Clinical relevance of health-related quality of life outcomes with darifenacin

Abstract

Objective: To determine the clinical relevance of changes in health-related quality of life (HRQoL) in patients with overactive bladder (OAB) treated with darifenacin.

Patients and methods: Data were pooled from three randomized, placebo-controlled, parallel-group, fixed-dose, 12-week studies. After 2-week washout, treatment-free or placebo run-in periods, patients with OAB (n = 1059; 85% women; age 19-88 years) were randomized to 12 weeks' treatment with darifenacin controlled-release 7.5 mg (n = 337) or 15 mg once daily (n = 334) or placebo (n = 388). The King's Health Questionnaire (KHQ) was used to assess HRQoL at baseline and Week 12. The clinical significance of changes in KHQ domain scores was assessed using the concept of minimum important difference (MID), using two different methods.

Results: Darifenacin treatment was associated with significantly greater improvements than placebo in six primary KHQ domain scores known to be of importance to patients with OAB. In addition, a significantly greater proportion of darifenacin-treated patients met or exceeded reference MID vs placebo in these domains (Incontinence Impact, Severity Measures, Role Limitations, Social Limitations, Emotions and Physical Limitations; P = 0.01). In darifenacin-treated patients, there were significant correlations between the reductions in incontinence episodes per week and improvements in KHQ scores (P < 0.001). The strongest correlations were in the Incontinence Impact, Social Limitations, Role Limitations, Severity Measures and Emotions domains.

Conclusions: Darifenacin treatment was associated with significant, clinically relevant improvements in HRQoL in patients with OAB, shown using the concept of MID to interpret change in KHQ scores.