Reliabity and Validity of the Slovak Version and Modification of the Stanford Health Assessment Questionnaire - Functional Disability Index (HAQ) in Patient with Rheumatoid Arthritis (RA)
Szilasiová A., Macejová Ž., Nagyová I., Kovařová M., Bérešová A., Szilasiová J
II. interná klinika Lekárskej fakulty UPJŠ, Košice, Slovenská republika, prednosta doc. MUDr. Dušan Trejbal, CSc. Ústav sociálnej medicíny Lekárskej fakulty UPJŠ, Košice, Slovenská republika, prednostka MUDr. Mária Kovařová, CSc. Neurologická klinika Lekárskej fakulty UPJŠ, Košice, Slovenská republika, prednosta doc. MUDr. Eugen Eiben, CSc. Northen Centre for Healthcare Research, University of Groningen, Rada pre poradenstvo v sociálnej práci Košice, Slovenská republika |
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Summary:
Background: Functional disability is one of the most important consequences of RA in the
patient's daily life. The HAQ has been widely used in its self administered form for the assessment
of disability. A sensitive and valid instrument is needed for a Slovak population with RA. Objecti-
ve: To evaluate reliability and validity of the Slovak version of the HAQ in patients with RA and to
explore relationships between HAQ score and disease activity and to provide information concer-
ning utilization of this instrument in clinical practice. Methods: In preparing the Slovak version
of the HAQ careful attention has been paid to the translation, in terms of linguistic and conceptu-
al equivalence, in order to preserve the original purpose of the instrument. The wording of some
items required adaptation to the current activities of daily living and Slovak lifestyle. The sample
consisted of 160 RA-patients, out of which 135 were women and 25 were men. The inclusion
criteria were the following: age from 20 to 70 years at the onset of the study, diagnosis of RA
according to the ARA criteria. The exclusion criteria were the presence of another serious disease
or very disabling RA (stage IV of the Steinbrocker's classification). To analyze the data t-test, correlations, one-way analysis of variance (ANOVA), and principal component analysis (PCA)
available in the SPSS/PC+ statistical package were used. Results: The Cronbach's coefficient of
reliability alpha for the HAQ total scale was 0.94. The results of PCA showed that the 20 HAQ
items loaded on four components for which the eigen values were greater than 1, accounting for
70 % of overall interpersonal variability. Orthogonal varimax rotation of the principal compo-
nents provided factor loadings reflecting the eight dimensions within the HAQ. Validity of the
HAQ was examined further by means of known-groups technique. The HAQ was found to be
sensitive to differentiate between the Steinbrocker's functional capacity groups, as well as be-
tween males and females. Moreover, significant correlations (p < 0.01) were found between the
HAQ and the C-reactive protein, the ESR, the NHP-pain, the Ritchie articular index, the
Steinbrocker's functional capacity (r = 0.31 - 0.62) and disease duration (p < 0.05, r = 0.17). Conclu-
sion: The results of the current investigation provide support for reliability and construct validity
of the Slovak version of the HAQ in patients with RA. The HAQ has sufficient discriminant ability.
The index disability can be used as an criterion of severity of RA, as a criterion of effectiveness in
therapeutical trials for patient stratification of the Slovak population with RA.
Key words:
Reliability - Validity - Rheumatoid arhtritis - Disability - Stanford health assessment
questionnaire (HAQ)
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