Course of patient-reported health outcomes in rheumatoid arthritis: comparison of longitudinal and cross-sectional approaches.

Abstract

To describe health outcomes reported by patients with rheumatoid arthritis (RA), i.e., pain, disability and health-related quality of life, as a function of disease duration in a longitudinal approach, and to compare the course of patient-reported health outcomes by a longitudinal versus a cross-sectional approach. Data were collected with 4 series of questionnaires between 1997 and 2002 among patients with RA (maximum number = 882) of varying disease duration. The course of patient-reported health outcomes as a function of disease duration was evaluated using both longitudinal data and cross-sectional data of the first series. The course of RA shows a different pattern for various health outcomes. We observed similar trends in health outcomes in this large patient sample using the longitudinal and the cross-sectional approach. Although longterm consequences of RA are preferably assessed in longer duration followup studies, cross-sectional studies, including patients with a broad range of disease durations, seem to provide fairly reliable estimates of the course of health outcomes.