Identifying factors associated with clinical success in patients treated with NASHA ® /Dx injection for fecal incontinence

Injection with the bulking agent consisting of non-animal stabilized hyaluronic acid/dextranomer (NASHA(®)/Dx) is well tolerated and efficacious for the treatment of fecal incontinence (FI); however, the patient population that may derive maximum benefit has not been established. This post hoc responder analysis assessed demographic and baseline characteristics predictive of responsiveness to NASHA/Dx treatment.Adults with a Cleveland Clinic Florida fecal incontinence score (CCFIS) ≥10 were randomized to receive NASHA/Dx or sham treatment. The primary end point was response to treatment (ie, decrease from baseline of ≥50% in number of FI episodes) at 6 months; a prespecified secondary end point was change in fecal incontinence quality of life (FIQL) score at 6 months. Post hoc subgroup analyses were performed for baseline and demographic characteristics and prior FI treatments.Overall, response to treatment was significantly greater with NASHA/Dx versus sham injection (52.7% vs 32.1%; P=0.0089). All subgroups analyzed demonstrated evidence of improvement, favoring NASHA/Dx versus sham treatment for both response to treatment and change in the FIQL coping/behavior subscale score. For the primary end point, a significantly greater percentage of patients with CCFIS ≤15, FI symptoms ≤5 years' duration, or obstetric causes of FI responded to NASHA/Dx treatment versus patients receiving sham treatment (51.1% vs 28.3%, P=0.0169; 55.4% vs 25.7%, P=0.0026; and 53.6% vs 23.1%, P=0.0191, respectively). The mean change in the FIQL coping/behavior score significantly favored NASHA/Dx versus sham treatment for patients with CCFIS ≤15 (P=0.0371), FI symptoms ≤5 years' duration (P=0.0289), or obstetric causes of FI (P=0.0384). Patients without a history of specific FI treatments (eg, antidiarrheal medications, biofeedback, surgery) were more likely to respond to NASHA/Dx versus sham treatment for both end points.Although all subgroups analyzed showed evidence of quantitative and qualitative benefit from NASHA/Dx therapy, patients with characteristics indicative of mild-to-moderate FI may exhibit the greatest benefit.