Minimal Clinically Important Differences of 3 Patient-Rated Outcomes Instruments

Abstract

Purpose Patient-rated instruments are increasingly used to measure orthopaedic outcomes. However, the clinical relevance of modest score changes on such instruments is often unclear. This study was designed to define the minimal clinically important differences (MCID) of the Disabilities of the Arm, Shoulder, and Hand (DASH), QuickDASH, and Patient Rated Wrist Evaluation (PRWE) for atraumatic conditions of the hand, wrist, and forearm. Methods One hundred two patients undergoing nonoperative treatment for isolated tendonitis, arthritis, or nerve compression syndromes from the forearm to the hand were analyzed prospectively. Patients completed the DASH, Quick DASH (subset of DASH), and PRWE at enrollment, 2 weeks (n=78 used in analysis), and 4 weeks (n=24 used in analysis) after initiating treatment by telephone. Patients reporting clinical improvement each contributed a single data point categorized as no change (n=41), minimal improvement (n=30), or marked improvement (n=31) via a validated anchor-based approach. The minimal clinically important difference was calculated as the mean change score for each outcome measure in the minimal improvement group. Results The MCID (95%CI) for the DASH was 10 (5-15). The MCID for the Quick DASH was 14 (9-20). The MCID was 14 (8-20) for the PRWE. MCID values were significantly different from changes in these outcome measures at times of either no change or marked improvement. MCID values positively correlated with baseline outcome measure scores to a greater degree than final outcome measure scores. Discussion Longitudinal changes on the DASH of 10 points, the Quick DASH of 14 points, and the PRWE of 14 points represent minimal clinically important changes. We recommend application of these MCID values for group-level analysis when conducting research and interpreting data examining groups of patients as opposed to assessing individual patients. These MCID values may provide a basis for sample size calculations for future investigation using these common patient-rated outcome measures. Level of Evidence: Diagnostic III