Criterion validation of the rate of recovery, a single alphanumeric measure, in patients with shoulder pain

Background and purpose: The aim of this study was to identify the minimal clinically important threshold score for rate of recovery (RoR) using the Patient Acceptable Symptom State (PASS) as an anchor measure, and to measure the association of the RoR with the raw and percentage change scores of the QuickDASH and the Numeric Pain Rating Scale (NPRS).

Methods: Threshold measures for RoR and the PASS were examined using a Receiver Operating Characteristic (ROC) Curve. Participants were dichotomized to those who stated "yes" and those who stated "no" on the PASS. Pearson correlation coefficients were performed to determine the relationship between the NPRS and QuickDASH raw and percentage change scores and the RoR at discharge.

Results: ROC curve statistics suggest that a cut-point of greater than 87% on the self-report RoR (SN=0.62, SP=0.73; +LR=2.26: -LR=0.56) corresponded to the patient considering their state acceptable. No significant associations existed between either the raw NPRS or the raw QuickDASH, and the RoR scores although percentage change scores were associated with the RoR (QuickDASH r=0.29; p=0.02; NPRS = r=0.30; p=0.02).

Discussion: Patients reporting greater than or equal to 87% on RoR are likely to have met the Patient Acceptable Symptom State. Although statistically significant, the lack of strong association between RoR and change scores for the NPRS and QuickDASH suggests that the measures capture different constructs.

Level of evidence: Level 2C.