Background/Purpose:

To develop and validate a specific questionnaire to measure health-related quality of life (HRQoL) in adults with psoriasis arthritis (PA) for use in clinical studies and clinical practice .

Methods:

Item selection was generated through an extensive literature review, the experience of patients with PA, and discussion with  PA expert rheumatologists. Item reduction was performed using clinimetric and psychometric approaches after administration of the item selection to 66 PA patients. The resulting questionnaire, named VITACORA, consists of 19 items. The factorial analysis explained its unidimensionality and an overall HRQoL score. Internal consistency, test–retest (10 days) reliability, sensitivity analysis, known groups and convergent validity were tested in a prospective, observational, multicenter study conducted in 10 Spanish hospitals with 323 subjects, who also completed the Euro-QoL 5 Dimensional questionnaire (EQ-5D) and a health status transition item. Three study groups were defined: group A (n=209) comprised PA patients ; group B (n=71) comprised patients with arthritis no psoriasis; and group C (n=43) comprised healthy people. All subjects attended baseline visit and group A patients also test-retest and final visits (10 days and 6 months later, respectively).

Results:

VITACORA questionnaire was considered easy or very easy to answer by 94.7% of PA patients. Missing response rate was less than 3.8% in all questionnaire items. Floor and ceiling effects were less than 2% for the overall score. Cronbach’s alpha values and intraclass correlation coefficient values for the overall score exceeded 0.90. Statistically significant differences (p<0.001) were observed on the overall score between groups: subjects from group C (healthy people, mean overall score 93.7, SD 9.1) had a better HRQoL, following from group B (patients with arthritis no psoriasis, mean overall score 69.2, SD 24.8), and finally group A (PA patients, mean overall score 56.2, SD 24.8) had the worse HRQoL. As expected, the VITACORA scores showed significant correlations (p<0.001) to EQ-5D and to perceived health state scores. Likewise, lower correlations to clinical variables were found. At follow-up, the VITACORA scores showed significant correlations to health state change reported by PA patients and investigators. Effect sizes for the global score changes between two study visits (baseline and 6 months later) among PA patients ranged from 0.20 to 0.80, reporting an improvement in health status. The minimum important difference was established as an 8-point change in the global VITACORA score.

Conclusion:

This new, developed instrument to measure HRQoL in PA patients has shown good reliability, validity, and sensitivity to change. It has also proved easy to use and administer in daily clinical practice and future research projects.

---

« Back to 2012 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/developmen-and-validation-of-a-new-instrument-to-asess-health-related-quality-of-life-in-psoriasis-arthritis-the-vitacora-questionnaire/