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Comparing surgery and medical management for diverticulitis

Comparison of Surgery and Medicine on the Impact of Diverticulitis (COSMID) Trial

NA · University of Washington · NCT04095663

This study is testing whether surgery or the best medical treatment helps people with diverticulitis feel better and improve their quality of life.

Quick facts

PhaseNA
Study typeInterventional
Enrollment250 (estimated)
Ages18 Years and up
SexAll
SponsorUniversity of Washington (other)
Drugs / interventionschemotherapy, radiation
Locations28 sites (Los Angeles, California and 27 other locations)
Trial IDNCT04095663 on ClinicalTrials.gov

What this trial studies

The COSMID trial is a randomized trial that compares elective colectomy with best medical management for patients suffering from quality of life-limiting diverticular disease. It aims to determine whether surgical intervention leads to better patient-reported outcomes compared to non-invasive medical treatments. Additionally, an observational cohort will be included for patients who prefer not to be randomized but are willing to share their outcomes. The study seeks to address the evolving understanding of diverticulitis management and the effectiveness of surgical versus medical approaches.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 and older with a history of recurrent uncomplicated diverticulitis who are experiencing quality of life issues related to their condition.

Not a fit: Patients who have previously undergone surgery for diverticulitis or those with current complications such as fistulas or strictures may not benefit from this study.

Why it matters

Potential benefit: If successful, this trial could provide clearer guidance on the most effective treatment options for patients with diverticulitis, potentially improving their quality of life.

How similar studies have performed: Other studies have explored surgical versus medical management for diverticulitis, but the COSMID trial aims to provide more definitive evidence in a contemporary context.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

1. Adults ≥18 years
2. At least one episode of diverticulitis confirmed by CT scan (or pending confirmation) and a colonoscopy (completed or scheduled) to rule out or screen for other colon pathology concordant with screening guidelines; AND A. History of recurrent uncomplicated diverticulitis without current symptoms (AUD in remission); OR B. Persistent signs, symptoms, and concerns related to diverticular disease ≥3 months after recovery from an episode of AUD (e.g., excluding irritable bowel syndrome and other conditions in coordination with gastroenterologist)

Exclusion Criteria:

1. Unable or unwilling to return or be contacted for and/or complete research surveys;
2. Currently incarcerated in a detention facility or in police custody (patients wearing a monitoring device can be enrolled) at baseline/screening;
3. Previous operation for diverticulitis
4. Current diagnosis or previous endoscopic or surgical interventions for fistula or stricture or current significant bleeding related to diverticular disease.
5. Right-sided diverticulitis
6. Comorbid or prior surgical conditions that contraindicate elective surgery (e.g., liver failure, renal failure, malignancy, "frozen abdomen")
7. Actively undergoing chemotherapy or radiation for malignancy
8. Immunodeficiency (e.g., absolute neutrophil count \<500/mm3, chronic immunosuppressive drugs (e.g., oral corticosteroids, anti-TNF agents), or known AIDS \[i.e., recent CD4 count \<200 \] assessed by patient history);
9. Taking prescription medication to treat active inflammatory bowel disease (e.g., Crohn's, ulcerative colitis);
10. Taking prescription medication for irritable bowel syndrome;
11. Pregnant or expectation of becoming pregnant in the 30 days following baseline/screening;
12. Prior enrollment in the study or other investigational drug or vaccine while on study treatment;
13. Abdominal/pelvic surgery in the past month

Where this trial is running

Los Angeles, California and 27 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Diverticulitis

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.