Getting Better or Getting Well? The Patient Acceptable Symptom State (PASS) Better Predicts Patient's Satisfaction than the Decrease of Pain, in Knee Osteoarthritis Subjects Treated with Viscosupplementation

Background. In the management of knee osteoarthritis (OA), patient-reported-outcomes (PROs) are being developed for relevant assessment of pain. The patient acceptable symptom state (PASS) is a relevant cutoff, which allows classifying patients as being in "an acceptable state" or not. Viscosupplementation is a therapeutic modality widely used in patients with knee OA that many patients are satisfied with despite meta-analyses give conflicting results. Objectives. To compare, 6 months after knee viscosupplementation, the percentage of patients who reached the PASS threshold (PASS +) with that obtained from other PROs. Methods. Data of 53 consecutive patients treated with viscosupplementation (HANOX-M-XL) and followed using a standardized procedure, were analyzed at baseline and month 6. The PROs were Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function, patient's global assessment of pain (PGAP), patient's self-assessment of satisfaction, PASS for WOMAC pain and PGAP. Results. At baseline, WOMAC pain and PGAP (range 0-10) were 4.6 (1.1) and 6.0 (1.1). At month 6, they were 1.9 (1.2) and 3.1 (5) (P < 0.0001). At 6 months, 83% of patients were "PASS + pain," 100% "PASS + function," 79% "PASS + PGAP," 79% were satisfied, and 73.6% experienced a >= 50% decrease in WOMAC pain. Among "PASS + pain" and "PASS + PGAP" subjects, 90% and 83.3% were satisfied with the treatment, respectively. Conclusion. In daily practice, clinical response to viscosupplementation slightly varies according to PROs. "PASS + PGAP" was the most related to patient satisfaction.