Introduction: Substantial effort has been devoted for devising effective and safe interventions to reduce preventable hospital admissions in chronic disease patients. In rheumatoid arthritis (RA), identifying risk factors for admission has important health policy implications, but knowledge of which factors cause or prevent hospital admissions is currently lacking. We hypothesised that disease activity/severity and physical activity are major predictors for the need of hospitalisation in patients with RA.Methods: A total of 244 RA patients were assessed for: physical activity (International Physical Activity Questionnaire), RA activity (C-reactive protein: CRP; disease activity score: DAS28) and disability (Health Assessment Questionnaire: HAQ). The number of hospital admissions and length of hospitalisation within a year from baseline assessment were collected prospectively.Results: Disease activity and disability as well as levels of overall and vigorous physical activity levels correlated significantly with both the number of admissions and length of hospitalisation (P <0.05); regression analyses revealed that only disease activity (DAS28) and physical activity were significant independent predictors of numbers of hospital admissions (DAS28: (exp(B) = 1.795, P = 0.002 and physical activity: (exp(B) = 0.999, P = 0.046)) and length of hospitalisation (DAS28: (exp(B) = 1.795, P = 0.002 and physical activity: (exp(B) = 0.999, P = 0.046). Sub-analysis of the data demonstrated that only 19% (n = 49) of patients engaged in recommended levels of physical activity.Conclusions: This study provides evidence that physical activity along with disease activity are important predictors of the number of hospital admissions and length of hospitalisation in RA. The combination of lifestyle changes, particularly increased physical activity along with effective pharmacological therapy may improve multiple health outcomes as well as cost of care for RA patients. © 2011 Metsios et al.; licensee BioMed Central Ltd.