Published: August 23, 2020
Asthma is a common chronic respiratory disease affecting hundreds of millions of people worldwide of all age groups. Evaluating asthma symptoms accurately and efficiently is essential in asthma clinical research. Currently, daily symptom diaries requiring once- or twice-daily recordings are commonly used in asthma clinical trials but would be less suited to real-world use due to intensive reporting efforts.
In a recently published article in The Journal of Allergy and Clinical Immunology: In Practice, Shen and colleagues introduced a simpler method to assess asthma symptoms, called the Asthma Symptom Index (ASI) tool. The ASI is a modified version of the Asthma Symptom Utility Index (ASUI), which is a well-established, validated, and self-administered instrument for the evaluation of asthma symptoms and patients’ experience of medication side effects. The ASI is proposed as a brief patient-reported measure of asthma symptoms. The ASI excludes questions about treatment side effects and includes eight asthma symptom questions that assess frequency and severity of four core symptoms (i.e., cough, wheeze, shortness of breath, and awakening at night) over a 2-week recall period. Based on the eight questions, a symptom summary score is generated.
Shen and her colleagues conducted a study to validate the ASI tool by a post hoc analysis of data from two studies supporting the development of anti-asthma medication in patients with severe asthma. The objective was to evaluate whether the ASI is a valid asthma symptom tool that is correlated with other symptom-related measurements (e.g., daily symptom diaries, Asthma Control Questionnaire [measures adequacy of asthma control], St George's Respiratory Questionnaire [measures disease impact on quality of life]), how reliable the ASI is at detecting symptoms, how responsive it is to changes in symptoms, and the smallest difference that represents a clinically noticeable change, termed the minimal clinically important difference (MCID). Similar evaluation was also conducted for the ASUI as a confirmatory analysis, given existing evidence.
In this post hoc analysis, the ASI was reliable at detecting symptoms, and scores for the ASI had a good correlation with patient quality of life (especially in the aspect of symptom), asthma control, and daily symptom diaries. Changes in ASI and ASUI scores over time were responsive to changes detected by other symptom-related measurements. The magnitude of the MCID for the ASI was observed and defined. Taken together, the study indicates that the ASI is a valid and reliable tool which has potential value for use in real-world symptom assessment of patients with severe asthma, thereby simplifying the monitoring of patients in a real-world setting.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.