VENOUS THROMBOEMBOLISM IN SOUTHERN SWEDEN EPIDEMIOLOGY AND RISK FACTORS

Abstract: Despite the fact that venous thromboembolism (VTE) is an important cause of morbidity and mortality there is still insufficient information on VTE risk factors and patient characteristics in the general population. Previously published incidences of VTE (deep venous thrombosis [DVT] and pulmonary embolism [PE]) vary from 71 to 192 per 100,000 individuals per year. Incidences of DVT and PE have been estimated to 48-160 and 23-60 cases per 100,000 inhabitants per year, respectively. The aims of this thesis were to evaluate VTE epidemiology and risk factors in a population based total material from southern Sweden, to investigate potential relationships between the factor V Leiden (FVL)-mutation and hemoglobin (Hb) levels in VTE patients, to evaluate how socioeconomic status (SES) and concomitant diseases influence VTE risk during long time follow-up, and to investigate effects of low molecular weight heparin (LMWH) upon time of labor and bleeding in pregnant women with increased VTE risk. Incidences of VTE (lower extremity DVT, PE, and upper extremity DVT [UEDVT]) were all lower than in previous epidemiological studies. Hormone therapy, immobilization, previous surgery and concomitant malignancy were the most common acquired risk factors for VTE. Concomitant malignancy and thrombophilia were especially common in UEDVT, and mortality was high among UEDVT patients with malignancy at diagnosis. Female VTE patients < 50 years of age with the FVL-mutation had higher median Hb compared to female patients without the mutation. SES as reflected by lower income, single marital status, and lower level of education were all independently related to an increased VTE risk during prospective long time follow-up. Foreign ancestry, on the other hand, was related to lower VTE risk. LMWH treatment reduced the first stage of labour by 1 h and results in a significantly lower risk of prolonged first stage of labour among nulliparous pregnant women, but is also associated with an increased risk of prematurity and blood loss complications.