TY - JOUR
T1 - Aspects of validity of the self-administered comorbidity questionnaire in patients with ankylosing spondylitis
AU - Stolwijk, Carmen
AU - van Tubergen, Astrid
AU - Ramiro, Sofia
AU - Essers, Ivette
AU - Blaauw, Marc
AU - van der Heijde, Désirée
AU - Landewé, Robert
AU - van den Bosch, Filip
AU - Dougados, Maxime
AU - Boonen, Annelies
PY - 2014
Y1 - 2014
N2 - Objectives. To evaluate criterion and construct validity of the self-administered comorbidity questionnaire (SCQ) in patients with AS. Methods. The SCQ and indices of disease activity, physical function, health-related quality of life (HRQoL) and work disability were administered to 98 patients with AS. Criterion validity was assessed by the agreement between the SCQ answers and comorbidities identified in medical records. Construct validity was assessed by correlating the SCQ with the Charlson index and Michaud-Wolfe index; by correlating the SCQ with demographics, physical function, HRQoL and AS-related disease activity; and by exploring the contribution of comorbidity to these outcomes while adjusting for clinical-demographic characteristics. Furthermore, a modified version of the SCQ (mSCQ) was evaluated for the same aspects of validity, after removing rheumatic conditions. Results. Agreement was moderate to perfect for most conditions (kappa 0.47-1.00), except for ulcer disease, depression and OA (kappa 0.14-0.15). The correlation between the SCQ and Charlson and Michaud-Wolfe indices was 0.24 and 0.39 respectively, and between the mSCQ and both indices 0.36 and 0.53. Both SCQ and mSCQ correlated weakly to moderately with age, physical function and HRQoL (0.24-0.45). The SCQ also correlated weakly with disease activity (0.27) while the mSCQ did not (0.17). In multivariable analysis, both SCQ and mSCQ contributed independently to physical function, HRQoL and work disability, while the Michaud-Wolfe and Charlson indices did not. Conclusion. The SCQ is a promising instrument to determine comorbidities and to understand the impact on health outcomes in patients with AS. Excluding rheumatic conditions from the SCQ (mSCQ) improved validity
AB - Objectives. To evaluate criterion and construct validity of the self-administered comorbidity questionnaire (SCQ) in patients with AS. Methods. The SCQ and indices of disease activity, physical function, health-related quality of life (HRQoL) and work disability were administered to 98 patients with AS. Criterion validity was assessed by the agreement between the SCQ answers and comorbidities identified in medical records. Construct validity was assessed by correlating the SCQ with the Charlson index and Michaud-Wolfe index; by correlating the SCQ with demographics, physical function, HRQoL and AS-related disease activity; and by exploring the contribution of comorbidity to these outcomes while adjusting for clinical-demographic characteristics. Furthermore, a modified version of the SCQ (mSCQ) was evaluated for the same aspects of validity, after removing rheumatic conditions. Results. Agreement was moderate to perfect for most conditions (kappa 0.47-1.00), except for ulcer disease, depression and OA (kappa 0.14-0.15). The correlation between the SCQ and Charlson and Michaud-Wolfe indices was 0.24 and 0.39 respectively, and between the mSCQ and both indices 0.36 and 0.53. Both SCQ and mSCQ correlated weakly to moderately with age, physical function and HRQoL (0.24-0.45). The SCQ also correlated weakly with disease activity (0.27) while the mSCQ did not (0.17). In multivariable analysis, both SCQ and mSCQ contributed independently to physical function, HRQoL and work disability, while the Michaud-Wolfe and Charlson indices did not. Conclusion. The SCQ is a promising instrument to determine comorbidities and to understand the impact on health outcomes in patients with AS. Excluding rheumatic conditions from the SCQ (mSCQ) improved validity
U2 - https://doi.org/10.1093/rheumatology/ket354
DO - https://doi.org/10.1093/rheumatology/ket354
M3 - Article
C2 - 24249034
SN - 1462-0324
VL - 53
SP - 1054
EP - 1064
JO - Rheumatology (Oxford, England)
JF - Rheumatology (Oxford, England)
IS - 6
ER -