Baseline knee osteoarthritis radiographic severity as a predictor of symptom response to diet and exercise program: A secondary analysis

To investigate whether baseline joint space narrowing (JSN) predicted disease remission, knee pain, and physical function changes in persons with knee osteoarthritis (OA).This study is a secondary analysis of a two-armed randomized controlled trial. Participants were aged ≥50 years (n = 171) with a body mass index ≥28 kg/m2 and radiographic medial tibiofemoral OA. Participants in the intervention group received diet and exercise programs and special treatment (cognitive behavioral therapy, knee brace, and muscle strengthening exercises) according to the disease remission. Remission of pain and remission of patient global assessment of disease activity and/or functional impairment were used to define the disease remission. The control group were provided with an education pamphlet. The primary outcome was disease remission at 32 weeks, and the secondary outcomes were the changes in knee pain and physical function at 20 and 32 weeks. Baseline JSN was scored from 0 to 3, and the association between baseline JSN and outcomes was assessed using multiple regression.There was no association of baseline JSN with disease remission at 32 weeks when the disease remission has been achieved. The baseline JSN grade 3 was associated with changes in knee pain at 20 weeks (p < .05). There was no association between baseline JSN and physical function.Baseline JSN severity predicted changes in knee pain but not the disease remission or changes in physical functions. Identification of baseline radiographic severity may be helpful in identifying differences in response to diet and exercise programs in knee OA.