The Disease Severity Index for Inflammatory Bowel Disease Is a Valid Instrument that Predicts Complicated Disease

Akhilesh Swaminathan; James M Fulforth; Chris M Frampton; Grace M Borichevsky; Thomas C Mules; Kate Kilpatrick; Myriam Choukour; Peter Fields; Resham Ramkissoon; Emily Helms; Stephen B Hanauer; Rupert W Leong; Laurent Peyrin-Biroulet; Corey A Siegel; Richard B Gearry

doi:10.1093/ibd/izad294

The Disease Severity Index for Inflammatory Bowel Disease Is a Valid Instrument that Predicts Complicated Disease

Inflamm Bowel Dis. 2023 Dec 22:izad294. doi: 10.1093/ibd/izad294. Online ahead of print.

Authors

Akhilesh Swaminathan^{1

2}, James M Fulforth³, Chris M Frampton¹, Grace M Borichevsky¹, Thomas C Mules^{1

2}, Kate Kilpatrick², Myriam Choukour⁴, Peter Fields⁵, Resham Ramkissoon⁶, Emily Helms⁷, Stephen B Hanauer⁸, Rupert W Leong⁷, Laurent Peyrin-Biroulet^{9

10

11

12

13

14}, Corey A Siegel¹⁵, Richard B Gearry^{1

2}

Affiliations

¹ Department of Medicine, University of Otago, Christchurch, New Zealand.
² Department of Gastroenterology, Christchurch Hospital, New Zealand.
³ Department of Gastroenterology, Waikato Hospital, Hamilton, New Zealand.
⁴ Centre Hospitalier Régional Universitaire (CHRU) Nancy, Délégation à la Recherche Clinique et à l'Innovation, Plateforme Maladies Inflammatoires Chroniques de l'Intestin (MICI), Vandoeuvre-lès-Nancy, France.
⁵ Division of Gastroenterology and Hepatology, School of Medicine & Dentistry, University of Rochester, Rochester, NY, USA.
⁶ Department of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA.
⁷ Department of Gastroenterology, Concord Hospital, Sydney, Australia.
⁸ Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
⁹ Deartment of Gastroenterology, Nancy University Hospital, F-54500 Vandoeuvre-les-Nancy, France.
¹⁰ INSERM, NGERE, University of Lorraine, F-54000 Nancy, France.
¹¹ INFINY Institute, Nancy University Hospital, F-54500 Vandoeuvre-les-Nancy, France.
¹² FHU-CURE, Nancy University Hospital, F-54500 Vandoeuvre-les-Nancy, France.
¹³ Groupe Hospitalier privé Ambroise Paré-Hartmann, Paris IBD Center, 92200 Neuilly sur Seine, France.
¹⁴ Division of Gastroenterology and Hepatology, McGill University Health Centre, Montreal, Quebec, Canada.
¹⁵ Section of Gastroenterology and Hepatology, Dartmouth Hitchcock Medical Center, LebanonNew Hampshire, USA.

PMID: 38134391
DOI: 10.1093/ibd/izad294

Abstract

Background: The disease severity index (DSI) for inflammatory bowel disease (IBD) combines measures of disease phenotype, inflammatory activity, and patient-reported outcomes. We aimed to validate the DSI and assess its utility in predicting a complicated IBD course.

Methods: A multicenter cohort of adults with IBD was recruited. Intraclass correlation coefficients (ICCs) and weighted Kappa assessed inter-rater reliability. Cronbach's alpha measured internal consistency of DSI items. Spearman's rank correlations compared the DSI with endoscopic indices, symptom indices, quality of life, and disability. A subgroup was followed for 24 months to assess for a complicated IBD course. Area under the receiver operating characteristics curve (AUROC) and multivariable logistic regression assessed the utility of the DSI in predicting disease progression.

Results: Three hundred and sixty-nine participants were included (Crohn's disease [CD], n = 230; female, n = 194; mean age, 46 years [SD, 15]; median disease duration, 11 years [interquartile range, 5-21]), of which 171 (CD, n = 99; ulcerative colitis [UC], n = 72) were followed prospectively. The DSI showed inter-rater reliability for CD (ICC 0.93, n = 65) and UC (ICC 0.97, n = 33). The DSI items demonstrated inter-rater agreement (Kappa > 0.4) and internal consistency (CD, α > 0.59; UC, α > 0.75). The DSI was significantly associated with endoscopic activity (CDn=141, r = 0.65, P < .001; UCn=105, r = 0.80, P < .001), symptoms (CDn=159, r = 0.69, P < .001; UCn=132, r = 0.58, P < .001), quality of life (CDn=198, r = -0.59, P < .001; UCn=128, r = -0.68, P < .001), and disability (CDn=83, r = -0.67, P < .001; UCn=52, r = -0.74, P < .001). A DSI of 23 best predicted a complicated IBD course (AUROC = 0.82, P < .001) and was associated with this end point on multivariable analyses (aOR, 9.20; 95% confidence interval, 3.32-25.49).

Conclusions: The DSI reliably encapsulates factors contributing to disease severity and accurately prognosticates the longitudinal IBD course.

Keywords: inflammatory bowel disease; outcomes research; symptom score or index.

Plain language summary

This study shows that the disease severity index (DSI) for inflammatory bowel disease (IBD) is a valid and reliable instrument encapsulating the disease phenotype, disease activity, and impact of the disease on the patient; and it accurately predicts for incident disease complications.