All other diseases that coexist with a disease of interest are called comorbidities. Comorbidities in inflammatory rheumatic diseases may be associated with persistent inflammatory activity or disease-related organ damage, or may be related to medications. Lifestyle choices such as smoking or physical inactivity contribute to comorbidity. Patients with rheumatic diseases meet health professionals regularly and are more often tested for osteoporosis or cholesterol levels than individuals without rheumatic disease, which may contribute to a higher prevalence of some comorbidities. Comorbidities can also be unrelated to rheumatic diseases or their treatments.
Poor physical function and low muscle strength are significant predictors of mortality in rheumatic diseases, other chronic diseases, ageing individuals, and the general population. Poor physical function predicts earlier mortality in diseased and normal populations at levels of significance similar to or greater than most known biomedical predictors such as laboratory tests. The data support recommendations for regular exercise in all individuals whether or not they have a disease, to promote health and longevity.
Disclosure of Interest None declared