RESUMEN
BACKGROUND: Allergic rhinitis and asthma are common and closely related diseases. Recently, a Portuguese questionnaire has been developed 'The Control of Allergic Rhinitis and Asthma Test' (CARATkids) that measures disease control of both diseases in children. This study aims to validate the CARATkids in Dutch children and for the first time in adolescents and, in addition, to calculate the minimal clinically important difference (MCID). METHODS: A prospective observational study was conducted in an outpatient clinic. After translation of the CARATkids from Portuguese to Dutch, patients (6-18 years) with asthma or asthma and allergic rhinitis completed the CARATkids, Asthma Control Test, and visual analog scale questionnaire three times. Baseline characteristics, mean scores, internal consistency, test-retest reliability, cross-sectional and longitudinal validity, discriminative properties, responsiveness, and MCID of the CARATkids were assessed. RESULTS: A total of 111 patients were included. In total, 86% and 79%, respectively, completed the questionnaires at the second and third visits. All children had asthma, and 85% had concomitant allergic rhinitis. The internal consistency was good with all expected a priori correlations met. CARATkids scores were higher in patients with uncontrolled asthma and patients with moderate-severe rhinitis compared to better controlled subjects. Patients with a variable asthma control had significantly higher scores during periods of uncontrolled asthma. Also the Guyatt's responsiveness index was good. The MCID was 2.8. CONCLUSIONS: The CARATkids questionnaire is a reliable and valid tool to assess allergic rhinitis and asthma control among Dutch children. The tool can be used in adolescents.