Importance: Appropriate risk stratification for venous thromboembolism (VTE) is essential to providing appropriate thromboprophylaxis and avoiding morbidity and mortality.
Objective: To validate the Caprini VTE risk assessment model in a previously unstudied high-risk cohort: critically ill surgical patients.
Design, setting, and participants: We performed a retrospective cohort study of 4844 adults (≥18 years old) admitted to a 20-bed surgical intensive care unit in a large tertiary care academic hospital during a 5-year period (July 1, 2007, through June 30, 2012).
Main outcomes and measures: The main study outcome was VTE (defined as patients with deep vein thrombosis or pulmonary embolism) that occurred during the patient's initial hospital admission.
Results: The study population was distributed among risk levels as follows: low, 5.3%; moderate, 19.9%; high, 31.6%; highest, 25.4%; and superhigh, 14.9%. The overall incidence of inpatient VTE was 7.5% and increased with risk level: 3.5% in low-risk patients, 5.5% in moderate-risk patients, 6.6% in high-risk patients, 8.6% in highest-risk patients, and 11.5% in superhigh-risk patients. Patients with Caprini scores greater than 8 were significantly more likely to develop inpatient VTE events when compared with patients with Caprini scores of 7 to 8 (odds ratio [OR], 1.37; 95% CI, 1.02-1.85; P = .04), 5 to 6 (OR, 1.35; 95% CI, 1.16-1.57; P < .001), 3 to 4 (OR, 1.30; 95% CI, 1.16-1.47; P < .001), or 0 to 2 (OR, 1.37; 95% CI, 1.16-1.64; P < .001). Similarly, patients with Caprini scores of 7 to 8 were significantly more likely to develop inpatient VTE when compared with patients with Caprini scores of 5 to 6 (OR, 1.33; 95% CI, 1.01-1.75; P = .04), 3 to 4 (OR, 1.27; 95% CI, 1.08-1.51; P = .005), or 0 to 2 (OR, 1.38; 95% CI, 1.10-1.74; P = .006).
Conclusions and relevance: The Caprini VTE risk assessment model is valid. This study supports the use of individual risk assessment in critically ill surgical patients.