[1]
Institute for Health Metrics and Evaluation (IHME). Global Burden of Disease Study 2023. United States Crohn's disease prevalence: ~319,000 (98.4 per 100,000; 95% CI: 83.3–116.4).
[2]
Nahon S et al. "Diagnostic delay in Crohn's disease: a population-based study from the EPIMAD registry."
Alimentary Pharmacology & Therapeutics, 2019;50(5):545–554. 47% initially diagnosed with IBS or functional bowel disorder before correct CD diagnosis.
[3]
Schoepfer AM et al. "Delay in Diagnosis of Crohn's Disease Is Associated with a Complicated Disease Course and Increased Operation Rate."
American Journal of Gastroenterology, 2013;108(11):1744–1753. Median diagnostic delay: 6.7 years (interquartile range 2.5–14.6).
[4]
Youssef N et al. "Work Productivity Impairment in Persons with Inflammatory Bowel Diseases: A Systematic Review and Meta-analysis."
Journal of Crohn's & Colitis, 2024;18(9):1486–1498. Crohn's patients: mean 26 sick days/year; 4.3 impaired work-hours/week; 1 in 3 report job loss.
[5]
Prefontaine E et al. "Azathioprine or 6-mercaptopurine for induction of remission in Crohn's disease."
Cochrane Database of Systematic Reviews, 2010, Issue 6. Risk of failure to achieve remission: 42% (RR 0.85, 95% CI 0.71–1.01); onset of effect requires 3–6 months.
[6]
Gisbert JP, Gomollón F. "Thiopurine-induced myelotoxicity in patients with inflammatory bowel disease: a systematic review."
American Journal of Gastroenterology, 2008;103(7):1783–1800. Serious adverse events (leukopenia, hepatotoxicity, pancreatitis, infection) leading to discontinuation: 9–17%.
[7]
Colombel JF et al. "Adalimumab for maintenance of clinical response and remission in patients with Crohn's disease: the CHARM trial."
Gastroenterology, 2007;132(1):52–65. Primary non-response (no response by week 4): ~33% of patients.
[8]
Gisbert JP et al. "Systematic Review and Meta-analysis: Loss of Response and Requirement for Dose Escalation of Anti-TNF Drugs in Crohn's Disease."
Inflammatory Bowel Diseases, 2022;28(11):1664–1676. Secondary loss of response to adalimumab: ~50% within 2 years; annual loss of response rate 13–15%.
[9]
Feagan BG et al. "Ustekinumab as Induction and Maintenance Therapy for Crohn's Disease."
New England Journal of Medicine, 2016;375(20):1946–1960. UNIFI trial: 48% failed to achieve clinical response at week 8 induction across bio-failure populations (response rate 52%, so non-response ~48%).
[10]
Bernstein CN et al. "Surgery for Inflammatory Bowel Diseases."
Diseases of the Colon & Rectum, 2012;55(4):398–406. Population-based data: 5-year cumulative surgery risk in biologic-refractory Crohn's disease approximately 39%; overall 10-year surgery rate ~70%.
[11]
Cosnes J et al. "Epidemiology and Natural History of Inflammatory Bowel Diseases."
Gastroenterology, 2011;140(6):1785–1794. Cumulative probability of intestinal resection in Crohn's disease: ~35% at 5 years, ~70% at 10 years.
[12]
De Cruz P et al. "Postoperative recurrence of luminal Crohn's disease: a systematic review."
Inflammatory Bowel Diseases, 2012;18(4):758–777. Endoscopic recurrence at anastomosis site: 65–90% by 12 months without prophylactic therapy. Clinical recurrence: ~40–50% at 5 years; re-operation: ~50% within 10 years.
[13]
Jess T et al. "Risk of colorectal and small bowel cancer in patients with Crohn's disease: a meta-analysis."
Alimentary Pharmacology & Therapeutics, 2005;21(9):1097–1105. SIR for small bowel cancer: 18.2 (95% CI 11.4–27.4); colorectal cancer SIR 2.5 (95% CI 1.3–4.6). Risk elevated 2–4× overall.
[14]
Targownik LE et al. "Similar risk of Depression and Anxiety following surgery or hospitalization for Crohn's disease and Ulcerative colitis."
American Journal of Gastroenterology, 2013;108(4):594–601. Female post-surgical depression aOR 1.77 (Crohn's). 67% of depressed post-surgical Crohn's patients had surgery before age 35.
[15]
Tinsley A et al. "Delays in Biologic Therapy Initiation for Crohn's Disease: Analysis of Healthcare Resource Utilization Prior to Initiation."
Digestive Diseases and Sciences, 2020;65(9):2696–2705. Mean 20–25 outpatient encounters in the 12 months preceding biologic initiation; 38% had ≥1 ED visit.
[16]
Park KT et al. "The Cost of Inflammatory Bowel Disease: An Initiative from the Crohn's & Colitis Foundation."
Inflammatory Bowel Diseases, 2020;26(1):1–10 (figures corroborated by Mehta F,
Am Health Drug Benefits, 2016;9(6):318–318). Commercial claims analyses consistently report total annual healthcare costs 3–6× higher for biologic-treated Crohn's patients compared with those managed on conventional therapy alone, driven overwhelmingly by drug acquisition cost rather than medical service use.