Relation between FRAX index and ACPA serum level in premenopausal rheumatoid arthritis patients

Abstract

Rheumatoid arthritis (RA) is the most common form of inflammatory arthritis in adults and is characterized by synovial inflammation and hyperplasia, autoantibody production: rheumatoid factor (RF) and anti-citrullinated protein antibody (ACPA), cartilage and bone destruction, and systemic features, including cardiovascular, pulmonary, psychological, and skeletal disorders. Fracture Risk Assessment Tool (FRAX) is a computer-based algorithm developed by the World Health Organization (WHO) Collaborating Centre for metabolic bone diseases and first released in 2008. The outputs of FRAX are the 10-year probability of a major osteoporotic fracture (hip, spine, humerus or wrist fracture) and the 10-year probability of hip fracture. The study included 25 premenopausal RA patients and 20 healthy subjects. The serum ACPA level was assessed by ELISA technique, RF using Rose Waaler test in IU/mL was measured as well. BMD in (g/cm 2 ) has been measured for all subjects enrolled in the study by a Lunar Prodigy Advanced DEXA scanner system and were carried out by the same technician. FRAX index was calculated for all members in both groups by using online FRAX calculator. Femoral neck BMD was added to enhance fracture risk prediction. The range of ACPA in the patients group ranged between 11.40–525.0 U/mL. Eighty percent of our patients were ACPA positive. While RF range was from 8.30 to 648.0 IU/mL. Strong statistically significant difference between both groups was found where FRAX index was significantly higher in patients group compared to control group as regards major osteoporotic and hip fractures ( P < 0.001). Serum ACPA and RF level showed insignificant correlation with FRAX index in premenopausal RA patients. FRAX index was found to be high in RA patients but it was not correlated to ACPA nor RF serum level.