Reliability, validity, and responsiveness of the Rhinitis Control Assessment Test in patients with rhinitis

Background The Rhinitis Control Assessment Test (RCAT) is a brief, patient-completed tool to evaluate rhinitis symptom control. Objective We sought to test the reliability, validity, and responsiveness of RCAT and to estimate a cut-point score and minimal important difference (MID). Methods A total of 402 patients 12 years of age and older with allergic or nonallergic rhinitis were enrolled in a noninterventional study. Patients completed the RCAT (6 items; score range, 6-30) and had Total Nasal Symptom Scores (TNSSs) measured at baseline and 2 weeks later. Physicians completed a global assessment of rhinitis symptom control (Physician's Global Assessment) and disease severity. Internal consistency, test-retest reliability, convergent validity, known-groups validity, and responsiveness were evaluated. The MID was determined by using distribution- and anchor-based methods. Content validity of the RCAT was assessed in individual interviews with a separate group of 58 adult patients. Results Internal consistency and test-retest reliability of RCAT scores were 0.77 and 0.78, respectively. Convergent validity correlation between RCAT and TNSS scores was 0.57, and that between RCAT and Physician's Global Assessment scores was 0.34. Mean RCAT scores differed significantly ( P