). It can be self-administered in five
minutes and scored in less than one
minute. But as with any instrument, it
has limitations, and as generally used
does not capture disability associated
with sensory organ dysfunction or psy-
chiatric dysfunction and does not di-
rectly measure patient satisfaction or
social networking. However these vari-
ables, or other variables of interest to
the user, can be readily appended as
separate items.
The short HAQ has been employed in
population-based studies, including the
follow-up to the National Health and
Nutrition Examination Survey (NHA-
NES) (19). It has also been adminis-
tered in a variety of diseases and condi-
tions, including osteoarthritis, juvenile
rheumatoid arthritis, systemic lupus
erythematosus, ankylosing spondylitis,
fibromyalgia, psoriatic arthritis, and
systemic sclerosis (3).
Both the short and the full HAQ are
copyrighted for the purposes of insur-
ing that they will be used unmodified to
preserve validity and contribute to stan-
Fig. 1. The hierarchy of patient outcome.

dardization of assessment across stud-
ies. However, the HAQ is considered to
be in the public domain, and permis-
sion for its use is customarily given
without charge. A “ H A Q - PAK” con-
taining a recent version of the Full
HAQ (which includes the short HAQ)
and scoring directions is available on
the ARAMIS website at A R A M I S .
Stanford.edu.
HAQ-DI: Development and
validation
The physical function scale of the
HAQ, the HAQ-DI, was the original
HAQ section to be developed and vali-
dated in the late 1970s under the aus-
pices of the Stanford Arthritis Center. It
was created by parsing questions and
components from a variety of instru-
ments extant at the time (20). T h e
HAQ-DI evolved over numerous itera-
tions through a series of subjective and
objective assessments. Statistical eval-
uation, physician appraisal, and patient
feedback modalities were used in the
developmental process (2, 20). A com-
prehensive validation of each item set
was performed to yield the final instru-
ment. Correlation matrices were con-
structed, and inter-correlations, item-
total correlations, correlations with
existing “gold standards” such as per-
formance of activities of daily living,
physiological and biochemical mea-
sures, and chart reviews were evaluat-
ed. Items with correlations of ≥0.90
and those with correlations of ≤0.50
were deleted, since such items did not
accurately measure the dimension rep-
resented by the other items in the index
or had ambiguous, inconsistent or in-
complete responses. Additional details
of the development of the HAQ-DI are
described in Fries, Spitz, Kraines, and
Holman (1980) (2) and Fries, Spitz and
Young (1982) (20).
The HAQ-DI has been repeatedly vali-
dated as a reliable PRO instrument by
mail, in the office, by telephone, and by
comparison with paraprofessional and
physician judgments (2). Evaluations
of the psychometric properties of the
HAQ-DI have provided consistent and
substantial demonstrations of both its
reliability and validity across many ap-
plications and in different patient popu-
lations and are reported in detail with
related publications (3, 18). Test-retest
correlations demonstrating reprodu-
cibility have ranged from 0.87 to 0.99,
and correlations between interview and
questionnaire formats have ranged
from 0.85 to 0.95. Validity has been de-
monstrated in numerous studies. There
is consensus that the HAQ-DI posses-
ses face and content validity, and corre-
lations between questionnaire or inter-
view scores and task performance have
ranged from 0.71 to 0.95 demonstrat-
ing criterion validity. The construct/
convergent validity, predictive validity,
and sensitivity to change have also been
established in numerous observational
studies and clinical trials (18). More re-
cently, it was compared with the West-
ern Ontario McMasters Universities
Osteoarthritis Index (WOMAC) and
was found to be similarly and signifi-
cantly correlated (HAQ: R = 0.67, p <
0.0001) (21). In another study of RA
patients by Wolfe (22) that was de-
signed to determine the performance of
distributional characteristics, detection
of functional loss and identification of
change in functional ability – where the
HAQ-DI was compared with the modi-
fied HAQ (MHAQ) and the RA-HAQ
(both shortened versions of the HAQ-
DI) – the HAQ was better at detecting
change and assessing functional ability
than either of the two comparators.
HAQ-DI: Assessment of physical
function
The HAQ-DI includes items that assess
fine movements of the upper extremity,
locomotor activities of the lower ex-
tremity, and activities that involve both
the upper and lower extremities. Stan-
dard scoring takes into account the use
of aids and devices or assistance from
another person. There are 20 items in
eight categories that represent a com-
prehensive set of functional activities –
dressing, rising, eating, walking, hy-
giene, reach, grip, and usual activities.
The stem of each item assesses a
patient’s functional ability using their
usual equipment during the past week.
Each category contains at least two
specific sub-category questions. For
example, under the category “walk-
ing”, patients are asked about their abi-
lity to walk outdoors on flat ground and
to climb up five steps.
Scoring of the HAQ-DI is modeled af-
ter the American Rheumatism Associa-
tion/American College of Rheumatolo-
gy functional classes (23). For each
item, there is a four-level response set
that is scored from 0 to 3, with higher
scores indicating more disability (0 =
without any difficulty; 1 = with some
d i fficulty; 2 = with much diff i c u l t y ;
and 3 = unable to do). To calculate the
HAQ-DI, the highest sub-category score
determines the value for each category,
unless aids or devices are used (see be-
low); there must be responses in at least
6 of the 8 categories or else a HAQ-DI
cannot be computed. The category
scores are then averaged into an overall
HAQ-DI from zero to three. The HAQ-
DI scale has 25 possible values (i.e., 0,
0.125, 0.250, 0.375 … 3). Scores of 0
to 1 generally represent mild to moder-
ate difficulty, 1 to 2 represent moderate
to severe disability, and 2 to 3 indicate
severe to very severe disability. The use
of aids or devices or physical assistance
increases a score of zero or one to a two
to more accurately represent underly-
ing disability; scores at a 3 are not mo-
dified.
