The minimal clinically important difference of patient-reported outcome measures in adults with asthma: a systematic...

Patient-reported outcome measures (PROMs) are widely used to assess symptom control and quality of life in adult asthma clinical trials, but interpreting score changes requires knowledge of the minimal clinically important difference (MCID). This review aimed to identify asthma-specific PROMs with established MCID values, summarize estimation methods, and evaluate the credibility of anchor-based MCID estimates.

Following PRISMA guidelines, PubMed, Embase, and Web of Science were searched in March 2025 for original studies reporting MCID values for asthma-specific PROMs in adults. Non-English language publications were excluded. Study characteristics, estimation methods, and credibility (assessed using a nine-item instrument) were narratively summarized.

19 studies were included, covering 15 validated asthma-specific PROMs and 21 MCID estimates. Most estimates were derived from populations with persistent asthma, with four focus on severe asthma and four on asthma with comorbid allergic rhinitis. The majority of interventions involved guideline-based usual care. Anchor-based methods, including mean change analysis, were predominantly used to derive MCID values, with some studies supplementing these with distribution-based methods such as one standard error of measurement. Only 15% of MCID estimates were rated as high credibility, while 75% were rated as low. Key methodological limitations included unclear anchor thresholds and a lack of anchor-PROM correlation reporting.

MCID values are vital for interpreting PROM changes in asthma research but show considerable methodological variability. Standardization and transparency in MCID estimation are needed to enhance their validity and clinical utility.

CRD42023431560, June 12, 2023.