2578 Background: Thromboprophylaxis is the top challenge to patient safety practice in hospitals. Postoperative Deep vein thrombosis (DVT) and pulmonary embolism (PE) are the major cardiovascular killers in the surgical setting. In October 2008, Medicare designated DVT and PE occurring after total knee or hip replacement as ‘never events', and indicated that they will not pay the incremental cost to manage the complication and has made the hospital acquired DVT/PE unacceptable and serious. There are however, limited data on factors contributing to DVT/PE in-patients undergoing total knee or hip replacement. Aim: To ascertain nationwide health care utilization and associated co-morbidities in Total knee replacement (TKR) recipients who do or do not develop DVT/PE. Methods: We used the year 2007, National Inpatient Sample (NIS) to analyze the post operative occurrence of DVT/PE after TKR. We used an analysis similar to AHRQ's Patient Safety Indicator number – 12 (PSI 12) which is Postoperative Pulmonary Embolism or Deep Vein Thrombosis but restricted our analysis only to TKR. We intended to capture cases of postoperative venous thromboses and embolism - specifically, pulmonary embolism and deep venous thrombosis. For our analysis we separated TKR into 2 groups; one without DVT/PE and the other with DVT/PE. We analyzed all surgical discharges age 18 years and older with an ICD-9-CM code for an operating room procedure TKR (ICD-9 8154). From this we excluded those who have principal diagnosis of DVT/PE, as these patients are likely to have had PE/DVT present on admission and not because of TKR and also where a procedure for interruption of vena cava (IVC filter) (ICD-9 387) occurs before or on the same day as the first operating room procedure as these patients likely had DVT/PE even before TKR. We then created a subset from the first group, with discharges ICD-9-CM codes for deep vein thrombosis or pulmonary embolism in any secondary diagnosis field and thus defined the group of patients who developed DVT/PE after TKR. We used the following ICD-9 codes to represent DVT (ICD-9 codes 451.11, 451.19, 451.2, 451.81, 451.9, 453.40, 453.41, 453.42, 453.8, 453.9) and PE (ICD-9 codes 415.1–415.19). IBM SPSS Statistics 18 was used for data mining and analysis. Result: In the year 2007, there were 550,770 discharges with a procedure for TKR. After excluding primary diagnosis of DVT/PE and IVC filter, we had 550228 as our working number. Of these, 5454 discharges had a secondary diagnosis of DVT/PE (Rate - 10 new cases per 1000 TKR procedures). Demographics and health care utilization between those who did or did not develop are described in Table 1. Co-morbidities associated with those who did or did not develop DVT are described in (Table 2). Conclusion: DVT & PE are major avoidable complications of Total Knee replacement and are associated with significant mortality and health care costs. These data demonstrate that there may not be any significant differences in age and associated co-morbidities between those who do or do not develop DVT/PE following total knee replacement except for UTI which can be attributed to the difference in length of stay. The absence of serious co-morbidities like AF and CHF in both groups suggest those with serious co-morbidities may not be receiving total knee replacement. That no differences were noticed in associated co-morbidities among those who did or did not develop DVT/PE following TKR provide the rationale for further study of factors contributing to this serious complication of TKR. Such studies may inform future strategies for prevention of post-operative DVT/PE. Disclosure: No relevant conflicts of interest to declare.

2488 Poster Board II-465 BACKGROUND. Limited data exist about the national burden of emergency department (ED) care for patients with sickle cell disease (SCD). The proportion of patients being seen in the ED who require hospitalization and factors contributing to the above are poorly understood. We present here analysis of such potential factors from the largest nationally representative ED visit data till date. METHODS. The Nationwide Emergency Department Sample (NEDS) is one of a family of databases and software tools developed as part of the Healthcare Cost and Utilization Project (HCUP), a Federal-State-Industry partnership sponsored by the Agency for Healthcare Research and Quality. The NEDS was constructed using records from both the HCUP State Emergency Department Databases and the State Inpatient Databases. The NEDS is the largest all-payer ED database and contains almost 26 million records for ED visits for over 950 hospitals and approximates a 20-percent stratified sample of U.S. hospital-based ED's thus generating weighted estimates of over 120 million ED visits. The following ICD-9-CM diagnosis codes were used to define SCD related hospitalizations: 28241, 28242, 2825, 28260, 28261, 28262, 28263, 28264, 28268, and 28269 and only ‘primary discharge diagnosis' patients were considered. We analyzed the NEDS data for the year 2006. RESULTS. Approximately three-quarters of the total in-patient admissions for SCD in 2006 came through the emergency department. The total number of patients presenting to the ED with SCD as primary diagnosis was 166,043. Of these visits, 68,420 (41.2%) resulted in admission to the hospital. There was a statistically significant difference (p<0.001) in the proportion of ER visits resulting in hospitalization for the following factors (each studied independently): CONCLUSION. SCD is responsible for a significant burden of ED care in the US. A number of factors including of patient age, insurance status, income, hospital type and location may impact the likelihood of subsequent admission to the hospital. High quality care of uncomplicated pain crises in an ED or day hospital is believed to result in a decrease of avoidable hospitalizations. However, the multiplicity of factors independently associated with likelihood of subsequent hospitalization as demonstrated by these data suggest the need for caution in using the proportion of ED visits resulting in hospitalizations as a surrogate marker of quality of care. Disclosures: No relevant conflicts of interest to declare.

