Linking diabetes to worsening knee osteoarthritis symptoms and disability: evidence from the osteoarthritis initiative

Objective To examine the impact of baseline diabetes mellitus (DM) on longitudinal knee symptoms and disability in participants with knee osteoarthritis (OA). Methods This was a secondary analysis using publicly available data from a longitudinal study design (Osteoarthritis Initiative). Data from 4,796 participants (45–79 years of age) were obtained, and only participants with grade ≥2 in either knee, using the Kellgren and Lawrence grading at baseline, were included in the current analysis. Based on self-reported DM, the participants were categorized into two groups: knee OA and DM or knee OA only. Symptoms and disability were measured using the Western Ontario and McMaster Universities Arthritis Index (WOMAC) scale and pain severity across 7- and 30-days at seven visits from baseline to 96 months of follow up. Results A total of 2,486 participants were included and categorized into knee OA and DM ( n = 221) and knee OA only ( n = 2,265). The longitudinal analyses results ( n = 2,483) showed that participants with knee OA and DM had significantly increased knee symptoms over time using the WOMAC total score [beta ( B ) = 3.20, p = 0.004], WOMAC pain subscale ( B = 0.71, p = 0.003), WOMAC stiffness subscale ( B = 0.22, p = 0.036), and WOMAC disability subscale ( B = 2.26, p = 0.005) compared with participants with knee OA only. Knee OA and DM was not associated with increased knee pain severity over a 7-day period ( B = 0.28, p = 0.10) and over a 30-day period ( B = 0.20, p = 0.23) when compared to knee OA only. Conclusion This longitudinal cohort study provides evidence supporting the association between baseline DM and increased knee symptoms and disability among individuals with knee OA.