P221 Validity of the Self-administered Comorbidity Questionnaire in patients with Inflammatory Bowel Disease

Abstract

Abstract Background The International Consortium for Health Outcomes Measurement (ICHOM) has defined a standard set of outcome measures for inflammatory bowel disease (IBD) to capture effectiveness of care delivery processes by systematic collection of outcomes. However, several case-mix variables can confound the outcome measures and should be adjusted for before interpreting and comparing outcomes. To account for the impact of comorbidities, the self-assessed comorbidity questionnaire (SCQ), containing 36 questions on presence, treatment and limitation of thirteen diseases, was selected by ICHOM. As the SCQ has been validated for other diseases, but not for IBD, we aimed to assess the validity of the SCQ for measuring comorbidities in a population of IBD patients. Methods Data in this study was extracted from a prospective study evaluating quality of care of IBD patients treated with a biologic or new small molecule. We assessed criterion validity by comparing patient-reported and clinician-reported presence (as noted in the electronic health record) of the thirteen diseases of the SCQ using Cohen’s kappa. Construct validity was assessed by evaluating the Spearman correlation coefficient between the SCQ and the Charlson Comorbidity Index (CCI), clinician-reported SCQ, quality of life (EQ-5D-5L), IBD-related healthcare and productivity costs and prevalence of disability. We assessed responsiveness by measuring the correlation between changes in the SCQ and changes in healthcare costs, productivity costs and quality of life after 15 months. Results A total of 642 patients were included. Median age was 49, 56% were female and 60% had Crohn’s disease. Median SCQ at baseline was 1.75 (IQR: 0.01 – 4.00) and increased to 2 (IQR: 0.26-4.00) after 15 months of follow-up. Fair agreement was found for most comorbidities, but agreement was poor for back pain, arthritis, blood diseases, stomach diseases, kidney diseases and depression (Table 1). Significant correlations were found between the SCQ and CCI, clinician-reported SCQ, quality of life, prevalence of disability and productivity costs, but not with healthcare costs (Table 2). A change in the SCQ after 15 months was negatively correlated with a change in quality of life, but not with a change in healthcare or productivity costs. Conclusion The SCQ seems a useful tool to adjust for case-mix for health-related quality of life in IBD patients, but does not relate to IBD-attributable healthcare or productivity costs. The SCQ does not always agree with the electronic health record, which may be due to inadequate capture of comorbidities in the electronic health record or because patients may confuse comorbidities and complications of IBD.