Validierung von Lebensqualitäts-Assessments bei chronisch-obstruktiven Atemwegserkrankungen

Abstract

The St. George respiratory questionnaire (SGRQ) is a measure of health related quality of life for Chronic Obstructive Pulmonary disease (COPD) and asthma. Internationally there is a large body of evidence concerning its validity. The German version of the Saint George's Respiratory Questionnaire (SGRQ) has been used in numerous clinical studies since 1999. However a qualitative assessment and validation of the German version is missing.This work assesses the usability of the SGRQ concerning the indices and axioms of the Classical Test Theory (CTT). After an introduction to classical test theory, item (item difficulty) and scale (reliability, corrected item total correlations) analysis are performed and discussed. Criterion validity and aspects of the construct validity are analyzed concerning external health related measures (SF-36, SCL-90-R, EuroQOL), physiological measures (Forced Vital Capacity, FEV1, FEV1/Vc) and statistical comparisons between COPD and asthma patients. Based on data of 429 patients the results of this study show a satisfactory reliability and validity of the German SGRQ; but also of lack of CTT compatibility in parts.