Brazil Patient Knowledge Questionnaire (PKQ) and evaluation of disease-specific knowledge in patients with rheumatoid arthritis

To create a Brazilian version of the Patient Knowledge Questionnaire--PKQ, an instrument for measuring the knowledge of patients with rheumatoid arthritis (RA) as regards their disease, and through the use of this instrument, also measure the knowledge of RA patients from reference hospitals in the city of São Paulo. Two teachers of English translated the PKQ into Portuguese in order to obtain a single version, which was then translated back into English to evaluate its equivalence to the original version (back translation). The final version in Portuguese was applied to 20 patients with RA for adaptation to cultural issues, and questions not understood by 20% or more patients were subsequently modified. Inter- and intraobserver reliability and the constructive validity of the PKQ were tested. The questionnaire was then applied to 100 RA patients, selected in four outpatient clinics at reference hospitals in the city of São Paulo. Three of the PKQ questions were modified to adapt to cultural issues. Intraclass correlation coefficients used for the reliability and validity of the PKQ were between were between 0.62 and 0.94, therefore, statistically significant (p< 0.05). The mean PKQ score was 12.96 and the mean test application time was 10.3 minutes, for the 100 patients assessed. The lowest scores were observed in the domains of medications and joint protection/energy conservation. PKQ scores showed a positive correlation with the level of education (r=0.40) and a negative correlation with the patients' age (r= -0.32) and with HAQ (r= -0.28). The Brazilian version of the PKQ that was created and proved to be a reliable and valid instrument. Patients' knowledge of RA is poor, particularly in the domains regarding medications and joint protection/energy conservation.