Identification of phenotypes with different clinical outcomes in knee osteoarthritis: Data from the osteoarthritis initiative

The aim of this research was to identify subgroups or phenotypes of knee osteoarthritis (OA) patients based on similarities of clinically relevant patient characteristics, and to compare clinical outcomes of these phenotypes. Data from 842 knee OA patients of the Osteoarthritis Initiative were used. A cluster analysis method was performed, in which clusters were formed based on similarities in 4 clinically relevant, easily available variables: severity of radiographic OA, lower extremity muscle strength, body mass index, and depression. Univariable and multivariable regression analyses were used to compare phenotypes on clinical outcomes (pain and activity limitations), taking into account possible confounders.