Health-related quality of life in patients with inflammatory bowel disease measured with the short form-36: Psychometric assessments and a comparison with general population norms

Background: We compared health-related quality of life (HRQOL) in a population-based cohort of Norwegian patients with inflammatory bowel disease (IBD) with a normal reference population by means of the short form-36 (SF-36) questionnaire, including the effect of age, sex, educational status, and symptom severity and the psychometric properties of the questionnaire. Methods: The SF-36 was self-administered and was answered by the patients at the hospital at 2 occasions that were 6 months apart. Results: Five hundred fourteen patients with IBD were eligible for analysis: 348 with ulcerative colitis (UC) and 166 with Crohn's disease (CD). The comparison group consisted of 2323 Norwegian people. The dimension scores for SF-36 were significantly lower in 6 of 8 dimensions for patients with UC and in 7 of 8 dimensions for patients with CD than for the reference population. In both patients with UC and patients with CD, we found lower scores in elderly patients, which also was found in the background population. Women scored lower than men in all dimension scores. In both patients with UC and patients with CD, there was a statistically significant reduction in HRQOL score with increasing symptoms. The SF-36 has satisfactory reliability and discriminant ability for scores for all dimensions in both patients with UC and patients with CD. However, when measuring responsiveness, the figures were generally low. This finding, together with the high ceiling effects, may indicate that the SF-36 has limitations regarding detecting deterioration or improvement over time. Conclusion: We have shown that HRQOL in a Norwegian population-based cohort of patients with IBD, measured with the SF-36, is lower than that of a Norwegian reference population. In general, the SF-36 was found to have satisfactory psychometric properties in this IBD population.