Clinical epidemiology

The research within our LUMC departments is conducted within departmental research programmes. The research programme below is embedded within the department of Clinical Epidemiology.

Aim and focus

Clinical epidemiology consists of the application of general epidemiologic principles in clinical research. The department has two aims: to apply these principles to particular research questions, and to study the methods themselves. Generally, the research concerns questions which necessitate a numerical approach, and in which the patient is the unit of observation. Specifically, the programme of the department focuses on aetiology and prognosis in several fields, e.g., haemostasis and thrombosis, renal dialysis, fertility, arthrosis.

Position in international context

Much of the research is performed in international collaborations, amongst others with universities in Milan, Seattle, Tromsø, Burlington (Vermont), Tehran, Aarhus and Copenhagen, with frequent exchanges of personnel and affiliate appointments.

Content / highlights / achievements

The research themes, the current studies and their principal investigators, are: 

  • Venous thrombosis (LETS, MEGA, VTE, AT-AGE, PODCAST): Dr S.C. Cannegieter, Dr A. van Hylckama Vlieg, Dr W.M. Lijfering, Prof. dr F.R. Rosendaal 
  • Arterial thrombosis (SMILE, RATIO): Prof. dr F.R. Rosendaal, Prof. dr A. Algra 
  • Methodology: Dr S. le Cessie, Dr O.M. Dekkers, Prof. dr J.P. Vandenbroucke
  • Renal dialysis (NECOSAD, PREPARE, EQUAL): Dr M. van Diepen, Prof. dr F.W. Dekker 
  • Blood management: Prof. dr J.G. van der Bom 
  • Osteoarthritis (GARP, HOSTAS): Prof. dr M. Kloppenburg, Prof. dr F.R. Rosendaal 
  • Metabolic syndrome (NEO): Dr R. de Mutsert, Dr D. Mook, Prof. dr F.R. Rosendaal 

In the area of thrombosis research, the Leiden centre has initiated the introduction of large, properly designed controlled studies, such as the first case-control study into the aetiology of venous thrombosis (Leiden Thrombophilia Study, LETS), in the early 1990s. This single study has been instrumental in the identification of a series of new risk factors for venous thrombosis (factor V Leiden, prothrombin 20210A, high levels of FVIII, FIX, FXI, TAFI), published in over 60 papers. Currently, there are several studies into the aetiology of first thrombosis and recurrence, with a broad array of foci: genetic risk factors, global coagulation assays, endocrine factors, the elderly, imaging and the interaction of risk factors. In the field of arterial thrombosis studies focus on genetics, contact activation and aspirin resistance. Since 1997, over 2000 new patients on renal dialysis have been included in a national prospective cohort study (NECOSAD), with frequent data collection, with a database and biobank at the Leiden centre, which has so far led to over 50 papers. In collaboration with Sanquin, aspects of blood transfusions are investigated, in collaboration with several clinical departments (eg, Obstetrics). The department participates in national studies of the impact of bleeding disorders such as haemophilia and Von Willebrand disease, and in studies in their optimal treatment, as well as of acquired bleeding (eg, postpartum haemorrhage). The department coordinates a large cohort study in overweight individuals (NEO study, see in which 10 LUMC departments participate and which is growing is a focus of research, attracting many students and PhD-fellows. Publications During the last five years (2008-2013) we consistently published in the major medical journals (well over full 500 papers), with 43 full papers in the highest impact journals (NEJM 3, Lancet 3, JAMA 4, Nat Genet 1, Lancet Neurol 1, BMJ 2, Ann Intern Med 2, Circulation 5, Plos Med 3, Blood 19). Over the previous audit period (2003-2007), these figures were 400 full papers and 30 in the highest impact journals.

Future themes

In the coming years, existing research lines will be continued and expanded. A major focus will be the NEO study in which we included 6700 predominantly overweight and obese individuals. Inclusion was completed in 2012, with extensive and sophisticated baseline measurements, including MRI, ultrasound, standardised meal challenge, heart rhythm variation, indirect calorimetry. It is our aim to continue collaborative research with clinical departments and research laboratories. In addition, we will strengthen our collaboration with other methodological departments (e.g. Medical Statistics, Decision Making) to streamline education and consultative research within the LUMC, and to benefit from eachother’s distinct expertise.

Cohesion within LUMC

Clinical research is of major importance to the LUMC, and clinical epidemiology is an integral part of such research. There is a strong network of collaboration with other departments, in some instances involving comprehensive research programmes and projects with joint PhD fellows. These include Thrombosis and Hemostasis, Rheumatology, Cardiology, Endocrinology, Pulmonology, Nephrology, Radiology, Public Health and Primary Care, Obstetrics, Immunohaematology and Blood bank (IHB), Neonatology en Thoracic surgery. Many of the staff members have joint appointments (Thrombosis and Hemostasis, Rheumatology, Endocrinology, Orthopedics, Medical Statistics, Sanquin). The NEO study is a resource that is a fully collaborative joint enterprise.