Prevalence and incidence of vertebral fractures: a 7-year follow-up study in institutionalized adults with refractory epilepsy and intellectual disability.

OBJECTIVE

The main objective of this cohort study is to determine the prevalence and incidence of morphometric vertebral fractures (VFs) over 7 years follow-up, in institutionalized adults with refractory epilepsy and intellectual disability (ID).

METHODS

Dual-energy X-ray Absorptiometry (DXA) and Vertebral Fracture Assessment (VFA) were performed in 2009 and 2016. Vertebrae T4-L4 were assessed using quantitative morphometry. Severity of VFs was graded as 1 (mild; 20-25% reduction in height), 2 (moderate; 25-40% reduction) or 3 (severe; >40% reduction) according to the method described by Genant. Prevalent VFs were analyzed at baseline. VFs (grade 1, 2 or 3) present at follow-up, but not at baseline, were considered new VFs. Worsening VFs were defined as VFs with at least one grade deterioration at follow-up, compared to baseline (grade 1 to 2 or 3, or grade 2 to 3). Patients were treated with anti-osteoporosis treatment according to the Dutch guideline.

RESULTS

Baseline and follow-up DXA and VFA could be obtained in 141 patients (87 male) aged between 18-79 years old (mean 44.8 ± 15.7). At baseline, 56 patients had at least one prevalent VF. Patients with a prevalent VF were significantly older than patients without (49.2 ± 13.7 vs 41.9 ± 16.4, p < .01). After 7 years follow-up, 38 new VFs occurred in 27 patients and 15 patients had a worsening VF, leading to an overall cumulative incidence of 27.0%. VF incidence was significantly higher in patients with at least one prevalent VF at baseline (48.2% vs 12.9%, respectively, p < .01) compared to no VF.

SIGNIFICANCE: In adults with refractory epilepsy VFA is challenging, due to physical and behavioral aspects, resulting in a substantial proportion of unevaluable vertebrae and scans. Nevertheless, 40% of the patients had a VF at baseline and after 7 years follow-up, 27% had at least one new and/or worsening VF despite adequate anti-osteoporosis treatment.