Background: Although minimal clinically important difference (MCID), Patient Acceptable Symptom State (PASS), and substantial clinical benefit (SCB) have been defined for hip-specific legacy patient-reported outcome measures, these metrics have not been defined for the Patient-Reported Outcomes Measurement Information System (PROMIS) instruments for patients undergoing hip arthroscopy.
Purpose: To define the MCID, PASS, and SCB thresholds for the PROMIS Physical Function (PF) computerized adaptive test (CAT) and PROMIS Pain Interference (PI) instruments in patients undergoing hip arthroscopy for femoroacetabular impingement syndrome (FAIS).
Study design: Cohort study (Diagnosis); Level of evidence, 2.
Methods: Patients undergoing primary hip arthroscopy between August 2018 and January 2019 for the treatment of FAIS were retrospectively analyzed. Patients were administered the PROMIS-PF, PROMIS-PI, Hip Outcome Score (HOS)-Activities of Daily Living, HOS-Sports Subscale, modified Harris Hip Score, and International Hip Outcome Tool-12 preoperatively and at 1 year postoperatively. MCID was calculated using the distribution method, whereas PASS and SCB were calculated using an anchor-based method. Patients achieving clinically significant outcomes (CSOs) were compared with those who did not achieve CSOs via chi-square and independent-samples t tests, and a multivariate logistic regression was conducted to determine predictors of CSO achievement.
Results: 124 patients with a mean age of 32.7 ± 12.3 years were included in the analysis. The threshold scores required to achieve MCID, PASS, and SCB, respectively, were as follows: PROMIS-PI (-3.1, 53.7, 51.9) and PROMIS-PF (3.3, 47.0, 49.9). Patients achieved any MCID, PASS, and SCB for PROMIS scores at a rate of 89.0%, 71.8%, and 62.1%, respectively, compared with 87.1%, 76.6%, and 71.8% for legacy patient-reported outcome measurements. For PROMIS-PF, higher preoperative PROMIS-PF score was a positive predictor of CSO achievement, and patients achieving SCB were significantly younger (30.3 ± 12 vs 35.6 ± 12 years; P = .017) with significantly lower body mass index (BMI) (24.7 ± 6.4 vs 27.9 ± 7; P = .009). Preoperative chronic pain and history of orthopaedic surgery were negative predictors of PROMIS-PI CSO achievement, whereas higher (worse) preoperative PROMIS-PI scores were a positive predictor.
Conclusion: Our study defined the MCID, PASS, and SCB for the PROMIS-PF CAT and PROMIS-PI CAT at 1 year postoperatively. Patients with higher preoperative PROMIS scores, younger age, and lower BMI were more likely to achieve CSO, whereas preoperative chronic pain and history of orthopaedic surgery were negative predictors of CSO achievement.
Keywords: FAI; PROMIS; femoroacetabular impingement; hip arthroscopy.