REPORTING FROM THSNA 2018

SAN DIEGO (FRONTLINE MEDICAL NEWS) – Pediatric hematologists should consider testing for vitamin D deficiency to optimize bone health in children who will be receiving chronic anticoagulation. That’s a key message from a single-center retrospective review presented during a poster session at the biennial summit of the Thrombosis & Hemostasis Societies of North America.

“More research is needed to determine which children should be targeted for screening for low [bone mineral density], though our research suggests that children with prolonged treatment with steroids may be at the highest risk,” Kavita N. Patel, MD, one of the study’s authors, said in an interview.

While the use of chronic anticoagulation in adults has been shown to be associated with reduced bone mineral density (BMD), there is a paucity of research in children who are taking long-term anticoagulation and its effects on BMD, said Dr. Patel, of the department of pediatrics at Emory University, Atlanta.

“A few studies have shown reduced BMD in children taking warfarin,” she said. “Subsequently, recommendations have been published that children receiving chronic anticoagulation undergo bone density testing. This study sought to determine if children who were receiving chronic anticoagulation [not only warfarin but also low molecular weight heparins and direct oral anticoagulants] had low BMD and whether the length of anticoagulation or any other medical conditions or medications affected the probability of having low BMD. We also wanted to report on the prevalence of low vitamin D in this same group of children since low vitamin D is a known risk for low BMD.”

The study population was a retrospective cohort of children aged 10-21 years who received anticoagulation for more than 1 year at Children’s Healthcare of Atlanta between Jan. 2, 2012, and Oct. 15, 2017. The researchers evaluated a number of factors, including demographic variables, anticoagulants used, vitamin D status, previously reported comorbid conditions and medications associated with changes in BMD. They defined vitamin D deficiency as less than 20 ng/mL and insufficiency as 20-29 ng/mL.

Dr. Patel reported results from 27 males and 23 females. Of these, 15 (30%) underwent bone density testing with dual-energy X-ray absorptiometry; 5 (10%) did not undergo dual-energy X-ray absorptiometry testing because there is no age-specific standardization below the age of 5 years. Nearly half of the patients (42%) were Caucasian, 34% were African American, 16% were Hispanic, and the rest were from other ethnicities. The top four common indications for extended anticoagulation were recurrent venous thromboembolism (26%), extended treatment for deep vein thrombosis (18%), antiphospholipid syndrome (14%), and thrombophilia plus a single venous thromboembolism (14%).

The anticoagulants most often utilized were enoxaparin (59%), warfarin (29%), and rivaroxaban (7%). The most frequent risk factor for low BMD was long-term use of steroids (16%; defined as greater than 6 months of continuous use in the year prior to BMD testing).

Vitamin D deficiency was identified in 52% of subjects who were tested, while another 24% had insufficient levels of vitamin D. Overall, the median lumbar spine z score was –1.4. Five (30%) subjects who completed BMD testing had low BMD, with median z score of –2.5. None met fracture criteria for pediatric osteoporosis. On linear regression, the only factor found to be significantly associated with a BMD lumbar spine z score in chronically anticoagulated children was the long-term use of steroids (P = .04).

Dr. Patel acknowledged certain limitations of the study, including its single-center design and the fact that not all of the children receiving chronic anticoagulation could be tested.

She reported having no financial disclosures.

dbrunk@frontlinemedcom.com

SOURCE: Patel KN et al. THSNA 2018, Poster 65 .

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