Background Several epidemiological studies have shown the existence of diabetes (type II) - associated osteoarthritis (T2D-associated OA). Currently there is a lack of data about special features of this OA phenotype.
Objectives To explore the proinflammatory serum cytokine levels and the clinical features in patients with knee OA and T2D and compare with patients with knee OA without T2D.
Methods Patients (n=78) were divided into two groups. Group 1 (n=52) had bilateral knee OA according to ACR criteria and T2D diagnosed one year before the start of joint disease. Group 2 (n=26) had bilateral knee OA according to ACR criteria without T2D. We assessed serum cytokine levels (IL-6, IL-18) using ELISA. Pain, general health, stiffness, physical functions, quality of life (QoL) and mental health disorders were measured by visual analog scale (VAS),Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee injury and Osteoarthritis Outcome Score (KOOS), short form 36 (SF-36), patient health questionnaire-9 (PHQ-9). Statistical data are presented as median and 25/75 percentiles. We used U-Mann-Whitney test to detect differences between groups. Correlation was assessed using Spearman correlation coefficient (rs).
Results Median age of group 1 (n=52) were 63 (interquartile range (IQR)): 58.25-69) 80.7% were women. At the group 2 (n=26) median ages were 66 (IQR: 54-70) 84.6% were women. Serum cytokine levels of IL-6 and IL-18 were significantly higher in patients of group 1 than the group 2 (p=0.0006 and p=0.0012 respectively). Statistically significant differences between two groups were found in such scales and indices as VAS, WOMAC, KOOS and SF-36 (certain data performed in Table). Also, mental health disorders in groups had statistically significant differences (SF-36 MH p=0.0137, PHQ-9 p=0.0424). Significant correlation was found between serum cytokines concentrations (IL-6 and IL-18) and most parameters of KOOS, SF-36 in both groups.
Conclusions According to this study results, plasma cytokine concentrations were elevated and observed high intensity of pain, significant impairment of physical functions, mental health and QoL in T2D-associated OA patients. Also this study suggests that serum cytokines concentrations are linked with the severity of knee T2D-associated OA. A positive association between IL-6, IL-18 and T2D-associated OA may assume participation of this proinflammatory factors in the pathogenesis of this OA phenotype. These data should be verified by larger studies.
Disclosure of Interest : None declared