Pediatric venous thromboembolism in the United States: a tertiary care complication of chronic diseases

Abstract

Background: Pediatric venous thromboembolism (VTE) is an increasingly common problem. We hypothesized that VTE occurs most commonly in tertiary care settings and that the pattern of associated illnesses may have changed from earlier reports.

Methods: The Kids' Inpatient Database 2006 was utilized to identify children ≤ 18 years old with in-hospital VTE. Children were identified by the presence of thrombosis specific ICD-9-CM diagnosis or procedure codes. Remaining ICD-9-CM codes were utilized to categorize patients by acute or chronic illness. The incidence of in-hospital VTE by hospital type, age, gender, race, and disposition were estimated.

Results: Over 4,500 children met the inclusion criteria (188/100,000 discharges). Most VTE discharges (67.5%) were from children's hospitals (RR 5.09; 95% CI 4.76; 5.44). Underlying chronic illnesses were associated with most VTE (76.2%), most commonly: cardiovascular (18.4%), malignancy (15.7%), and neuromuscular disease (9.9%). VTE not associated with chronic illness were most often idiopathic (12.6%), followed by infections (9.5%), and trauma (9.1%). The greatest proportions of children with VTE were infants (23.1%) and adolescents (37.8%). However, when standardized against the entire database of discharges, infants were least likely to develop VTE (RR 0.48; 95% CI 0.43; 0.52), while adolescents were at highest risk (RR 1.89; 95% CI 1.73; 2.07). Hospitalizations ending with death were more likely to include VTE (RR 6.16; 95% CI 5.32; 7.13).

Conclusions: Pediatric VTE is most commonly seen in tertiary care. Adolescents are at greatest risk to develop in-hospital VTE. Patients whose hospitalization ended with death are at much greater risk to develop VTE.

Figure 1

KID 2006 VTE Case Selection Strategy.

Figure 2

The age distribution of KID 2006 VTE-positive discharges conforms to the well described bi-modal distribution (A). However, when the age distribution is standardized for the number of discharges in each category, the youngest children (both infants and neonates) are least likely to develop VTE, while adolescents aged 15–18 years are most likely (categoricalχ² P <0.00001) (B). The differences in incidence of VTE between children’s and community hospitals are significant (dichotomous χ² P <0.00001) in all age categories (B). The age distribution for children <1 year of age from the 32 KID states that report age in days are shown in the insets.

Figure 3

The distribution of diseases associated with in-hospital VTE (>100% because some discharges were associated with more than one Complex Chronic Condition or had both a CCC and a trauma code) (A). *Other Chronic Illness includes chronic pediatric diseases that are not included in the published CCC, such as histiocytosis, aplastic anemia, or diabetes mellitus. The ratio of acute to chronic conditions associated with in-hospital VTE changes with age (P <0.00001) (B).