What is considered to be a clinically important change for the DASH/QuickDASH?

The minimum clinically important difference (MCID) is considered the smallest change or difference in an outcome measure that is perceived to be important (Wells 2001). There are different methods (Wells 2001) and viewpoints (patient, clinicians) that may be used to determine the MCID. We have found considerable variability due to the effect of the method used, of the time window, and of whether the change was important or not (with DASH MCID values ranging from 3.9 to 15). These are important differences, and this variability is likely is present in many other tools as well but never tested. Our work has shown us that there is reason to be skeptical about hard and fast claims of a single MCID value. However, when we worked through all the findings, we decided that a change in DASH score exceeding 15 points is the most accurate change score for discriminating between improved and unimproved patients (Beaton 2001a; 2001b). This and other indicators place the MCID at, or below, our current understanding of the minimal detectable change at the 95% confidence level (MDC₉₅). The MDC can be computed at varying confidence levels. It is the minimum change score that must be observed before a clinician can be confident that a change in patient status has occurred rather than measurement error (Beaton 2000c). An individual-level change below the MDC is difficult to interpret because it could just be the day-to-day variability in the score rather than an important change. Since some MCID work is placing the MCID at approximately the same value as the MDC₉₅, it is reasonable to consider the MDC₉₅ as an interim proxy for the MCID. MDC₉₅ was calculated for the DASH across six different study populations and ranged from 8 to 17 DASH points (with a mean of 13).

For the QuickDASH, we have approached the clinically important change question in the same manner. To date, only one study has looked at the MCID of the QuickDASH and reported that a change exceeding 8 points is the most accurate change score for discriminating between improved and stable patients (Mintken 2009). Since this study is placing the MCID at a value lower than the MDC₉₅, it is reasonable to consider the MDC₉₅ as an interim proxy for the MCID. MDC₉₅ was calculated for the QuickDASH across three different study populations and ranged from 16 to 20 QuickDASH points (with a mean of 18).