Background Obesity appears to play a role in the development of knee osteoarthritis (OA) and has been shown to influence pain and disease progression. Leptin is an adipokine involved in body weight regulation and known to show inflammatory effects in high concentrations and has also been implicated in OA physiopathology and pain.
Objectives To evaluate the correlation between different body weight measurements (body mass index (BMI), waist-to-hip ratio (WTHr) and percentage of body fat (%BF)) and synovial fluid leptin in patients with knee osteoarthritis and synovial effusion.
Methods Cross-sectional study including patients aged 50 years or more with symptomatic knee OA and joint effusion, Kellgren-Lawrence II-III. Demographics, disease duration and body mass index (BMI), waist-to-hip radio (WTHr) and percentage of body fat (%BF) were assessed. Percentage of body fat was determined by bio-electrical impedance. Intraarticular leptin levels were analyzed using a Human leptin ELISA kit (Biocompare, California, USA). All patients were evaluated in a fasting condition and approximately at the same time of the day.
Results Seventy consecutive female patients with symptomatic knee OA and Kellgren-Lawrence II-III were included, age 65±7.8 (50-79) years, disease duration of symptoms 66±49.5 mo (12-200). Mean BMI was 31.5±5.1 kg, mean WTHr 0.94±0.082 and mean %BF 42.34±5.11%. Mean levels of leptin in synovial fluid were 76.76±38.66 ng/mL. BMI and %BF showed similar moderate positive correlation with synovial fluid levels of leptin (r=0.4626 and r=0.4610, respectively), whereas no correlation was found between WTHr and leptin synovial levels (r=0.059).
Conclusions Both BMI and the percentage of body fat showed a moderate positive correlation with synovial levels of leptin in a similar degree. Thus, synovial leptin may be associated in a similar way with a measure of relative weight as BMI or with a measure reflecting relative fat content.
Disclosure of Interest None declared