Background: Patients hospitalized for infectious diseases are at risk for venous thromboembolism (VTE) and over 50% of VTE events occur 30-40 days after discharge. In our previous analyses, over 60% of patients hospitalized for an infectious disease in the US did not receive any VTE prophylaxis, and only 5% received both inpatient and outpatient VTE prophylaxis. Without adequate VTE prophylaxis covering the entire risk period, including after discharge, patients may be at risk of VTE-related rehospitalization. The goal of this study was to analyze the frequency and associated cost of VTE-related readmissions among patients with infectious diseases in the US.
Methods: Patients hospitalized for infectious diseases, based on the primary hospital discharge diagnosis codes, were identified from the MarketScan databases (7/1/2011 to 3/31/2015). Eligible patients were ≥40 years and had continuous insurance enrollment ≤6 months prior to initial (index) hospitalizations (baseline period) and >6 months after discharge (follow-up period). The study endpoints were: the proportion of patients readmitted for the primary VTE or any position VTE (VTE-related) during the follow-up period, and the associated resources and costs of readmissions.
Results: Data from 4,500 patients hospitalized for infectious disease were available. Mean age was 65.9 years, 51.9% were female, mean Charlson Comorbidity Index score was 2.3. For index hospitalization, 42.6% of patients were hospitalized for 1-3 days, 38.0% for 4-7 days, 14.4% for 8-14 days, and 5.0% for over 2 weeks. During index hospitalization, 2.7% of patients had a VTE, which was the highest incidence among acute medical illnesses evaluated (cancer, heart failure, ischemic stroke, respiratory disease, rheumatic diseases, and infectious disease). In the 6 months following discharge, 2.0% patients had a VTE-related hospital readmission, of which 23.9% were for a primary diagnosis of VTE. One-quarter (26.1%) of the VTE-related readmissions occurred ≤30 days of hospital discharge. For VTE-related readmissions, mean length of hospital stay (LOS) was 9.6 days and the mean total cost for a hospital readmission was $41,909. For primary VTE readmissions, the mean LOS was 3.9 days and the mean total cost of a readmission was $14,916; for readmissions with a primary diagnosis of DVT or PE, mean total costs were $12,947 or $17,422, respectively.
Conclusions: In this retrospective real-world study, more patients hospitalized for infectious disease than patients hospitalized for any other acute medical illnesses had a VTE, and 2% had a VTE-related hospital readmission. The economic burden of VTE-related or primary VTE hospital readmissions was substantial, with total costs of $41,909 and $14,916, respectively, driven by length of hospital stay due to readmission (9.6 and 3.9 days, respectively). Improvement in VTE prophylaxis may reduce the clinical and economic burden of VTE and associated rehospitalizations in these patients.