Objective: Self-reported diagnoses of rheumatic conditions are frequently used in epidemiological and clinical research. Our objectives were to examine the validity of patient self-reported rheumatoid arthritis (RA); and to assess the predictive value of symptoms, health status measures, and demographic variables with respect to the actual diagnosis.
Methods: A postal survey was performed in Oslo of 10,000 randomly selected individuals between 20 and 79 years of age. Respondents reported musculoskeletal pain, stiffness, rheumatic diagnoses, disability, and mental distress. The patients reporting RA (either according to patient or doctor) were selected for further examination.
Results: Of 5886 respondents (3670 with musculoskeletal pain or stiffness) 158 patients (2.7%) reported having RA diagnosed by doctor (n = 107) and/or according to their own opinion (n = 142). RA was confirmed by clinical examination in 35 of these 158 individuals (22%, CI 16,29). Patients with perceived and actual RA differed regarding self-reported presence of swollen joints and disability score. Multivariate analyses failed to identify a set of useful predictors for the correct diagnosis.
Conclusion: Patient self-reported diagnosis of RA is unreliable for research or clinical purposes.