Associations Among Knee Osteoarthritis Severity, Body Mass Index, and Physical Functions in Saudi Arabian Adults: A Multi-Center Cross-Sectional Study

Background The purpose of this study was to investigate the associations among knee osteoarthritis severity, body mass index, and physical functions in Saudi Arabian adults. Methodology In this multi-center, cross-sectional study, we performed a secondary data analysis that included 189 adults aged 55 years or above with doctor-diagnosed knee osteoarthritis enrolled in five hospitals in Riyadh, Saudi Arabia, between March 2016 and March 2017. According to knee osteoarthritis severity, all of the individuals were divided into the following three groups: mild (n = 36), moderate (n = 75), and severe (n = 78). A high body mass index was defined as a body mass index score of >25 kg/m2. Physical function was evaluated using the 36-item physical functioning subscale. Results Severe knee osteoarthritis had a significantly 6.47-fold (95% confidence interval (CI) = 2.95-14.22, p < 0.0001) higher risk of physical function than those with mild knee osteoarthritis after adjusting for age, sex, educational status, occupational status, affected knee with osteoarthritis, knee pain, and body mass index. However, moderate knee osteoarthritis had a 1.22-fold higher risk of physical function, but the association was not statistically significant (95% CI = 0.60-2.49, p = 0.578). Conclusions Severe but not moderate knee osteoarthritis was more likely to have the worst physical function than mild knee osteoarthritis among adults with a high body mass index in Saudi Arabia.