Evaluation of Reliability and validity of SF-36 in patients with Graves disease

Abstract

Objective To evaluate the reliability and validity of SF-36 (36-item Short Form Health Survey) in patients with Graves disease. Methods 113 patients with Graves disease were assessed using SF-36,20patients were reassessed randomly after 2 weeks, and the data was used to analyze reliability and validity. Results The cronbach' s α coefficient of internal consistency was 0.775. Cronbach' s α coefficient of 8 domains ranged from 0.571 to 0.868; the Spearman-Brown coefficient which assessed split-half reliability was 0.946; two weeks later 20 patients were choosen at random to be assessed again, the Pearson correlation coefficient of testretest reliability for the overall questionnair were 0.87. Construct validity were examined, and factor analysis showed two common factors which accounted for 59.71% of total variance were extracted. In criterion validity,the correlation coefficient of self-rated health and the total scores in the scale table was 0.726. Conclusion SF-36 has good reliability and validity and is useful for measurement and assessment of patients with Graves disease. Key words: SF-36; Graves disease; Quality of life; Reliability; Validity