This thesis aims to assess the differences and similarities between autoantibody-positive and autoantibody-negative RA from the start of complaints to the end of the disease. The described research... Show moreThis thesis aims to assess the differences and similarities between autoantibody-positive and autoantibody-negative RA from the start of complaints to the end of the disease. The described research was performed with the ultimate goal to clarify whether autoantibody-negative and autoantibody-positive RA are distinct diseases that require different diagnoses and treatment. Show less
Studies in this thesis were performed in a secondary care cohort of patients with hand osteoarthritis. Several factors were investigated for their association with disease status and disease... Show moreStudies in this thesis were performed in a secondary care cohort of patients with hand osteoarthritis. Several factors were investigated for their association with disease status and disease progression after two years. These factors included comorbidity, illness perceptions and MRI-defined inflammatory features such as bone marrow lesions, synovitis and joint effusion. In the MRI studies we found that these MRI-features have a clinically relevant role for their association with pain (at the same moment and after two years) and progression of radiographic damage after two years. In the second part of this thesis we evaluated the clinimetric properties of two new instruments: self-reported painful joint count and semi-automatic joint space width measurements. Show less
Pulmonary embolism is traditionally, since autopsy studies by Virchow in the mid 1800s, thought to originate from embolization of a deep-vein thrombosis, resulting in two clinical manifestations of... Show morePulmonary embolism is traditionally, since autopsy studies by Virchow in the mid 1800s, thought to originate from embolization of a deep-vein thrombosis, resulting in two clinical manifestations of one disease: venous thrombosis. The incidence of deep-vein thrombosis in the population is twice as high as the incidence of pulmonary embolism, i.e. 1 per 1000 and 0.5 per 1000 person-years respectively. The aim of this thesis was to assess whether pulmonary embolism and deep-vein thrombosis are always the same disease or not, and to answer this question with regard to etiology (genetic and acquired risk factors) and anatomical distribution of thrombi in the veins. We studied this question in two populations: the PEDLAR study and the MEGA case-control study. In the PEDLAR study we assessed the origin of pulmonary embolism using a total body Magnetic Resonance Direct Thrombus Imaging technique. We proposed several mecha nisms for the absence of deep-vein thrombi in more than half of the patients with pulmonary embolism. In addition, we investigated the effect of aging on venous valve thickness. This was performed in an ultrasonography study, with participants from 20 to 80 years old (the aging venous valves study). We hypothesized that part of the increasing incidence in venous thrombosis with age can be explained by increasing valve thickness. Show less
