Asthma Daytime Symptom Diary (ADSD) and Asthma Nighttime Symptom Diary (ANSD): Measurement Properties of Novel Patient-Reported Symptom Measures

Abstract

Background: The Asthma Daytime Symptom Diary (ADSD) and the Asthma Nighttime Symptom Diary (ANSD) were developed to meet the need for standardized patient-reported measures of asthma symptoms to assess treatment trial outcomes in adults and adolescents.

Objective: To determine scoring and evaluate the measurement properties of the ADSD/ANSD.

Methods: Adolescents (12-17 years) and adults (18+ years) with asthma completed draft 8-item electronic versions of the ADSD/ANSD for 10 days alongside the Adult Asthma Symptom Daily Scales (AASDS) and a Patient Global Impression of Severity (PGIS). Using classical and modern psychometric methods, initial analyses evaluated the performance of ADSD/ANSD items to inform scoring. Subsequent analyses evaluated the reliability and validity of ADSD/ANSD scores.

Results: A demographically and clinically diverse sample (n = 130 adolescents; n = 89 adults) was recruited. Item performance was generally strong. However, items assessing chest pressure and mucus/phlegm demonstrated redundancy and poorer performance and were removed. Principal-components analysis, confirmatory factor analysis, and item response theory supported combining items to form 6-item total ADSD/ANSD scores. Internal consistency (α = 0.94-0.95) and test-retest reliability (intraclass correlation coefficient = 0.86-0.95) were strong. Strong correlations (r = 0.72-0.80) were observed between ADSD scores and AASDS items assessing asthma symptom frequency, bother, and impact on activities. Significant differences (P < .001) in mean ADSD/ANSD scores were observed between groups categorized by asthma severity (PGIS), asthma control, inhaler use, nebulizer use, activity limitations, and nighttime awakenings.

Conclusions: The ADSD/ANSD items and scores demonstrated strong reliability and validity. Implementation of the measures in interventional studies will enable the evaluation of responsiveness and meaningful within-patient change.

Keywords: Asthma; Clinical outcome assessment; Patient-reported outcome measure; Reliability; Validity.