The following is a summary of the “Harmonising knee pain patient-reported outcomes: a systematic literature review and meta-analysis of Patient Acceptable Symptom State (PASS) and individual participant data (IPD),” published in the January 2023 issue of Osteoarthritis and Cartilage by Georgopoulos, et al.

Using the Patient Acceptable Symptom State scores (PASS) as a criterion, we investigated the harmonization of patient-reported outcome measures (PROMs) in patients with knee pain related to osteoarthritis or knee injuries. Individual participant data (IPD) analysis of score distributions from concurrently completed PROM pairs was conducted, and a systematic literature review (SLR) was conducted on PASS scores. The KOOS and WOMAC pain questionnaires and other numerical rating scales, visual analog scales, and other pain assessment tools were all standardized to a 0 to 100 (worst) range. relationships with PASS were investigated using meta-regression. 

Intra-individual comparisons of PROM scores were made using IPD from the WebEx, KICK, MenTOR, and NEKO trials, and the results were compared using Bland Altman plots.

SLR found 18 studies that mentioned PASS in relation to persons with knee discomfort. The average PASS across all participants was 27 (95% CI, 21-35; n=6,339). Each standardized PROM had a similar PASS, statistically speaking. However, baseline pain was lower in those with a lower PASS (β=0.49, P=0.01), and the length of time, until treatment was started, was greater in those with a lower PASS (Q = 6.35, P = 0.04).

The PASS score was lowest for ligament rupture (12; 95% CI; 11-13), and it was similar for knee osteoarthritis (31); 95% CI; 26-36) and meniscal tear (27; 95% CI; 20-35). While the mean scores across all standardized PROMs for IPD were similar, there was significant variation between PROMs for individual patients (LoA between −7 to −38 and +25 to 52).

The PASS criteria from several standardized PROMs for group data are very comparable. Patient and therapy factors may impact PASS thresholds more than differences between PROMs. However, scores on the various PROMs vary from person to person, which may reflect the fact that people’s perceptions of pain are distinct.

Source: sciencedirect.com/science/article/pii/S1063458422008299