Glucose and its association with metabolic factors and biomarkers in patients experiencing symptomatic knee osteoarthritis : A cross-sectional study

Sammanfattning: Background Osteoarthritis (OA) is a long-term chronic disease that affects the joints and creates stiffness, pain and impaired movement. Knee osteoarthritis is the most common form of OA and affects all tissues of the joint, including bone, muscles, synovia, and cartilage. Previously, OA was accepted as only an age- or mechanical stress-related degenerative joint disease, but more recent studies suggest that OA is a heterogenous disease including inflammatory, hormonal and metabolic factors such as abdominal obesity (visceral fat), lipids (cholesterol, HDL, LDL and triglycerides) and glucose.    Aim The aim was to investigate the association of metabolic factors including fasting blood glucose, HbA1c, triglycerides, cholesterol, LDL, HDL, visceral fat, CRP and radiographic KOA in patients with symptomatic knee osteoarthritis. Methods Data were acquired from 91patients in the ages 30 – 63 experiencing symptomatic knee osteoarthritis. All subjects where divided into two groups depending on their level of fasting glucose, high versus low. Group I (n=26) had high glucose levels ≥5,6 mg/L and group II (n=65) had low glucose levels <5,6 mg/L.  Levels of HbA1c, lipids, visceral fat, CRP and radiographic KOA were then compared between the groups. Levels of fasting glucose, HbA1c and lipids (triglycerides, cholesterol, LDL, HDL) were analyzed by an accredited laboratory at the hospital of Halmstad by the department for labmedicine. CRP levels < 1 mg/L were manually analyzed with the sandwich ELISA method (enzyme-linked immunosorbent assay), which measures high-sensitive CRP (hsCRP) in serum. Visceral fat area was measured through bioelectrical impedance analysis (BIA) with InBody 770 and radiographs of the knees to obtain information about OA. Results There was a significant difference between the two groups in HbA1c, triglycerides, cholesterol and LDL p<0,05. Group I with high fasting glucose levels showed higher significant values of HbA1c, triglycerides, cholesterol and LDL than group II with low fasting glucose levels. 23% of all subjects met the requirement for metabolic syndrome according to IDF. Conclusion The findings in this study is in line with previous research and suggest that high glucose levels are associated with elevation of other metabolic factors in patients with knee osteoarthritis. However, there are several other interacting factors beyond the scope of this study, which may explain causalities. According to the findings in this study and previous research, obesity and metabolic syndrome could explain some of the connections between metabolic factors and knee osteoarthritis. Thus, further research is necessary to understand how all these metabolic factors are associated with osteoarthritis and obtain deeper knowledge about the pathogenesis and pathophysiology of the disease.