Introduction: Rheumatoid arthritis is a chronic autoimmune inflammatory disease with progressive joint damage, leading to functional impairment of the locomotor system, including disability. Aim: The study aimed to examine the correlation between disease severity, pain intensity and functional capacity of patients with rheumatoid arthritis (RA). Material and methods: An observational, analytical, cross-sectional study that included 30 adult (≥ 18 years) subjects, who had been suffering from RA for two years or more. Data were collected by interviewing subjects, clinical examinations, using available medical documentation and specific questionnaires that are applied in RA. We determined the current disease activity (severity) using the Clinical Disease Activity Index, CDAI. To assess functional (in)capacity, we used the Health Assessment Questionnaire (HAQ). A Visual Analogue Scale (VAS) was used to assess the intensity of pain, which classifies the intensity of pain from 0 to 10. Descriptive statistical methods, methods for testing statistical hypotheses and methods for testing addiction were used for statistical data analysis. Statistical hypotheses were tested at a statistical significance level (alpha level) of 0.05. Results: Out of a total of 30 subjects, 13.3% were male and 86.7% were female. The average age of the subjects was 58.9 ± 8.0 years. In terms of occupation, the majority were retirees, and in terms of education, most subjects had a secondary vocational education. The average duration of the disease was 14 years. Our subjects most often had low and moderate disease activity (33.3% each). Regarding pain intensity, most participants experienced moderate pain (43.3%), the fewest had mild pain (26.7%), and 30.0% of participants reported severe pain. The VAS pain score median of all subjects was 5. The most common was a moderate to severe disturbance of functional ability (56.7%). It was found that there was a statistically significant association between pain intensity and functional disability (rs = 0.618; p = 0.001). There was also a statistically significant association between the degree of disease activity (CDAI) and functional disability (HAQ) (rs = 0,377; p = 0,040). No statistically significant correlation was shown between the duration of the disease and the degree of functional disability (rs = -0.037; p = 0.845). Conclusion: It is necessary to pay special attention to the treatment of pain in patients with RA, because its presence and intensity are closely related to the degree of functional disability.
