AppendicitisCASARELAXNCT05002829
Restricted or Liberal Antibiotics After Appendectomy - Denver Health
A study testing Restricted Duration of SOC Antibiotic Use and Liberal Duration of SOC Antibiotic Use in people with Appendicitis, run by Denver Health and Hospital Authority at 1 site in United States.
Trial summary
The purpose of this study is to see if decreasing the amount of antibiotics after appendicitis surgery can decrease the risk of adverse effects associated with antibiotics while at the same time ensuring participant safety. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Appendicitis
- What is being tested?
- Restricted Duration of SOC Antibiotic Use and Liberal Duration of SOC Antibiotic Use
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 657 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Nov 2021to 16 Jul 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age ≥ 18 years
- Planned appendectomy (laparoscopic or open) for simple or complicated (perforated or gangrenous) appendicitis
- Working telephone number or reliable method to contact patient after hospital discharge
Who cannot join
- Unable to consent
- Pregnant Women
- Prisoners
- Immunocompromised as determined by clinical team, or patients actively receiving steroids, chemotherapy, or immunosuppressing medications (for example tacrolimus), or patients with active hematologic malignancy affecting the immune system, leukopenia, or end-stage AIDS
- Heart failure
- Allergy to bupivacaine
Show all 14Show fewer
- Unlikely to comply with treatment or follow-up
- Inpatient consultation for appendicitis
- Clinically suspected of sepsis based on Sepsis-3 definition
- Current use of antibiotics for other indications
- Uncontrolled hyperglycemia or Type 1 Diabetes
- Surgeon preference
- Patient preference
- Research team unavailable
Trial locations and contacts
1 site in 1 country.
United States1 site
Denver Health and Hospital Authority
Denver, Colorado, 80204-4507
About this study
Official title: Complex And Simple Appendicitis: REstrictive or Liberal Post-operative Antibiotic eXposure (CASA RELAX) Using Desirability of Outcome Ranking (DOOR) and Response Adjusted for Duration of Antibiotic Risk (RADAR): A Randomized Controlled Trial at Denver Health
The purpose of this study is to see if decreasing the amount of antibiotics after appendicitis surgery can decrease the risk of adverse effects associated with antibiotics while at the same time ensuring participant safety.
- Conditions
- Appendicitis
- Being tested
- Restricted Duration of SOC Antibiotic Use, Liberal Duration of SOC Antibiotic Use
- Keywords
- post-operative, antibiotics
- Medical subject headings
- Appendicitis
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Restricted Duration of SOC Antibiotic UseOther
Standard of Care Antibiotic use will be restricted to none or up to 24 hours of post-operative antibiotics.
Liberal Duration of SOC Antibiotic UseOther
Standard of Care Antibiotic use will be permitted for 24 hours or up to 4 days of post-operative antibiotics.
| Study group | Role | What they receive |
|---|---|---|
| Restricted Post-Operative Antibiotics Group | Experimental | Participants undergoing standard of care (SOC) with simple appendicitis will not receive post-operative antibiotics.
Participants undergoing standard of care with complicated (gangrenous or perforated) appendicitis will receive up to 24 hours of SOC post-operative antibiotics. Receives: Other: Restricted Duration of SOC Antibiotic Use |
| Liberal Post-Operative Antibiotics Group | Active comparator | Participants undergoing standard of care with simple appendicitis will receive 24 hours of post-operative SOC antibiotics
Participants undergoing standard of care with complicated (gangrenous or perforated) appendicitis will receive 4 days of post-operative SOC antibiotics. Receives: Other: Liberal Duration of SOC Antibiotic Use |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of participants with no antibiotic related adverse effects
As assessed by treating physician
Measured: Up to 40 days after appendicitis surgery
Incidence of Infectious/Antibiotic Complications
Infectious/antibiotic complication requiring antibiotic treatment only, Emergency Department visit, hospital readmission, percutaneous drainage, and operative intervention as assessed by treating physician.
Measured: Up to 30 days after appendicitis surgery
Number of participant deaths
As assessed by treating physician
Measured: Up to 30 days after appendicitis surgery
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Aug 2021
- Study start1 Nov 2021
- Primary completion16 Jul 2025
- Study completion16 Jul 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (6)Papers the sponsor has linked to this study.
- Other trials for AppendicitisStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 657 participants (actual)
Sponsor and investigators
- Lead sponsor
- Denver Health and Hospital Authority
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Daniel Yeh, Denver Health and Hospital Authority
- Investigators
- Daniel D Yeh, MD, MHPE, Principal investigator, Denver Health and Hospital Authority
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05002829
- Sponsor's protocol ID
- 20191238
- Acronym
- CASARELAX
- Status last verified
- Jun 2026
- First submitted
- 4 Aug 2021
- Last updated
- 30 Jun 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Sawyer RG, Claridge JA, Nathens AB, Rotstein OD, Duane TM, Evans HL, Cook CH, O'Neill PJ, Mazuski JE, Askari R, Wilson MA, Napolitano LM, Namias N, Miller PR, Dellinger EP, Watson CM, Coimbra R, Dent DL, Lowry SF, Cocanour CS, West MA, Banton KL, Cheadle WG, Lipsett PA, Guidry CA, Popovsky K; STOP-IT Trial Investigators. Trial of short-course antimicrobial therapy for intraabdominal infection. N Engl J Med. 2015 May 21;372(21):1996-2005. doi: 10.1056/NEJMoa1411162.
