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Completed

NCT Number: NCT04549311

Perianal Abscess Recurrence and Fistula Formation: Antibiotics Following Incision and Drainage Trial

Most perianal abscesses (PA) result from an infection originating in anal crypts that extend into anal glands in the intersphincteric plane. Patients commonly present to the ER and usually require surgical intervention, which poses a burden on the healthcare system. If left undrained, a PA can expand into the adjacent tissues as well as progress to systemic infection. One of the major complications of PA are perianal fistulae; the creation of a tract between the anal canal and the perianal skin that is lined with granulation tissue or skin cells. Up to 1/3 of patients with a PA will develop a fistula; which occurs if a PA drains spontaneously through the perianal skin, and the infection becomes chronic. If this happens, surgical intervention is needed and abscesses may reoccur. Post incision and drainage (I&D) antibiotics in PA have been used to address complications but their use is still controversial and there are no specific recommendations on their use to prevent the formations of fistulae.

Recent findings from a systematic review (6 studies, N=817 patients) published in 2019 demonstrated that antibiotic use following I&D of PA was associated with a 36% lower odds of fistula formation, though the quality of the evidence was low.

As there are no established prophylactic treatments for fistulae, and because they are difficult to treat, further study of this simple intervention seems warranted. In this trial, adults with a PA requiring I&D will be randomly assigned to receive standard of care with antibiotics or standard of care without antibiotics after I&D. 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 are incidence of fistula formation (defined as drainage of the perianal region at or after 2 months), need for re-intervention (i.e., any intervention on the perianal region), quality of life, healthcare utilization, healing time and mortality.

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Key information

Conditions

Perianal Abscess Perianal Fistula

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

North York General Hospital, North York, Ontario, Canada

Loading trial locations.

About this study

The development of perianal abscesses is relatively common with an estimated incidence in the UK of 40 per 100,000 habitants (Canadian incidence unknown). It is uncertain if there is any benefit to using prophylactic antibiotics after incision and drainage of a perianal abscess in order to reduce the formation of fistulae, the need for re-intervention, health system costs, and healing time. Further research from high-quality RCTs is needed to establish a benefit, if any, for this practice.

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

  • To assess our ability to accrue patients using the IMPACTS Program design platform at multiple institutions, over the course of one year.
  • To assess our ability to adaptively randomize patients and deliver the randomized assignment using the IMPACTS Program design platform, over the course of one year.
  • To assess our ability to collect complete data directly from participants (patients and clinicians) on: re-intervention, fistula formation, quality of life, and healing time over the course of one year.
  • To examine our ability to carry out data linkages using the IMPACTS Program design platform over the course of one year.
  • To estimate the incidence of fistula formation to inform the sample size calculation for the definitive trial.

Study design: This is a multicentre, pragmatic, open label, three-arm parallel-group Vanguard feasibility randomized controlled trial. Adult patients with perianal abscesses requiring incision and drainage will be randomized to receive standard of care with antibiotics or standard of care without antibiotics after incision and drainage. 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).

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patients aged ≥18 years
  • Perianal abscess requiring incision and drainage

Exclusion criteria

  • Allergies or contraindications to amoxicillin + clavulanic acid, penicillin, ciprofloxacin, or metronidazole
  • Definite need to be on antibiotics at the treating clinicians' discretion
  • Immunosuppression such as: human immunodeficiency virus (HIV), chronic steroids treatment, current chemotherapy
  • Abscess associated with Inflammatory Bowel Disease (IBD)
  • Supralevator perianal abscess
  • Recurrent perianal abscesses within 5 years
  • Known rectal cancer diagnosis within 5 years
  • History of pelvic radiotherapy within 5 years

Treatment and study plan

Antibiotic 1 arm (amoxicillin + clavulanic acid)

Drug

Prescription of antibiotics (amoxicillin + clavulanic acid) after incision and drainage of perianal abscess.

Antibiotic 2 arm (ciprofloxacin + metronidazole)

Drug

Prescription of antibiotics (ciprofloxacin + metronidazole) after incision and drainage of perianal abscess.

Primary outcomes

  1. Total number of participants accrued across all sites, per month

    Time frame: 1 year

    Feasible if 3 or more patients accrued per month between all sites

  2. Proportion of participants who received the allocated intervention, across all sites

    Time frame: 1 year

    Feasible if >90% of patients receive correct intervention

  3. Proportion of complete data collection for patient-reported outcome surveys, across all sites

    Time frame: 1 year

    Feasible if >80% of data is collected

  4. Proportion of successful data linkage of patient-reported outcome data with Institute of Clinical Evaluative Sciences dataset(s)

    Time frame: 1 year

    Feasible if linkage is possible in >90% of patients

  5. Estimation of fistula formation in three groups

    Time frame: 1 year

    Rate of fistula formation in the three groups

Sponsors and collaborators

Lead sponsor

Sunnybrook Health Sciences Centre

Other

Registry information

Official study title

Perianal Abscess Recurrence and Fistula Formation: Antibiotics Following Incision and Drainage Trial - (PARFAIT) A Vanguard Randomized Controlled Trial

Acronym: PARFAIT

Important dates

Study start
2021
Primary completion
2023
Study completion
2023
First posted
Sep 16, 2020
Registry last updated
Jan 12, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

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This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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