Non-inferiority of short-term urethral catheterization following fistula repair surgery: study protocol for a randomized controlled trial

Abstract

Background: A vaginal fistula is a devastating condition, affecting an estimated 2 million girls and women across Africa and Asia. There are numerous challenges associated with providing fistula repair services in developing countries, including limited availability of operating rooms, equipment, surgeons with specialized skills, and funding from local or international donors to support surgeries and subsequent post-operative care. Finding ways of providing services in a more efficient and cost-effective manner, without compromising surgical outcomes and the overall health of the patient, is paramount. Shortening the duration of urethral catheterization following fistula repair surgery would increase treatment capacity, lower costs of services, and potentially lower risk of healthcare-associated infections among fistula patients. There is a lack of empirical evidence supporting any particular length of time for urethral catheterization following fistula repair surgery. This study will examine whether short-term (7 day) urethral catheterization is not worse by more than a minimal relevant difference to longer-term (14 day) urethral catheterization in terms of incidence of fistula repair breakdown among women with simple fistula presenting at study sites for fistula repair service.

Methods/design: This study is a facility-based, multicenter, non-inferiority randomized controlled trial (RCT) comparing the new proposed short-term (7 day) urethral catheterization to longer-term (14 day) urethral catheterization in terms of predicting fistula repair breakdown. The primary outcome is fistula repair breakdown up to three months following fistula repair surgery as assessed by a urinary dye test. Secondary outcomes will include repair breakdown one week following catheter removal, intermittent catheterization due to urinary retention and the occurrence of septic or febrile episodes, prolonged hospitalization for medical reasons, catheter blockage, and self-reported residual incontinence. This trial will be conducted among 512 women with simple fistula presenting at 8 study sites for fistula repair surgery over the course of 24 months at each site.

Discussion: If no major safety issues are identified, the data from this trial may facilitate adoption of short-term urethral catheterization following repair of simple fistula in sub-Saharan Africa and Asia.

Trial registration: ClinicalTrials.gov Identifier NCT01428830.

Figures

Figure 1

Trial profile. Women who consent to participate in the study may be determined ineligible prior to randomization: (1) at the time of surgery if the surgeon determines that the fistula is 'not simple': (2) at the end of surgery if the fistula is not closed based on dye test results; and (3) 7 days after surgery if the fistula is not closed based on dye test results. Seven days after surgery, women with a closed fistula will be randomized to catheter removal on that day (i.e. the 7-day removal group) or to have the catheter kept in place for an additional 7 days (i.e. the 14-day removal group). Women will remain at the study site for an additional 7 days after catheter removal. On days 1, 3 and 7 after catheter removal, urine retention will be assessed and intermittent catheterization employed as needed. Women with a positive urinary dye test at 7 days following catheter removal will be classified as having experienced a repair breakdown and their participation in the study will be completed. Remaining women will be asked to return for a follow-up visit 3 months after the date of surgery.

Figure 2

Interpreting results of non-inferiority trials [11]. Footnotes for Figure 2. *This CI indicates noninferiority in the sense that it does not include Δ, but the new treatment is significantly worse than the standard. Such a result is unlikely because it would require a very large sample size. †This CI is inconclusive in that it is still plausible that the true treatment difference is less than Δ, but the new treatment is significantly worse than the standard.