1539 Background: Deep vein thrombosis (DVT) and pulmonary embolism (PE) are the major cardiovascular killers in the hospital setting. While there is increasing understanding of the public health importance of DVT there are limited data on the trends in the distribution of DVT in different age groups. Aim: The aim of this study was to study national trends in age distribution of DVT in patients over the age of 45 years in the last decade. Methods: We used the National Inpatient Sample (NIS) to analyze the epidemiology of hospitalizations in various age groups from 1997 – 2007. The NIS is a part of the Healthcare Cost and Utilization Project (HCUP) sponsored by the Agency for Health Care Research and Quality (AHRQ) and contains information from a 20% stratified sample of hospitals extrapolated to show the entire national utilization in United States. For our study we selected the following ICD-9 codes to represent DVT (ICD-9 codes 451.11, 451.19, 451.2, 451.81, 451.9, 453.40, 453.41, 453.42, 453.8, 453.9). For each hospitalization, NIS allows a total of up to 15 diagnostic entries. The entry in the diagnostic (DX) field 1 is called the Principal Diagnosis (PD) is the principal reason for admission and the entries between DX fields 1 and DX field 15 are called all-listed diagnoses and include the principal diagnosis plus additional conditions that coexist at the time of admission, or that develop during the stay. We derived at Secondary diagnoses (SD) by excluding PD of DVT from the list of AD. U.S. Population Census Bureau was used to calculate the change in population. Predictive Analytics Software, IBM PASW Statistics 18.0 data analysis tool were used for data mining and statistical analysis and least square regression analysis was used to calculate ‘p’ value. Result: From 1997 – 2007, Conclusion: These data describe for the first time, trends in the relative contribution of different age groups to the burden of DVT among hospitalized patients in the United States. The population between age group 45–64 years is growing symmetrically as a proportion of the total population, total hospitalized population and total hospitalized population with DVT. On the other hand the population 65–84 years of age is decreasing as a proportion of the total hospitalized population with DVT to an even greater degree than as a proportion of the total population and the total hospitalized population. The group over 85 years remains a disproportionately large contributor to the population with DVT. These data suggest the need for greater study of the distribution of DVT, the underlying causes and potential strategies to prevent DVT in different age groups Disclosures: No relevant conflicts of interest to declare.

4608 Background Acute chest syndrome (ACS) is a major cause of morbidity and the leading cause of mortality in patients with sickle cell disease (SCD). While the causes, outcome, and response to therapy in ACS has been described before, there is scant literature on current nationally representative estimates of burden, characteristics and cost of hospitalizations for SCD patients with ACS. Methods The Nationwide Inpatient Sample (NIS) database, sponsored by the Agency for Health Care Quality and Research, is a stratified probability sample of 20% of all hospital discharges among U.S. community hospitals (n=1,044, sampling universe = 90% of all such discharges). Sampling weights were applied to represent all community hospital discharges in the US for the year 2007. Presence of following ICD-9-CM diagnosis codes were used to define SCD related hospitalizations: 28241, 28242, 2825, 28260, 28261, 28262, 28263, 28264, 28268, and 28269. ICD-9-CM 517.3 was used to identify ACS as a diagnosis during hospitalization for SCD. Only data on SCD related hospitalizations were analyzed. Results In 2007, there were 86,318 discharges nationwide with a primary diagnosis and 79,766 with a secondary diagnosis of SCD (total=166,084). Of these, 7039 (4.2%) had ACS as a complication. Though, males represented 37.5% of SCD related hospitalizations but accounted for 52.1% of ACS episodes. ACS was more common complication in those with age <18 yrs than 18-44 age group (8.1% vs. 3.5%) Pulmonary hypertension as one of the discharge diagnosis was reported in 4.7% of the patients with ACS as compared to 2.2% of the patients without ACS (p <0.001). At least one simple transfusion was seen in 43.0% of SCD patients admitted with a ACS compared to 21.7% without ACS (p-value <0.001). Exchange transfusion (3.6% vs. 0.4%; p <0.001) and mechanical ventilation (2.2% vs. 0.7%; p<0.001) were more frequently among hospitalizations with ACS than without it.. The mean (SD) length of hospitalization in SCD patients with ACS was higher (6.9±0.3 vs. 5.2±0.1; p<0.001) than those without ACS. The mean length of stay by various age categories is depicted in Table 1. Presence of ACS was associated with significantly higher mean charges per hospitalization (USD 35145 vs. USD 22836; p<0.001) Higher in-hospital mortality (1.3% vs. 0.5%, p<0.001) was seen among SCD hospitalizations with ACS as complications than without. The majority of deaths were in the 18-44 years age group (69.9%) followed by 18.2% deaths in <18 years group. Conclusions ACS is a major and common complication in hospitalizations with SCD as a discharge diagnosis. Among SCD patients, presence of ACS is associated with an increased risk of receiving a simple or exchange transfusion, mechanical ventilation, increased length of hospital stay, higher hospital charges and in-hospital mortality. Disclosures: No relevant conflicts of interest to declare.

