Utility of the Patient Acceptable Symptom State (PASS) and Single Simple Question (SSQ) in a Malaysian myasthenia gravis cohort

Abstract

Background & Objective: Assessing myasthenia gravis (MG) can be challenging and multiple outcome measures have been developed to evaluate disease severity. Both the Patient Acceptable Symptom State (PASS) and the Single Simple Question (SSQ) are validated patient-reported outcome measures, but they assess different dimensions of MG. In this study, we aimed to assess the utility of PASS and SSQ in a Malaysian cohort of patients with MG.

Methods: In this cross-sectional study, patients with MG followed-up at the neurology clinic of University Malaya Medical Centre from July 2023 to October 2023 were invited to participate. Data on demographic and clinical characteristics were collected. Patients were required to complete the PASS, SSQ, Myasthenia Gravis Activities of Daily Living (MG-ADL) and Myasthenia Gravis 15-item Quality of Life Revised (MG-QOL15R) questionnaires. Additionally, the Myasthenia Gravis Composite Scale (MGCS) was scored by the physicians during their review.

Results: A total of 71 patients were included. One-third (32.4%) of patients were dissatisfied (PASS-negative) with their current MG symptom state. Of note, significantly more Indians (26.1%) responded ‘No’ to PASS, while more Chinese (81.3%) responded ‘Yes’. Patients with a PASS-negative response had lower SSQ scores (59.1±22.4% vs 80.4±19.0%, p<0.001) and higher MG-ADL (3.9±3.4 vs 1.8±2.0, p=0.011) and MG-QOL15R (11.2±7.3 vs 4.3±4.8, p<0.001). SSQ also showed significant correlations with MG-ADL (r=–0.53, p<0.001), MG-QOL15R (r=–0.40, p=0.001) and MGCS (r=–0.39, p=0.001). An SSQ score of ≥62.5% had 89.6% sensitivity in classifying patients as PASS-positive. PASS thresholds for MG-ADL, MG-QOL15R and MGCS were ≤3.5, ≤6.5 and ≤2.0 points, respectively.

Conclusion: PASS and SSQ are closely associated, and an SSQ threshold of ≥62.5% predicts an acceptable MG state. Both PASS and SSQ are feasible, valid measures and may be easily incorporated into routine MG clinical assessment.