Within-person variability and the minimal important difference of the EQ-VAS in adults with post-COVID-19 condition: a secondary analysis of data from a single-centre randomised controlled trial.
BMJ OpenSep 25, 2026 (epub)
Julia Kopp, Tala Ballouz, Dominik Menges et al.
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In 30 seconds
This secondary analysis of a randomized controlled trial evaluated the EuroQol Visual Analogue Scale (EQ-VAS) in adults with post-COVID-19 condition (PCC). Among 153 participants, the median baseline EQ-VAS was 48.7, with a considerable day-to-day variability (median wpSD of 6.4). The study established a minimal important difference (MID) of 8 EQ-VAS points, aiding in the interpretation of health status changes in this population.
Key findings
- Median baseline EQ-VAS values were 48.7 on a 0-100 scale.
- Day-to-day variability was significant, with a median wpSD of 6.4.
- Distribution-based MID estimates ranged from 5.9 to 8.9 points.
- The anchor-based MID was determined to be 8.96 points.
Why it matters
Understanding the variability and establishing a minimal important difference for EQ-VAS in post-COVID-19 condition can enhance the assessment of patient-reported outcomes, guiding clinical decision-making and future research.