This study investigated for the first time the impact of physical activity levels on hospital admissions and length of hospitalisation over one year in patients with RA. Our results revealed that disease activity and physical activity are both significant predictors of these two variables.
Studies with RA patients reveal that, due to the high prevalence of co-morbidities , patients feel uncertain about the outcomes of their disease and hence, admission to the hospital may have deleterious effects, particularly in patients with early disease . Hospitalisation may lead to negative self-esteem and loss of privacy  and may have a significant, lasting adverse impact on the quality of life of the patient. It also associates with very high costs to the health system. Hence, it is important to identify strategies that may improve overall management and reduce hospitalisation in this patient group.
To this end, improved pharmacological therapy for RA, particularly after the introduction of biological medication with anti-TNFa agents, has significantly improved disease management and appears to reduce hospital admissions and lengths of stay , but it also increased direct drug costs [2, 4, 16]. A very important factor that may considerably affect RA management is lifestyle change with increased involvement in exercise and/or physical activity. The results from the present study may also suggest beneficial effects of physical activity, both to the individual patients and the healthcare system, by a reduction of the number and length of hospitalisation. However, the cross sectional design adopted herein cannot prove definite causality and it is likely that the number of hospital admissions as well as the length of hospitalisation is mediated by many different factors, which have to be investigated in relevant trials. Our suggestion for a potential association of increased physical activity with reduced admission rates lies in robust research evidence which have consistently shown that regular exercise and physical activity significantly improve RA patient outcomes (by promoting beneficial body composition changes and reducing fatigue), inhibit progression of the disease (by reducing inflammation and increasing muscle mass and bone mineral density), and lead to significantly better cardiovascular health and reduced risk to develop cardiovascular disease [8, 17–19].
Previous studies have shown that disease activity significantly influences direct and indirect RA costs . We found that disease activity and disability may also impact upon future admission rates. In fact, we have previously demonstrated that effective treatment enables patients to engage with more active lifestyles and better diet . The combination of increased physical activity and effective medication, therefore, may not only inhibit disease progression thereby improving quality of life, but it may also reduce costs by reducing the need for surgery, and admission to acute and extended care hospitalisation, as well as social service utilization.
The observed physical activity levels herein are significantly lower compared to patients with other chronic diseases, including obesity , cancer  and osteoarthritis . More importantly, only a fifth (19%) of the total wide-range (in terms of age and disease duration) RA population studied, achieved the recommended levels of physical activity, a significantly reduced number compared to the normal population (approximately 35%) . More importantly, this 19% corresponds mainly to the younger RA patients. Although it is well-established that aerobic capacity is significantly compromised in the RA population , our data also demonstrate that RA patients do not achieve the physical activity levels required to minimise their risk for developing cardiovascular disease, inhibit age-related muscle loss, improve quality of life and well-being. Improvement in these parameters is crucial as the prevalence of cardiovascular disease and cachexia is higher in RA than in the normal population , partly due to the presence of traditional risk factors [25–28] but also due to the metabolic and vascular effects of persistent high-grade inflammation [29, 30]. Moreover, physical ability may be worse due to disease-related processes, although it may be partly improved by effective treatment strategies . Participation in structured exercise programmes is necessary to reversing these phenomena, but this requires patients to be in a controlled environment. Involvement in increased physical activity such as leisure walking, however, is different and requires a different level of determination and commitment given the lack of immediate advice that is available in structured exercise programmes by the instructors. Thus, improving determination to keep active should be a future focus of intervention strategies in order to improve health and quality of life in this population.
One of the important limitations of the present study is the adopted cross-sectional design which is not sufficient to prove a cause-and-effect relationship between the parameters studied. As such, it cannot be ensured that physical activity may have a profound effect on RA, which in turn will result in reduced admission rates or if, in contrast, patients who exercise more have lower disease activity and severity and, hence, they are not admitted to the hospital frequently. Ensuring quality primary care has been recognised as a crucial component in keeping patients with chronic disease out of hospital . It has also been suggested that patients from disadvantaged areas have a higher and prolonged rate of admission . We were not able to standardise for these factors in the present study; all patients came from a relatively distinct geographical area of the UK, which, however, contains a diverse socioeconomic strata and variable access and quality of primary care services. We also did not assess directly either the effects of hospitalisation to quality of life, or the costs incurred as a result of it. On the other hand, the originality of the question, use of validated measures in a consistent fashion, as well as possible mediation or moderation effects, represent important strengths of the study. Clearly, several of the associations found here need to be confirmed in future prospective studies, designed specifically for the purpose.