Establishing the Psychometric Properties of the ICOAP Questionnaire through Intra-Articular Treatment of...

Objectives. In this prospective study, we intend to establish the psychometric properties of ICOAP for its use in studies involving the Hellenic population. Methods. SF-36 Health Survey was used as a standard against ICOAP scores from a sample of 89 patients (mean age: 71.07, 69 females) with hip and knee OA pain who underwent 2 treatment cycles of 4 intra-articular injections of sodium hyaluronate, separated by a 12-week medication-free time interval. Both questionnaires were filled twice with no missing data during follow-up. Results. ROC analysis accomplished ICOAP's criterion-related validation. Wilcoxon Signed-Rank Test and paired samples t-test endorsed ICOAP's responsiveness along with Effect Size values, standard response mean, and Relative Efficiency. Comparisons between the areas under curves (AUC) on ROC plots established external responsiveness. Cronbach's-alpha value favored ICOAP's internal consistency. This, along with intraclass correlation, results in both advocated reliability and content validity. Interitem discrimination was demonstrated by the ease of completion of ICOAP as well as the degree of familiarity with it. These findings inaugurated construct validity in collaboration with Spearman's and One-Way ANOVA results. Conclusions. ICOAP is a valid, reliable, and responsive QoL instrument and suitable for studies of osteoarthritic joint pain in the Greek setting.