Is the PASS the New Gold Standard for Outcome Measures?

Commentary The PROMIS (Patient-Reported Outcomes Measurement Information System) is a widely used outcome measure that is administered using computerized adaptive testing. As patient-reported outcome measures (PROMs) evolve, clinicians and investigators need to consider whether statistically significant changes in them are clinically important for patients. This paper helps to determine whether changes in the PROMIS outcomes after total ankle replacement (TAR) are clinically important by identifying the patient acceptable symptom state, or PASS. The PASS is the symptom threshold beyond which patients consider themselves well. Patient satisfaction is not achieved simply by obtaining a certain level of pain relief or functional improvement, and it can also vary depending on patient expectations as well as the diagnosis and procedure. Surgeons should therefore aim to ensure that patients have realistic expectations for TAR outcomes. This study highlights the strong association between postoperative PROMIS pain scores and the ability to achieve the PASS, showing the importance of pain reduction in patient satisfaction. Furthermore, this study identifies several preoperative variables that may affect achievement of the PASS. Patients with better preoperative physical function and mental health scores were more likely to achieve the PASS for physical function postoperatively. Patients with prior surgery, diabetes, or peripheral vascular disease were less likely to achieve the PASS for physical function. However, the PASS value can vary depending on the anchor question. There is no gold standard to capture patient satisfaction, and anchor questions with different wording might result in different thresholds. An anchor question focused on pain will not be relevant to a patient concerned about function. Thus, multiple anchors may be used to evaluate the PASS. The anchor questions used in this study specifically asked about satisfaction with the surgery and about the acceptability of current foot and ankle symptoms and function. However, the PROMs that they used were the PROMIS Physical Function (V1.2), Pain Interference (V1.1), Pain Intensity (3a, V1.0), Global Physical Health, Global Mental Health, and Depression (V1.0). None of these PROMs are foot and ankle-specific. In Figure 1, the graph shows very little change, particularly for Global Physical Health, Global Mental Health, and Depression, from before to after surgery1. So, what is the relevance of satisfaction with surgery and of foot and ankle symptoms for these outcomes? Would foot and ankle-specific PROMs result in different conclusions? The authors of this study have shown the importance of considering patient satisfaction, using PROMIS scores, and setting realistic expectations after TAR. The PASS thresholds for TAR are poorer than the population norm, so patients do not need to reach normal pain or physical function levels to have an acceptable symptom state after surgery. The overall PASS achievement rate was 84%. Thus, 1 in 6 patients did not achieve symptoms and function after TAR, similar to the rates in studies of hip and knee arthroplasty.