The aids used for adjustments by cate-
gory are: dressing – devices used for
dressing (button hook, zipper pull, long
handled shoe horn and so on); rising –
built up or special chairs; eating – built
up or special utensils; walking – canes,
walkers, or crutches; hygiene – raised
toilet seats, bathtub seats, bathtub bars,
long handled appliances in bathroom;
reach – long-handled appliances for
reaching; and grip – jar openers (for
jars previously opened). A complemen-
tary scoring method ignores the scores
for aids and devices when computing
the category scores and represents re-
sidual disability after compensatory
efforts.
In addition, an average of the 20 items
on the HAQ-DI has been used by some
but is not validated well and not recom-
mended. Some investigators interested
in determining the effects of aids and
devices upon disability have scored the
HAQ-DI with and without the aids and
devices questions, and this is accept-
able practice.
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The Health Assessment Questionnaire / B. Bruce & J.F. Fries
The HAQ-DI: Correlations with
other health status measures
The HAQ-DI has been significantly
correlated with other self-report, bio-
chemical and clinical measures, co-
morbidities, health care resource uti-
lization and cost estimations, and mor-
tality (18). Self-report measures that
have been correlated with the HAQ-DI
include the AIMS (24), AIMS2 (25),
Beck Depression Scale (26), Carstairs
Index (27), Nottingham Health Profile
(28, 35), Disease Activity Score (26,
29, 30), Dutch Arthritis Impact Mea-
surement Scale (31), EuroQol (32),
Hollingshead Index (26), Life Event
Interview (33), London Handicap Scale
(34), SF-36 (32, 36, 37), and WOMAC
(21, 32). Correlations with clinical
measures include joint and muscle
activity (14, 38-40), bone health and x-
rays (14, 24, 41, 42), body fat (43, 44),
and health behaviors (43, 45). Bio-
chemical assessments have included C-
reactive protein (30, 46), human leuko-
cyte antigen (HLA) typing (47, 48),
protein mircoarray, rheumatoid factor
and others.
Furthermore, the HAQ-DI has been uti-
lized as a predictor variable in investi-
gations of productivity, morbidity, health
care utilization, health care costs, and
death. The HAQ-DI has been signifi-
cantly correlated with work-related
measures such as work capacity, house-
hold work performance, occupation,
and the ability to live independently
(18,49-52). In investigations related to
health care, the HAQ-DI has been asso-
ciated with a myriad of factors related
to health care utilization such as direct
cost, hospital admissions, length of the
hospital stay, post-surgery delirium, use
of aids and devices in post total knee
replacement surgery and in miscellane-
ous other areas (such as specialty care,
and patient satisfaction with health care
workers) (18, 21, 53).
HAQ-DI: Translations and cultural
adaptations
The HAQ-DI was originally developed
and validated for English-speaking
populations in North America. Since its
inception it has been translated or cul-
turally adapted into more than 60 dif-
ferent languages or dialects, often with
only minor changes. Arecent review in
2003 by Bruce and Fries (3) presents a
resource listing of translations. In gen-
eral, translations and cultural adapta-
tions of the HAQ-DI are usually carried
out by administering investigators.
Translated HAQ-DIs have generally
been fully validated, using methods
such as test-retest reliability, back
translations, item-total correlations,
c o n v e rgent validity, interviewer vs.
self-administered formats, and factor
analyses. To date, culturally adapted
HAQ-DI instruments have proved as
equally reliable and valid as their par-
ent. To adapt the HAQ-DI culturally,
modifications of individual items have
sometimes been necessary. The types
of items most frequently in need of
adaptation have included colloquial
expressions or those for which names
or types of items or utensils are cultur-
ally idiosyncratic. For example, some
cultures do not consume milk in car-
tons; thus, an appropriate substitution
in keeping with the original intent of
the item is made. In some countries a
bathtub is much more commonly used
than is a shower, requiring question
modification. Many translations have
also been performed by the MAPI
Research Institute in Lyon, France, and
the Health Outcomes Group in Palo
Alto, California, both of which have
had extensive experience in translating
and culturally validating the HAQ-DI;
fees are sometimes charged by these
vendors.
The next phase: What’s in store
for the HAQ-DI?
Over its long history, the HAQ-DI has
played an influential role in the para-
digm shift to establishing PROs as
valid, reliable, and responsive hard
data endpoints, and because of its long
history, has enabled the conduct of lon-
gitudinal studies. Although the HAQ-
DI is one of the most studied and wide-
ly used PROs, it – like other instru-
ments – is not ideal and does not uni-
versally meet all needs.
Our group is part of the National Insti-
tutes of Health “Roadmap” project, the
Patient-Reported Outcomes Measure-
ment Information System (PROMIS)
(54). PROMIS is designed to provide
improved assessment of health status
across all chronic illnesses as part of an
improved infrastructure for clinical sci-
ence. As envisioned, PROMIS will im-
prove patient value-based PRO items
with regard to verbal clarity and com-
prehension issues, face validity, patient
relevance, uniqueness, comprehensive-
ness and, finally, psychometric quali-
ties such as degree of difficulty and fit
with a particular content area. Effec-
tiveness of new items will be compared
with more traditional approaches (such
as the HAQ-DI or the SF-36) by clini-
cal trials with particular attention fo-
cused on the ability to detect clinically
important change. Ultimately, the goal
is the ability to compare the results of
PROs across diseases and conditions,
thereby improving treatment and health
outcomes. The HAQ is working to
supercede itself. The new instruments
will permit more precise estimation of
disability and physical function, and
will enable reductions in study sample
sizes while retaining statistical power.
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