Determinants of venous thromboembolism among hospitalizations of US adults: a multilevel analysis

Abstract

Background: Venous thromboembolism (VTE) is a significant clinical and public health concern. We evaluated a variety of multilevel factors--demographics, clinical and insurance status, preexisting comorbid conditions, and hospital characteristics--for VTE diagnosis among hospitalizations of US adults.

Methods: We generated adjusted odds ratios with 95% confidence intervals (CIs) and determined sources of outcome variation by conducting multilevel logistic regression analysis of data from the 2011 Nationwide Inpatient Sample that included 6,710,066 hospitalizations of US adults nested within 1,039 hospitals.

Results: Among hospitalizations of adults, age, sex, race or ethnicity, total days of hospital stay, status of health insurance, and operating room procedure were important determinants of VTE diagnosis; each of the following preexisting comorbid conditions--acquired immune deficiency syndrome, anemia, arthritis, congestive heart failure, coagulopathy, hypertension, lymphoma, metastatic cancer, other neurological disorders, obesity, paralysis, pulmonary circulation disorders, renal failure, solid tumor without metastasis, and weight loss--was associated independently with 1.04 (95% CI: 1.02-1.06) to 2.91 (95% CI: 2.81-3.00) times increased likelihood of VTE diagnosis than among hospitalizations of adults without any of these corresponding conditions. The presence of 2 or more of such conditions was associated a 180%-450% increased likelihood of a VTE diagnosis. Hospitalizations of adults who were treated in urban hospitals were associated with a 14%-15% increased likelihood of having a VTE diagnosis than those treated in rural hospitals. Approximately 7.4% of the total variation in VTE diagnosis occurred between hospitals.

Conclusion: The presence of certain comorbidities and hospital contextual factors is associated with significantly elevated likelihood of VTE diagnosis among hospitalizations of adults. The findings of this study underscore the importance of clinical risk assessment and adherence to evidence-based clinical practice guidelines in preventing VTE, as well as the need to evaluate potential contextual factors that might modify the risk of VTE among hospitalized patients.

Fig 1. Number and percentage distributions of hospitals (n = 1,039) by hospital characteristics, NIS, 2011.

Fig 2. Percentage distribution of hospitalizations of US adults and odds ratios for VTE diagnosis by number of selected preexisting comorbid conditions, NIS, 2011.