The results require further prospective evaluation, Dr. Thompson said.
Another study found a significant risk of developing osteopenia among patients on a KGD, compared with matched controls.
Of 132 children included in the retrospective matched cohort study, 66 were treated with AEDs and a KGD (initiated at a mean age of 4.3 years), and 66 were treated with AEDs alone.
The KGD group had fractures – often unrelated to trauma – more often than did those on AEDs alone (14% vs. 8%, respectively). The incidence of both osteopenia and fractures increased in tandem with the duration of the KGD, according to the group of investigators from the University of British Columbia, Vancouver, led by Dr. Mary B. Connolly.
There was a history of trauma in one-third of the KGD patients with fracture, compared with 100% of those in the AED-only group. In addition, all patients in the KGD group had osteopenia, compared with 60% of those in the control group.
Nonambulatory status was a risk factor for osteopenia and fractures in both groups, and a longer duration of KGD was associated with greater risk. For instance, among those treated for 1-3 years, 4% had fractures and 27% had osteopenia, and among those treated for 4 or more years, 20% had fractures and 43% had osteopenia.
"Our results suggest that prolonged treatment with the KD may be associated with significant morbidity, including osteopenia and fractures," Dr. Connolly wrote, noting that the incidence of osteopenia in the study was likely underestimated because of the retrospective design.
The findings, which support those of prior long-term studies, suggest that monitoring of bone health and vitamin D and calcium supplementation is important in this population, she said.