St. George's Respiratory Questionnaire: MCID

The SGRQ is a disease-specific measure of health status for use in COPD. A number of methods have been used for estimating its minimum clinically important difference (MCID). These include both expert and patient preference-based estimates. Anchor-based methods have also been used. The calculated MCID from those studies was consistently around 4 units, regardless of assessment method. By contrast, the MCID calculated using distribution-based methods varied across studies and permitted no consistent estimate. All measurements of clinical significance contain sample and measurement error. They also require value judgements, if not about the calculation of the MCID itself then about the anchors used to estimate…