PubMed 25992746Yeh DD, Eid AI, Young KA, Wild J, Kaafarani HMA, Ray-Zack M, Kana'an T, Lawless R, Cralley AL, Crandall M; EAST Appendicitis Study Group. Multicenter Study of the Treatment of Appendicitis in America: Acute, Perforated, and Gangrenous (MUSTANG), an EAST Multicenter Study. Ann Surg. 2021 Mar 1;273(3):548-556. doi: 10.1097/SLA.0000000000003661.
PubMed 31663966Lawless RA, Cralley A, Qian S, Vasileiou G, Yeh DD; EAST Appendicitis Study Group. Antibiotics after Simple (Acute) Appendicitis are not Associated with Better Clinical Outcomes: A Post-Hoc Analysis of an EAST Multi-Center Study. Surg Infect (Larchmt). 2021 Jun;22(5):504-508. doi: 10.1089/sur.2019.348. Epub 2020 Sep 3.
PubMed 32897168Bou Zein Eddine S, Dodgion CM, Qian S, Trevino C, De Moya MA, Yeh DD; EAST Appendicitis Research Group. Complicated Appendicitis: Are Extended Antibiotics Necessary? A Post Hoc Analysis of the EAST Appendicitis "MUSTANG" Study. J Surg Res. 2020 Mar;247:508-513. doi: 10.1016/j.jss.2019.09.054. Epub 2019 Dec 4.
PubMed 31812337Evans SR, Rubin D, Follmann D, Pennello G, Huskins WC, Powers JH, Schoenfeld D, Chuang-Stein C, Cosgrove SE, Fowler VG Jr, Lautenbach E, Chambers HF. Desirability of Outcome Ranking (DOOR) and Response Adjusted for Duration of Antibiotic Risk (RADAR). Clin Infect Dis. 2015 Sep 1;61(5):800-6. doi: 10.1093/cid/civ495. Epub 2015 Jun 25.
PubMed 26113652Yeh DD, Hatton GE, Pedroza C, Pust G, Mantero A, Namias N, Kao LS. Complex And Simple Appendicitis: REstrictive or Liberal postoperative Antibiotic eXposure (CASA RELAX) using Desirability of Outcome Ranking (DOOR) and Response Adjusted for Duration of Antibiotic Risk (RADAR): study protocol for a randomized controlled trial. Trauma Surg Acute Care Open. 2022 Sep 16;7(1):e000931. doi: 10.1136/tsaco-2022-000931. eCollection 2022.
PubMed 36148315
Study at a glance
From the registry record, last updated by the sponsor on 30 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Complex And Simple Appendicitis: REstrictive or Liberal Post-operative Antibiotic eXposure (CASA RELAX) Using Desirability of Outcome Ranking (DOOR) and Response Adjusted for Duration of Antibiotic Risk (RADAR): A Randomized Controlled Trial at Denver Health
- ClinicalTrials.gov ID
- NCT05002829
- Acronym / sponsor ID
- CASARELAX / 20191238
- Conditions
- Appendicitis
- Keywords
- post-operative, antibiotics
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 657 participants (actual)
- Lead sponsor
- Denver Health and Hospital AuthorityUniversity, hospital or other
- Study start
- 1 Nov 2021 (actual)
- Primary completion
- 16 Jul 2025 (actual)
- Study completion
- 16 Jul 2025 (actual)
- First posted
- 12 Aug 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to see if decreasing the amount of antibiotics after appendicitis surgery can decrease the risk of adverse effects associated with antibiotics while at the same time ensuring participant safety.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Restricted Post-Operative Antibiotics Group | Experimental | Other: Restricted Duration of SOC Antibiotic UseParticipants undergoing standard of care (SOC) with simple appendicitis will not receive post-operative antibiotics. Participants undergoing standard of care with complicated (gangrenous or perforated) appendicitis will receive up to 24 hours of SOC post-operative antibiotics. |
| Liberal Post-Operative Antibiotics Group | Active comparator | Other: Liberal Duration of SOC Antibiotic UseParticipants undergoing standard of care with simple appendicitis will receive 24 hours of post-operative SOC antibiotics Participants undergoing standard of care with complicated (gangrenous or perforated) appendicitis will receive 4 days of post-operative SOC antibiotics. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Age ≥ 18 years
- Planned appendectomy (laparoscopic or open) for simple or complicated (perforated or gangrenous) appendicitis
- Working telephone number or reliable method to contact patient after hospital discharge
Key exclusion criteria (14 listed)
- Unable to consent
- Pregnant Women
- Prisoners
- Immunocompromised as determined by clinical team, or patients actively receiving steroids, chemotherapy, or immunosuppressing medications (for example tacrolimus), or patients with active hematologic malignancy affecting the immune system, leukopenia, or end-stage AIDS
- Heart failure
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Restricted Duration of SOC Antibiotic UseStandard of Care Antibiotic use will be restricted to none or up to 24 hours of post-operative antibiotics. | Other | Restricted Post-Operative Antibiotics Group |
| Liberal Duration of SOC Antibiotic UseStandard of Care Antibiotic use will be permitted for 24 hours or up to 4 days of post-operative antibiotics. | Other | Liberal Post-Operative Antibiotics Group |
Primary outcome
Number of participants with no antibiotic related adverse effects
Time frame: Up to 40 days after appendicitis surgery
As assessed by treating physician
Incidence of Infectious/Antibiotic Complications
Time frame: Up to 30 days after appendicitis surgery
Infectious/antibiotic complication requiring antibiotic treatment only, Emergency Department visit, hospital readmission, percutaneous drainage, and operative intervention as assessed by treating physician.
