Establishing the Patient-Acceptable Symptom State for the Numeric Rating Scale-Pain Score in a Postoperative Non-Shoulder Hand and Upper-Extremity Population.

PURPOSE

The patient-acceptable symptom state (PASS) is a threshold score on a patient-reported outcome measurement beyond which patients consider themselves "well." Our purpose was to establish the PASS for the numeric rating scale (NRS) for pain in a 1-year postoperative hand surgery population.

METHODS

This retrospective study included adult patients undergoing non-shoulder upper-extremity surgery at a single, tertiary medical center identified over a 9-month period. At 1 year after surgery, NRS pain and responses to a pain-specific anchor question were collected. Patients were dichotomized based on achieving "PASS(+)" or failing to achieve "PASS(-)" an acceptable symptom state based upon their response to a pain-specific anchor question. Threshold values of a PASS(+) state were calculated for the NRS pain score using the following three methods: (1) mean score of PASS(+) patients, (2) Tubach method (75th percentile threshold for PASS(+) patients), and (3) the Youden index (receiver operating curve analysis to maximize sensitivity and specificity).

RESULTS

Of 233 included patients, mean age was 54 years (±17), and 58% (n = 136) were women. Mean NRS pain scores differed between PASS(+) and PASS(-) patients (0.7 ± 1.2 vs 3.8 ± 2.7, respectively). PASS(-) patients were more likely to be non-White and have a diagnosed psychiatric comorbidity. Patient-acceptable symptom state estimates ranged from 0.73 to 2.1 for NRS pain, depending on the calculation method (0.73 for the mean score method, 1.0 for the Tubach method, and 2.1 for the Youden index). The area under the curve for the Youden index method was 0.86 consistent with excellent discrimination.

CONCLUSIONS

We propose the value of 2.1 to represent the PASS threshold for the NRS pain score in this population.

CLINICAL RELEVANCE

This PASS value should be used when interpreting NRS pain score outcomes at a population level. This threshold is expected to yield excellent discrimination for patient satisfaction when applied to a postoperative hand surgery population.