The aims of this study are (1) to establish the Patient Acceptable Symptom State (PASS) cutoff values of different patient-reported outcome measures (PROM) assessing physical function in patients with knee osteoarthritis (OA), and (2) to assess the influence of sex, age, duration of symptoms, and presence of depressive feelings on being in PASS.
Patients fulfilling the clinical American College of Rheumatology knee OA criteria received standardized nonsurgical treatment and completed different questionnaires at baseline and 3 months assessing physical function: Knee Injury and Osteoarthritis Outcome Score, Lequesne Algofunctional Index, Lower Extremity Functional Scale, numerical rating scale, and the physical function subscale of the Western Ontario and McMaster Universities Osteoarthritis Index. PASS values were defined as the 75th percentile of the score of questionnaires for those patients who consider their state acceptable.
Of the 161 included patients, 62% were women with a mean age of 59 years (SD 9) and body mass index of 30 kg/m
PASS cutoff values for physical function are robust across different PROM in patients with knee OA. Our results indicate that PASS values are not consistent across dimensions and rheumatic diseases, and that the use of a generic PASS value for patients with OA or even patients with other rheumatic diseases might not be justifiable.