Number of participant deaths
Time frame: Up to 30 days after appendicitis surgery
As assessed by treating physician
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Jun 2026.
- Background: PubMed 25992746Sawyer RG, Claridge JA, Nathens AB, Rotstein OD, Duane TM, Evans HL, Cook CH, O'Neill PJ, Mazuski JE, Askari R, Wilson MA, Napolitano LM, Namias N, Miller PR, Dellinger EP, Watson CM, Coimbra R, Dent DL, Lowry SF, Cocanour CS, West MA, Banton KL, Cheadle WG, Lipsett PA, Guidry CA, Popovsky K; STOP-IT Trial Investigators. Trial of short-course antimicrobial therapy for intraabdominal infection. N Engl J Med. 2015 May 21;372(21):1996-2005. doi: 10.1056/NEJMoa1411162.
- Background: PubMed 31663966Yeh DD, Eid AI, Young KA, Wild J, Kaafarani HMA, Ray-Zack M, Kana'an T, Lawless R, Cralley AL, Crandall M; EAST Appendicitis Study Group. Multicenter Study of the Treatment of Appendicitis in America: Acute, Perforated, and Gangrenous (MUSTANG), an EAST Multicenter Study. Ann Surg. 2021 Mar 1;273(3):548-556. doi: 10.1097/SLA.0000000000003661.
- Background: PubMed 32897168Lawless RA, Cralley A, Qian S, Vasileiou G, Yeh DD; EAST Appendicitis Study Group. Antibiotics after Simple (Acute) Appendicitis are not Associated with Better Clinical Outcomes: A Post-Hoc Analysis of an EAST Multi-Center Study. Surg Infect (Larchmt). 2021 Jun;22(5):504-508. doi: 10.1089/sur.2019.348. Epub 2020 Sep 3.
- Background: PubMed 31812337Bou Zein Eddine S, Dodgion CM, Qian S, Trevino C, De Moya MA, Yeh DD; EAST Appendicitis Research Group. Complicated Appendicitis: Are Extended Antibiotics Necessary? A Post Hoc Analysis of the EAST Appendicitis "MUSTANG" Study. J Surg Res. 2020 Mar;247:508-513. doi: 10.1016/j.jss.2019.09.054. Epub 2019 Dec 4.
- Background: PubMed 26113652Evans SR, Rubin D, Follmann D, Pennello G, Huskins WC, Powers JH, Schoenfeld D, Chuang-Stein C, Cosgrove SE, Fowler VG Jr, Lautenbach E, Chambers HF. Desirability of Outcome Ranking (DOOR) and Response Adjusted for Duration of Antibiotic Risk (RADAR). Clin Infect Dis. 2015 Sep 1;61(5):800-6. doi: 10.1093/cid/civ495. Epub 2015 Jun 25.
- Derived from this study: PubMed 36148315Yeh DD, Hatton GE, Pedroza C, Pust G, Mantero A, Namias N, Kao LS. Complex And Simple Appendicitis: REstrictive or Liberal postoperative Antibiotic eXposure (CASA RELAX) using Desirability of Outcome Ranking (DOOR) and Response Adjusted for Duration of Antibiotic Risk (RADAR): study protocol for a randomized controlled trial. Trauma Surg Acute Care Open. 2022 Sep 16;7(1):e000931. doi: 10.1136/tsaco-2022-000931. eCollection 2022.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Daniel D Yeh, MD, MHPE principal investigator
Denver Health and Hospital Authority
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Restricted Duration of SOC Antibiotic Use and Liberal Duration of SOC Antibiotic Use in people with Appendicitis, run by Denver Health and Hospital Authority at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 30 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of participants with no antibiotic related adverse effects (time frame: Up to 40 days after appendicitis surgery). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05002829, which also lists 6 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Jun 2026.