Determining knowledge of accurate population prevalence of rheumatic diseases is important in assessing the burden of the illness in the community and provides a basis for healthcare provision, policy, and workforce planning. The use of self-report is an integral part of determining the population prevalence of many chronic and non-registry–based diseases. Indeed, this is often the only way to obtain prevalence information for these conditions because definitive diagnostic tests may not exist or may be impractical to administer across a large number of people. Both prevalent and incident disease can be determined in this manner; however, there is evidence of a difference in the sensitivity of self-reporting prevalent and incident disease, and differences according to the disease examined. Oksanen, et al1 determined that the identification of true negatives was equally high for both prevalent and incident disease when compared with national registry data, but the sensitivity of incident ranged from 55% to 63% compared with prevalent disease (78%–96%) for hypertension, diabetes, asthma, coronary heart disease, and rheumatoid arthritis (RA). Both prevalent and incident self-reported diabetes have also been shown over time by Schneider, et al2 to have 84%–97% specificity and 55%–80% sensitivity when compared with reference definitions (glucose and medication criteria).
The prevalence and incidence of inflammatory rheumatic conditions, in particular, is also often only measured using self-reported information, and because of the heterogeneity of diseases within this group, the information may or may not be supplemented and validated by medication data or other relevant clinical tests. A combination of self-report and other forms of …
Address correspondence to Dr. C.L. Hill, The Queen Elizabeth Hospital, Rheumatology, 28 Woodville Road, Woodville, South Australia 5011, Australia. E-mail: Catherine.Hill{at}sa.gov.au