Association between symptomatic knee osteoarthritis and health-related quality of life in individuals with type 2 diabetes: A cross-sectional study

Objective: Knee osteoarthritis (OA) and type 2 diabetes (T2D) commonly coexist, but their combined impact on health-related quality of life (HRQoL) remains understudied. We assessed the association between symptomatic knee OA and HRQoL in individuals with T2D and explored potential explanations. Design: We conducted a secondary analysis of a cross-sectional study of individuals with T2D. Symptomatic knee OA was defined using NICE criteria (age ≥45 years, activity-related knee pain, morning stiffness ≤30 min; no inflammatory arthritis). HRQoL (EQ-VAS, 0-100), sleep disturbance (PROMIS Sleep Disturbance 4a), depressed symptoms (PROMIS Depression 8b), fatigue (PROMIS Fatigue 4a), and walking limitation (Health Assessment Questionnaire) were assessed via questionnaire. Linear regression modeled associations between knee OA and HRQoL, adjusting for age, gender, BMI, education, and comorbidities. The explanatory effects of sleep, mood, and mobility were assessed via further sequential adjustment. Results: We included 341 participants: mean age 66.4 years, 51.9 % female, 29.0 % had knee OA. Participants with T2D and knee OA reported lower HRQoL, greater sleep disturbance, fatigue, depressive symptoms, and walking limitations than those without knee OA. Knee OA was associated with lower HRQoL (β = -11.96; 95 % CI: -16.59 to -7.32) in the unadjusted analysis. Adjustment for confounders partially attenuated this effect (β = -8.33; 95 % CI: -12.72 to -3.94). Further adjustment for sleep, mood, and walking limitations fully attenuated the association. Conclusion: Symptomatic knee OA is strongly associated with impaired HRQoL in T2D, explained by sleep disturbance, low mood, and mobility limitation. Integrated care addressing OA may improve quality of life in this population.