Validating endpoints for therapeutic trials in fecal incontinence

Area of Science:

• Gastroenterology
• Clinical Trials
• Patient-Reported Outcomes

Background:

• The primary endpoint for fecal incontinence (FI) clinical trials is a 50% or greater reduction in FI frequency, but its clinical importance is not well-established.
• The correlation between daily and weekly FI symptom assessments and the impact of psychological factors on quality of life (QOL) in FI patients require further clarification.

Purpose of the Study:

• To determine if a 50% or greater reduction in FI frequency represents a clinically important improvement.
• To investigate the relationship between daily and weekly FI symptom measurements.
• To explore the contribution of psychological factors to QOL in women with FI.

Main Methods:

• 44 women with FI completed daily bowel diaries and weekly questionnaires assessing FI severity (FISS, FIQOL, SF-36, HADS) for 4 weeks.
• FI frequency reduction was compared to the minimal clinically important difference (MCID) derived from the FISS.
• Daily and weekly FI assessment parameters were compared.

Main Results:

• The Fecal Incontinence Severity Score (FISS) exceeded the MCID in 75% and 83% of patients with 50-74% and ≥75% FI frequency reduction, respectively.
• Daily and weekly FI measurements showed significant correlations, with daily parameters explaining 71% of FISS variation.
• 36-Item Short Form Health Survey (SF-36) scores, not FISS, primarily explained variance in FIQOL.

Conclusions:

• A ≥50% reduction in FI frequency generally indicates a clinically meaningful improvement for patients.
• Weekly questionnaires are effective tools for assessing FI severity.
• Self-reported physical and mental health status are stronger predictors of FIQOL than FI symptom severity itself.