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<.001) across patient groups, differing in TNSS (F = 72.7), Physician's Global Assessment score (F = 28.6), and disease severity (F = 34.1) in the hypothesized direction. Results suggested a cut-point score of 21 or less can be used to identify patients who are experiencing rhinitis symptom control problems. The preliminary estimate of the MID was 3 points. Patients found RCAT items comprehensive, easy to understand, and relevant. Conclusion: The RCAT demonstrated adequate reliability, validity, and responsiveness and was deemed acceptable and appropriate by patients. This tool can facilitate the detection of rhinitis symptom control problems, and its brevity supports its usefulness in clinical care. (J Allergy Clin Immunol 2013;131:379-86.)