Rheumatoid factor and antibodies against citrullinated peptides in Moroccan patients with rheumatoid arthritis: association with disease parameters and quality of life

We aimed to evaluate the immunological status and its relationships with disease-related parameters of activity, severity and quality of life in Moroccan patients with rheumatoid arthritis (RA). Two hundred forty-five consecutive patients with RA were recruited. The following data were collected: demographic characteristics, disease duration (years), disease activity (evaluated by the disease activity score, DAS28), structural damage (evaluated by Sharp's method as modified by van der Heijde), functional disability (assessed by using the Moroccan version of the Health Assessment Questionnaire, HAQ) and quality of life (by using the Arabic version of the Medical Outcomes Study Short Form 36 Health Survey: the SF-36). Immunological status (rheumatoid factor rate, RF) and antibodies against citrullinated peptides rate (ACPAs) by the Elisa method were examined. ACPAs were detected in 75.1% of patients with a mean rate of 79.2 ± 43.8 UI. RF was detected in 80.8% of patients with a mean rate of 80.1 ± 50.6 UI. Patients with positive RF and ACPAs had higher disease activity, impaired functional ability, severe structural damage, more ocular symptoms and altered aspects of quality of life. In univariate analysis, higher levels of ACPAs were significantly correlated with the age at onset (r = 0.307), disease duration (r = 0.520), disease activity (DAS28) (r = 0.531), Sharp score (r = 0.431), and with the deterioration of all domains of SF-36 (for all p ≤ 0.01). RF levels were correlated with disease duration (r = 0.517), disease activity (r = 0.470), functional disability (r = 0.521), and the alteration of physical domains of SF-36 (for all p ≤ 0.01). In multivariate analysis, the main factors associated to ACPAs and RF levels were functional disability, structural damage and impaired QoL. Furthermore, using the SF-36 scores as dependent variables, the impairment of physical domains and the domain of vitality were significantly associated with ACPA levels while the decrease of the domain of physical function was associated with the level of RF. Our study suggests that the presence and the levels of ACPAs and RF in our RA patients are associated with more active disease, more severe joint damage, worst functional disability and altered aspects of quality of life.