Obesity may increase risk for pediatric VTE

Issue: July 25, 2016

Obesity may be a significant risk factor for venous thromboembolism among children, according to results of a single-institution study.

Multiple risk factors for pediatric VTE have been identified, such as bloodstream infection and prolonged hospitalization. Although obesity is a well-established risk factor for VTE in adults, previous studies pertaining to its impact in children have produced mixed results.

Additionally, children with obesity require increased enoxaparin dosing for VTE prophylaxis.

Elizabeth E. Halvorson, MD, instructor in pediatrics at Wake Forest School of Medicine, and colleagues conducted a retrospective case–control study to identify the risk for VTE in this population. The analysis included 88 children (mean age, 11.9 ± 5.2 years; 45% male) with VTE and two matched control subjects per case.

“We hypothesized that obesity would have a positive association with VTE, especially among adolescents whose physiology may more closely resemble that of adults,” researchers wrote.

Of the 88 cases, 77% were nonembolic events. Twenty-five percent occurred in the lower extremity and 22% occurred in the head and neck. Forty-three percent were confirmed by ultrasound and 41% were confirmed by CT scan.

The mean BMI percentile was 74 ± 30 among patients and 64.5 ± 29.3 among controls. Thirty-eight percent of patients with VTE were obese compared with 24% of controls.

Using univariate analysis, risk factors significantly associated with VTE included presence of a central venous catheter (P = .001), bacteremia (P = .012), ICU admission (P = .001), immobilization (P = .001) and use of estrogen-containing oral contraceptives (P < .001).

Researchers also found a statistically significant association between VTE and an increased BMI z score (P = .002).

After adjusting for known risk factors using multivariate regression, use of estrogen-containing oral contraceptives (OR = 17.4; 95% CI, 3.6-83.6), bacteremia (OR = 4.9; 95% CI, 1.3-18.2), BMI z score (OR = 3.1; 95% CI, 1.4-7) and ICU admission (OR = 2.5; 95% CI, 1.2-5.3) significantly increased risk for VTE.

The researchers acknowledge their study may be limited by the omission of VTE and thrombophilia screening to verify disease in control subjects, as well as the relatively small sample size.

“Knowledge of risk factors for pediatric VTE is important given the rising incidence of this condition,” Halvorson and colleagues wrote. “In this single-institution case–control study, we have demonstrated an association between obesity and pediatric VTE, which should be explored further in future studies.” – by Kristie L. Kahl

Reference:

Halvorson EE, et al. Hosp Pediatr. 2016;doi:10.1542/hpeds.2015-0039.

Disclosure: The researchers report no relevant financial disclosures.