1540 Background: Increasing burden of Deep venous thrombosis (DVT) among middle aged and older hospitalized patients is well known. However, little is understood about the factors contributing to DVT in this population. DVT in patients admitted to hospital with this as the PD may represent a different set of etiologies and disease processes as compared to DVT occurring secondary to other disease processes which resulted in the initial admission. Aim: To determine the diagnoses and procedures associated with DVT in patients 45 years age and above as PD as compared to those in whom DVT is a SD. Methods: National Inpatient Sample (NIS) database (2007) was utilized to analyze the changing epidemiology in DVT admissions. The NIS is a part of the Healthcare Cost and Utilization Project (HCUP) sponsored by the Agency for Health Care Research and Quality (AHRQ). For each hospitalization, NIS allows a total of up to 15 diagnostic entries. The entry in the diagnostic (DX) field 1 is called the PD and is always the reason for admission. The entries between DX fields 1 and DX field 15 are called all-listed diagnoses and include the PD plus additional conditions that coexist at the time of admission, or that develop during the stay. We derived secondary diagnosis (SD) by excluding primary diagnosis (PD) of DVT from the list of All Diagnoses. SD refer to additional diagnoses that appear with the PD we have chosen. We selected the following ICD-9 codes to represent DVT (ICD-9 codes 451.11, 451.19, 451.2, 451.81, 451.9, 453.40, 453.41, 453.42, 453.8, 453.9). The common diagnoses and procedures associated when DVT is principal vs. SD is calculated above the age group 45 as the associations might be different from critical age point. The output results were obtained in ICD-9 coding and the procedures pertaining to diagnosis of DVT like USG, CAT scans etc. were excluded to determine the association of procedures done for other associated co-morbidities. The top procedures and diagnosis for SD of DVT was taken and were compared with PD of DVT. IBM SPSS Statistics 18 was used for data mining and analysis. Results: From 1997–2007, the overall number of admissions for DVT increased from 364,079 to 532,759 but DVT as PD decreased from 165,442 to 151,295 while the admissions for DVT as SD increased from 198,637 to 381,464.In our study group above 45 years, the median age for admission for DVT both PD and SD is 71 years. Median charges for admission for DVT as PD is 13760$ and for SD is 37588$. While Hypertension and Diabetes Mellitus are the commonest co-morbidities in both the primary SD group. Patients in whom DVT is a SD are more likely to have serious co-morbidities such as Congestive heart failure or Atrial Fibrillation (Table 1)and are more likely to have undergone invasive procedures such as venous catheterization, endotracheal intubation and hemodialysis or received packed red cell transfusion (Table 2). Conclusion: These data demonstrate that DVT as PD is decreasing and DVT as SD is increasing in the US. Further, patients with DVT as SD are more likely to have had serious medical morbidities such as Atrial Fibrillation, urinary tract infection and congestive heart failure or to have undergone invasive procedures such as venous catheterization, endotracheal intubation and mechanical ventilation which may be undergone by individuals with serious medical illnesses. These differences in co-morbidities suggest that the etiologies of DVT as principal and DVT as SD may be significantly different. These data provide the rationale for further study to determine the contributory factors to DVT as PD and SD. Such studies may generate insights that can inform future strategies to address the rising national trend of DVT. Disclosures: No relevant conflicts of interest to declare.