Can Coffee/Caffeine Improve Post-Operative Gastrointestinal Recovery

January 8, 2026 updated by: Dr. Paul Karanicolas, Sunnybrook Health Sciences Centre

Can Coffee/Caffeine Improve Post-Operative Gastrointestinal Recovery? A Vanguard Randomized Controlled Trial

Disruption of the normal gastrointestinal (GI) motility is a well-known consequence of major surgery. The pathophysiology behind this phenomenon is not fully understood but involves the autonomic nervous system as well as a systemic stress response to surgery. A number of factors interfere with GI motor activity, such as the direct manipulation of intestines during surgery and the use of opioid analgesia. Post-operative ileus (POI) refers to a delay in regaining GI motility beyond the anticipated normal duration of time. Signs and symptoms include nausea, vomiting, abdominal distention, the absence of flatus or stool in the preceding 24 hours, and/or an inability to tolerate oral intake. The incidence of POI in abdominal surgery is estimated to be approximately 10%-30%. Beyond increased patient discomfort and distress, the development of POI is associated with increased healthcare costs.

Coffee is a popular beverage: two thirds of Canadians are coffee drinkers, averaging approximately 3.2 cups per day. Coffee is composed of hundreds of chemicals, many with demonstrated pharmacologic effects. The most well-known of these compounds is caffeine, known to exert a stimulatory effect on the cardiovascular and nervous system. A recent systematic review of 7 randomized controlled trials (N=606 colorectal and gynecology surgical patients) determined that the consumption of coffee reduced the time of several measures of GI recovery, such as time to tolerance of food, without any increased rate of complications or adverse events although overall, the evidence was graded as low to moderate certainty, and further confirmatory studies are needed. In this trial, patients aged 18 years or higher who undergo laparoscopic or open abdominal surgery, with an estimated length of stay > 24 hours will be randomized to receive approximately one cup of either coffee, decaffeinated coffee, or warm water, three times daily. This trial will be conducted under the IMPACTS (Innovative, Multicentre, Patient-centred Approach to Clinical Trials in Surgery) program umbrella and will follow IMPACTS methodology. For the Vanguard trial, the aim is to determine the feasibility of conducting a definitive trial. Future outcomes of interest include: time to first flatus, time to first bowel movement, placement of an NG tube, length of stay in hospital, 30-day mortality, and 30-day postoperative complications.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Background/rationale: The development of POI is a common complication of surgery that is detrimental to patient well-being and ultimately leads to significant healthcare costs. Coffee is a popular drink among Canadians and appears to exert a positive effect on GI motility. This beverage may provide an inexpensive, easily administered and well-tolerated intervention to accelerate post-operative GI recovery, and thus reduce POI. The current literature, while promising, is insufficient and merits further investigation in the form of a high-quality randomized controlled trial.

Objectives: Before embarking on a definitive RCT, this pilot trial has five specific feasibility objectives:

  1. To assess our ability to accrue patients using the IMPACTS Program platform, at multiple institutions, over the course of one year.
  2. To assess our ability to adaptively randomize patients and deliver the randomized assignment using the IMPACTS Program platform, over the course of one year.
  3. To assess our ability to collect complete data directly from participants (patients and clinicians) on time to first flatus and time to first bowel movement over the course of one year.
  4. To examine our ability to carry out data linkages using the IMPACTS Program platform over the course of one year.
  5. To estimate the change in time to first flatus to inform the sample size calculation for the definitive trial.

Study design: This is a multicentre, pragmatic, 3-arm parallel group Vanguard feasibility randomized controlled trial. Patients will be randomly assigned to consume coffee, decaffeinated coffee, or warm water. If feasibility is demonstrated during the pilot trial, we will plan to conduct a definitive trial. If there are only minimal changes to the protocol, we will include data from the pilot phase into the definitive trial analysis (i.e. a Vanguard design).

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
174

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Ontario
      • North York, Ontario, Canada, M2K 1E1
        • North York General Hospital
      • Ottawa, Ontario, Canada, K1H 8L6
        • The Ottawa Hospital
      • Toronto, Ontario, Canada, M4N 3M5
        • Sunnybrook Health Sciences Centre

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

14 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age ≥ 18 years
  • Planned elective laparoscopic or open abdominal surgery
  • Patient is scheduled to remain in hospital for at least one night, post-operatively

Exclusion Criteria:

  • Known intolerance to coffee or caffeine
  • Unwilling to stop current caffeine consumption (coffee or tea) during trial

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Coffee
Caffeinated coffee beverage
Other: Coffee
Once the surgical team deems it appropriate to begin a clear liquid diet (in the post-operative period), approximately one cup of coffee will be provided to the patient three times daily. Additives such as cream, milk, sweetener and sugar, will be permitted. The intervention(s) will continue until a change is required as per the treating team or until hospital discharge. Patients will be asked to avoid any additional caffeine intake, such as tea, for the duration of the trial. If a patient receives an NG tube or is placed NPO by the treating team, the intervention will be halted and restarted once a clear liquid diet is restarted. All other aspects of the patients' care will be at the discretion of the treating team as per their standard practices.
Active Comparator: Decaffeinated coffee
Decaffeinated coffee beverage
Other: Decaffeinated Coffee
Once the surgical team deems it appropriate to begin a clear liquid diet (in the post-operative period), approximately one cup of decaffeinated coffee will be provided to the patient three times daily. Additives such as cream, milk, sweetener and sugar, will be permitted. The intervention(s) will continue until a change is required as per the treating team or until hospital discharge. Patients will be asked to avoid any additional caffeine intake, such as tea, for the duration of the trial. If a patient receives an NG tube or is placed NPO by the treating team, the intervention will be halted and restarted once a clear liquid diet is restarted. All other aspects of the patients' care will be at the discretion of the treating team as per their standard practices.
Placebo Comparator: Warm water
Warm water beverage
Other: Warm water
Once the surgical team deems it appropriate to begin a clear liquid diet (in the post-operative period), approximately one cup of warm water will be provided to the patient three times daily. Additives such as cream, milk, sweetener and sugar, will be permitted. The intervention(s) will continue until a change is required as per the treating team or until hospital discharge. Patients will be asked to avoid any additional caffeine intake, such as tea, for the duration of the trial. If a patient receives an NG tube or is placed NPO by the treating team, the intervention will be halted and restarted once a clear liquid diet is restarted. All other aspects of the patients' care will be at the discretion of the treating team as per their standard practices.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Assessment of accrual
Time Frame: 1 year
Average number of patients enrolled per month across the 3 sites for the trial: feasible if 10 or more
1 year
Ability to deliver intervention patient is randomized to receive
Time Frame: 1 year
Feasible if > 90% of patients receive the correct intervention
1 year
Ability to collect complete data for patient-reported outcomes
Time Frame: 1 year
Feasible if > 80% of data is collected
1 year
Ability to link data from patient-reported outcome measures with Institute for Clinical/Evaluative Sciences and National Surgical Quality Improvement Program datasets
Time Frame: 1 year
Feasible if linkage is possible in > 90% of patients
1 year
Measurement of baseline data
Time Frame: 1 year
  1. Median number of hours until flatus in control group
  2. Median number of hours until flatus in coffee and decaffeinated coffee groups
1 year

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Sunnybrook Health Sciences Centre

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Paul Karanicolas, MD PhD, Sunnybrook Health Sciences Centre

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
October 5, 2021

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
July 30, 2022

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
August 21, 2022

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
September 8, 2020

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 8, 2020

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 14, 2020

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
January 12, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 8, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • CTO Project ID: 2121

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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