Testtheoretische Überprüfung der deutschen Version des Intermittent and Constant Osteoarthritis Pain Score (ICOAP) – ein Fragebogen zur Schmerzerfassung bei Patienten mit Gonarthrose

Zusammenfassung

Studienziel: Das Ziel dieser Studie war die test-theoretische Absicherung der deutschen Version des Intermittent and Constant Osteoarthritis Pain Score (ICOAP) bei Patienten mit fortgeschrittener Gonarthrose. Methode: Die Reliabilität (Test-Retest-Reliabilität; interne Konsistenz), die Validität, die Sensitivität, die Praktikabilität und die Akzeptanz dieses Fragebogens wurden an 120 Patienten mit fortgeschrittener Gonarthrose überprüft. Ergebnisse: Die Test-Retest-Korrelation des Fragebogens war sowohl für die Subskalen als auch den Summenscore ausreichend hoch (r = 0,57–0,67). Auch zeigten die Subskalen eine hohe Homogenität. Der Vergleich mit den Schmerzskalen des WOMAC-Scores sowie des KOOS erbrachte eine hohe Übereinstimmung. Die Überprüfung der Sensitivität des Fragebogens zeigte einen signifikanten Rückgang der Schmerzen im Verlauf von 3 Monaten nach Implantation einer Knieendoprothese. Die Praktikabilität des Fragebogens ist gegeben, seine Akzeptanz war bei den Patienten sehr hoch. Schlussfolgerung: Mit der deutschsprachigen Version des ICOAP steht ein Instrument zur Erfassung von permanentem sowie wiederkehrendem Schmerz bei Patienten mit fortgeschrittener Gonarthrose zur Verfügung. Die Testkriterien haben eine gute Validität, Reliabilität, Praktikabilität und Akzeptanz gezeigt.

Abstract

Purpose of Study: The purpose of this investigation was to test the German version of the intermittent and constant osteoarthritis pain score (ICOAP) in patients with advanced knee osteoarthritis. The ICOAP measures pain with 12 items divided in the two subscales “pain which comes and goes” and “permanent pain”. Methods: The reliability, the validity, the sensitivity to change, the practicability and the acceptance of this questionnaire were investigated in 120 patients with advanced knee osteoarthritis necessitating a total knee replacement. Retest reliability was determined in a subsample of 29 patients prior to hospital admission. Convergent construct validity was assessed by comparing the results of the ICOAP subscales and the overall score to the pain scales of the Western Ontario and McMasters University osteoarthrosis score (WOMAC) and the knee-injury and osteoarthrosis outcome score (KOOS). Sensitivity to change was determined by comparing the results of the ICOAP prior to admission with those assessed at discharge from hospital as well as 3 months after knee replacement surgery. To quantify the strength of associations between the ICOAP scales and the measures of validity as well as to test its reliability the Spearman correlation coefficient was calculated with an absolute value of “r” indicating the strength of a relationship. Sensitivity to change was assessed with an analysis of variance of the score results at the three different times of assessment. A p value of < 0.5 was regarded to be significant. Results: The reliability of this questionnaire was high, retest reliability ranged between r = 0.57–0.67, for the overall score as well as for the subscales. As a further criterion of reliability the internal consistency of the questionnaire was high as well, with r = 0.81–0.9. In comparison to the WOMAC pain scale, there was a concordance with r = 0.67 (overall score) and r = 0.68 (subscales). The pain scale of the KOOS correlated highly to the ICOAP scales. It ranged between r = 0.64 and r = 0.91. The review of sensitivity to change of this questionnaire showed a significant (p < 0.5) decrease of pain within three months after implantation of a total knee arthroplasty for the overall score as well as for both subscales. The median significantly decreased from 30.37 to 12.93 % for the overall score and from 16.77 to 7.07 or, respectively, 13.59 to 5.86 for the subscales. Practicability is given and the acceptancy in patients was high, with no drop-outs during this study. Conclusion: With the validated German version of the ICOAP a questionnaire is available now which accurately measures pain in patients with advanced knee osteoarthritis.

Schlüsselwörter

intermittent and constant osteoarthritis Pain score (ICOAP) - Deutsche Version - Validität - Relibilität - Knie - Schmerzen

Key words

intermittent and constant osteoarthritis pain score (ICOAP) - German version - validity - reliability - knee - pain

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