Does diabetes affect physical function and thigh muscle strength in subjects with or at risk for knee osteoarthritis? – A matched case-control study from the osteoarthritis initiative

Abstract-Text (inkl. Referenzen und Bildunterschriften)

Introduction: The prevalence of both osteoarthritis (OA) and diabetes mellitus (DM) increases with age. Understanding the interdependencies of both diseases and their effect on physical performance is necessary for designing targeted therapies, or to prevent incident OA in DM patients.

Purpose: To evaluate (a) self-reported measures of physical function (b) functional performance tests, and (c) thigh muscle strength in study participants with and without DM, selected from a public database (Osteoarthritis Initiative [OAI]) of subjects with or at risk for knee OA.

Methods: OAI participants with DM were matched 1:1 to control subjects without DM. Subjects with inflammatory arthritis, previous knee surgery or knee replacement were excluded. Self-reported measures of physical function included the WOMAC function score for the right knee, the Knee Outcomes in OA Survey Quality of Life (KOOS QOL) score, and the Physical Activity Scale for the Elderly (PASE). The times needed for completing the 5-repetition chair-stand-test (CST), 20m and 400m walk tests (WTs) were recorded. Isometric knee extensor and flexor strength were measured in the right knee using a dynamometer chair. Cross-sectional statistical comparison between subjects with and without DM was performed using paired t-tests. Cohen"s D was used as a measure of effect size.

Results: 152 matched pairs with/without DM with complete data were identified (Table 1). DM participants did not show significant differences of the KOOS QOL, PASE, WOMAC function, CST, knee extension force or flexion force compared with matched non-DM controls. However, DM participants exhibited an 8% longer 20m WT time, and a 9% longer 400m WT time compared with non-DM controls (Table 2).

Conclusion: Only the 20m and 400m walk tests differentiated between DM cases and non-DM controls. Despite the established impact of DM on OA pain, DM patients do not seem to suffer from clinically relevant limitations in physical function.