Early-stage vs established knee osteoarthritis: A comparative observational study on prevalence and changes in pain, function and quality of life after supervised exercise and education among 10,365 patients

Objective: 

Compare prevalence and changes in outcomes among established and early-stage knee osteoarthritis (KOA) patients undertaking supervised exercise and education. 

Methods: 

Patients from Good Life with osteoArthritis in Denmark (GLA:D®) were stratified into three groups: established KOA (ACR/EULAR criteria), early-stage KOA (diagnostic-model-outcome ≥70%, Criteria for the Early Diagnosis of knee Osteoarthritis) or potential early-stage KOA (diagnostic-model-outcome 30–69%). Mixed-effects models and the proportion of patients by group achieving minimal clinically important improvements (MCIIs) were used to investigate changes in VAS pain intensity (0–100mm), Knee injury and Osteoarthritis Outcome Score (KOOS) Quality of Life (QoL; 0–100), 40 m Walk test and 30 s chair-stand test at 3 and 12 months. 

Results: 

Compared to established KOA (61% of 10,365 patients), early-stage KOA (27%) had similar knee pain at baseline (mean (standard deviation); 51 (22) vs 45 (22)), and improvement in pain (mean (95% confidence interval) −15 (−15 to −14) vs −14 (−15 to −13), ≥MCII: 55% vs 54%) and KOOS QoL (≥MCII: 50% vs 50%) at 12 months, and in walking speed (≥MCII: 56% vs 52%) and chair-stands (≥MCII: 55% vs 52%) at 3 months. Compared to either group, potential early-stage KOA (10%) had lower baseline pain (34 (32.7)) and less improvement in pain (−9.8 (−11.3 to −8.2; ≥MCII: 47%)), but comparable improvements in KOOS QoL (≥MCII: 50%), walking speed (≥MCII: 51%) and chair-stands (≥MCII: 51%).

Conclusion: 

Patients with early-stage KOA achieved comparable improvements at 3 and 12 months to those with established KOA, supporting supervised exercise and education as a viable management strategy for early-stage KOA.