Background A number of factors influence development and progression of osteoarthritis (OA), including comorbid diseases. Such factors as obesity, impaired glucose tolerance, raised blood glucose level can affect clinical processes and also have similar mechanisms of immunopathogenesis with OA.
Objectives To explore the symptoms and the proinflammatory serum cytokine levels in patients with knee OA and obesity, metabolic syndrome (MS) and type 2 diabetes mellitus (T2DM) and to estimate association between clinical and immunological features.
Methods A study was performed on 128 persons with bilateral knee OA according to the ACR criteria who were divided into four groups. Group 1 (n=17) had obesity, group 2 (n=17) had MS, group 3 (n=56) had T2DM and group 4 (n=38) had only knee OA without comorbid diseases. All patients were comparable by age, sex and duration of OA. We assessed serum cytokine levels (IL-1b, IL-6, IL-10, IL-18), NO including adipokines such as adiponectin and leptin using ELISA. Intensity of pain, general health, stiffness, physical functions were measured by visual analog scale (VAS),Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee injury and Osteoarthritis Outcome Score – (KOOS) and with short form 36 (SF-36). U-Mann-Whitney test was applied to detect differences between groups. Correlation was assessed using Spearman correlation coefficient (rs).
Results In the course of the comparative analysis of the groups of OA patients and concomitant diseases with a group of OA patients without comorbidity there were found many statistically significant differences in such scales and indexes as VAS, WOMAC, KOOS, SF-36. Patients with OA and obesity are characterized by the prevalence of symptoms OA of KOOS scale (median (Me) 61.1; interquartile range (IQR) 55.5–70.8; p<0.001). Patients from group 2 (MS) and 3 (T2DM) were significant worse parameters of general health and high levels of pain, morning stiffness and functional disoders of the knees. Differences in serum cytokine levels were found in patients with OA and T2DM (IL-6 p=0.0018; IL-18 p=0.0006; NO p<0.001). Patients with OA and obesity had high leptin level (p=0.03). Group 3 with OA and T2DM had significant differences in leptin (p=0.0002). Correlation analysis identified relationships between clinical parameters and cytokines in OA patients with obesity and T2DM. Some data is presented (Table).
Conclusions According to the study, patients with obesity, MS and T2DM have special clinical and laboratory features of progression of OA. Such immunological parameters as serum cytokine concentrations may also be linked with symptoms of OA in patients with aforecited comorbidity. These data should be verified by larger studies.
Van Dijk G.M. et al. Comorbidity, limitations in activities and pain in patients with osteoarthritis of the hip or knee. BMC Musculoskel Dis 2008
Pottie P. et al. Obesity and osteoarthritis: more complex than predicted!. Annals of the rheumatic diseases 2006
Zhuo Q. et al. Metabolic syndrome meets osteoarthritis. Nature Reviews Rheumatology 2012
Louati K. et al. Association between diabetes mellitus and osteoarthritis: systematic literature review and meta-analysis. RMD open 2015
Disclosure of Interest None declared