Rheumatic diseases, irrespective of etiology and clinical course, influence different areas of a patient's life. Adapting to disability and limitations caused by an illness is very difficult for many patients. The main goal of a therapeutic procedure should be improvement of health-related quality of life (QoL).
Evaluation of the factors that influence the QoL that are conditioned by the state of health of patients with osteoarthritis (OA) and rheumatoid arthritis (RA).
The study group consisted of 198 patients diagnosed with OA, according to the American College of Rheumatology criteria (1988), and 100 patients diagnosed with RA, according to the American College of Rheumatology criteria (2010). A diagnostic survey using visual analog scale of pain, health assessment questionnaire disability index, and 36-item short form health survey were used in this study.
The average age of patients with OA was 59.16 (±15.87) years and patients with RA was 55.22 (±14.87) years. The average duration of illness examined for OA was 5.5 (±4.32) years, whereas for RA, it was slightly more at 6.8 (±5.21) years. Overall the QoL in both study groups was of medium level. Among patients with OA and RA, lower evaluation of QoL was mainly affected by age (OA - physical sphere [PCS] 
Patients with OA, despite their average older age, had a higher evaluated QoL than patients with RA. Overall QoL in terms of mental functioning in both rheumatic diseases was assessed at a higher level than in the area of physical functioning.