Background-There has been great interest in optimizing prophylaxis against venous thromboembolism (VTE) in the hospital setting. However, data from earlier studies suggest that the majority of VTE events occur in the outpatient setting. The purpose of this observational study was to describe the frequency of VTE events occurring in the outpatient setting, characterize the prevalence of previously identified risk factors for VTE, and to identify prior utilization of VTE prophylaxis. Methods-The medical records of residents from the Worcester (MA) metropolitan area diagnosed with ICD-9 codes consistent with possible VTE during 1999, 2001, and 2003 were independently validated and reviewed by trained abstractors. Results-A total of 1,897 subjects had a confirmed episode of VTE. Approximately 74% of patients developed VTE in the outpatient setting-a substantial proportion of these patients had undergone surgery (23%) or hospitalization (37%) in the preceding 3 months. Among these patients, more than 50% experienced VTE within one month of the preceding hospital encounter. Other major risk factors for VTE in the outpatient setting included active malignancy (29%) or prior VTE (20%). Among patients with a recent hospitalization who subsequently developed VTE, less than 50% had received anticoagulant prophylaxis for VTE during that visit. Conclusions-More VTE events were diagnosed in the 3 months following hospitalization than during hospitalization. Efforts to improve in-hospital utilization of VTE prophylaxis may help decrease the incidence of outpatient VTE. However, given shortening lengths of hospital stay, studies of extended VTE prophylaxis following hospital discharge are warranted.

Background While there have been advances in prophylaxis and management of venous thromboembolism (VTE), there are a dearth of data from the perspective of a community-wide study, on the epidemiology, management, and outcomes of patients with a first episode of deep vein thrombosis (DVT) or pulmonary embolism (PE). Objectives The purpose of this population-based observational study was to describe trends in the incidence rates, clinical profile, management, and outcomes for patients with VTE. Methods The medical records of Worcester (MA) metropolitan area residents with ICD-9 codes consistent with possible VTE during 1999, 2001, and 2003 were independently validated and reviewed by trained abstractors. Results A total of 1,567 persons with first-time VTE were identified. Incidence rates (per 100,000) of VTE were stable between 1999 (109) and 2003 (117). A considerable proportion of patients treated for VTE had events of unclear clinical significance (e.g., isolated calf DVT, unconfirmed “possible” PE). By 2003, low-molecular-weight heparin was increasingly utilized as acute therapy and more than 25% of patients with VTE were managed as outpatients. Cumulative rates of recurrent VTE and major bleeding following initial VTE were high (~16% and 12%, respectively, mean follow-up 1,216 days) and did not change significantly between 1999 and 2003. Conclusions Our data suggest that while the incidence rates of VTE remain high, and outcomes suboptimal, there have been marked changes in its management. Whether these changes will result in future declines in VTE incidence and/or improved outcomes in the community setting will require further surveillance.

Background: Although increasingly recognized as a major clinical problem, most reported estimates of the attack rates of venous thromboembolism (VTE) are based on studies enrolling patients more than a decade ago. Given changes in patient characteristics, risk factor profiles, and prophylaxis strategies over time, more current estimates are needed if we are to better target high-risk patients and allocate limited health care resources. The purpose of this study was to describe crude, as well as age and gender adjusted, attack rates of deep vein thrombosis (DVT) and pulmonary embolism (PE) in residents of the Worcester Statistical Metropolitan Area (SMSA) during the year 1999. Methods: The medical records of all male and female residents from the Worcester SMSA (2000 census = 478,000) diagnosed with ICD-9 codes consistent with possible DVT and/or PE at all 11 greater Worcester hospital during 1999 were reviewed by trained data abstractors. Characterization of each case of VTE was classified as definite, probable, or possible using prespecified criteria. For purposes of this analysis we approximated attack rates for the total Worcester SMSA population. However, for several specific analyses we have excluded 15 cases of validated VTE occurring in patients < 25 years of age. Age and sex-specific attack rates were calculated in a standard manner. Attack estimates were based on 2000 Massachusetts Census data for the Worcester SMSA which reported 287,631 residents 25 years of age or older. Results: There were a total of 590 recognized episodes of VTE in residents of the Worcester SMSA yielding an approximate attack rate of 123/100,000 population. Approximately one quarter of patients developed VTE during hospitalization for another indication while the remaining three quarters presented to the hospital with VTE. Excluding 15 cases of VTE occurring in patients < 25 years of age yields an attack rate of 200 per 100,000 population (95% C.I. 184, 216). Our study sample included 420 cases of isolated DVT (146/100,000 population), 140 cases of PE with or without DVT (49/100,000 population), and 74 cases of recurrent DVT (26/100,000 population). Overall, attack rates of DVT and PE for females were similar to those of men (DVT 152/100,000 vs 139/100,000; PE 51/100,000 vs 45/100,000). However attack rates in females age 75 years and older were significantly greater than those in men of the same age. The age and specific attack rates of clinically recognized VTE are shown in Figure 1. Conclusions: The annual overall attack rate of VTE in this community based study was slightly higher than that reported in the initial Worcester DVT study of 1985/1986 (107/100,000). In addition, if one excludes the small number of cases of VTE occurring in the young, attack rates/100,000 are almost doubled and increase rapidly with age particularly in women. These data have important implications for targeting of VTE prophylaxis and utilization of health care resources. Attack rate of clinical recognized VTE per 100,000 population: The Worcester Venous Thromboembolism Study 1999 Attack rate of clinical recognized VTE per 100,000 population: The Worcester Venous Thromboembolism Study 1999

These data provide insights into recent incidence and attack rates, changing patient profiles, management strategies, and subsequent outcomes in patients with venous thromboembolism. The underutilization of prophylaxis before venous thromboembolism, and relatively high 30-day recurrence rates, suggest a continued need for the improvement of venous thromboembolism prophylaxis and management in the community.