Frequency of IBD Flares
The frequency of IBD flares varies widely among patients, with approximately 28% of patients experiencing flares at least weekly and an additional 25% experiencing flares at least monthly, though many patients have less frequent flares occurring every few months to annually. 1
Patient-Reported Flare Frequency
The most robust patient-reported data comes from a national internet-based survey of 505 ulcerative colitis patients, which revealed:
- 27.9% reported ≥1 flare per week 1
- 25.1% reported ≥1 flare per month 1
- Most flares (76.5%) lasted ≤7 days 1
- 51.9% of flares were classified as moderate in severity 1
Importantly, among those reporting ≥1 flare per week, 30.5% still characterized their overall disease severity as mild, highlighting the disconnect between flare frequency and perceived disease control 1.
Clinical Context and Natural History
IBD follows a relapsing-remitting course with flares occurring unpredictably and randomly for most patients. 2 The natural history is characterized by alternating periods of remission and relapse, but no single pattern applies universally 2.
Post-Surgical Recurrence Rates
For patients who undergo intestinal resection for Crohn's disease:
- Endoscopic recurrence occurs in 65-90% within 12 months without treatment 3
- 80-100% show endoscopic recurrence within 3 years post-operatively 3
- Clinical recurrence risk is 28.0% overall, with 5-year and 10-year median cumulative rates of 23.5% 3
Monitoring Implications
Serial fecal calprotectin monitoring at 3-6 month intervals facilitates early recognition of impending disease flares in patients with mild symptoms or those in apparent remission. 4 This is particularly important because:
- Patients are typically seen only every 3-6 months in outpatient clinics, meaning flares between visits often go undetected 5
- Even after achieving endoscopic remission, only 29% and 41% of UC patients reported normal stool frequency at 8 and 52 weeks respectively 4
- Up to 27% of UC patients with both endoscopic and histologic healing continue to have increased stool frequency 4
Critical Pitfalls to Avoid
Do not assume that controlled disease means no flares will occur - 76.6% of survey respondents characterized their disease as controlled, yet over half still experienced flares at least monthly 1. This emphasizes that "controlled" IBD does not equate to flare-free disease.
Do not rely solely on patient perception of disease control - there is poor correlation between clinical and endoscopic indices of severity during acute flares in both ulcerative colitis and Crohn's disease 3.
Screen for C. difficile infection at every disease flare, as CDI occurs in 28.8% of IBD patients experiencing flares versus only 5.6% in inactive IBD 3. Superimposed infection is a common trigger that alters management 3.
Extraintestinal Manifestations
Some extraintestinal manifestations occur independent of intestinal disease flares, including anterior uveitis, ankylosing spondylitis, and primary sclerosing cholangitis 6. In contrast, peripheral arthritis, oral aphthous ulcers, episcleritis, and erythema nodosum typically correlate with active intestinal inflammation 6.