High prevalence of osteoporotic vertebral fractures in patients with Crohn's disease

Abstract

Background and aims: Osteopenia and osteoporosis are frequent in Crohn's disease. However, there are few data on related vertebral fractures. Therefore, we evaluated prospectively the prevalence of osteoporotic vertebral fractures in these patients.

Methods: A total of 293 patients were screened with dual energy x ray absorptiometry of the lumbar spine (L1-L4) and proximal right femur. In 156 patients with lumbar osteopenia or osteoporosis (T score <-1), x ray examinations of the thoracic and lumbar spine were performed. Assessment of fractures included visual reading of x rays and quantitative morphometry of the vertebral bodies (T4-L4), analogous to the criteria of the European Vertebral Osteoporosis Study.

Results: In 34 (21.8%; 18 female) of 156 Crohn's disease patients with reduced bone mineral density, 63 osteoporotic vertebral fractures (50 fx. (osteoporotic fracture with visible fracture line running into the vertebral body and/or change of outer shape) and 13 fxd. (osteoporotic fracture with change of outer shape but without visible fracture line)) were found, 50 fx. in 25 (16%, 15 female) patients and 13 fxd. in nine (5.8%, three female) patients. In four patients the fractures were clinically evident and associated with severe back pain. Approximately one third of patients with fractures were younger than 30 years. Lumbar bone mineral density was significantly reduced in patients with fractures compared with those without (T score -2.50 (0.88) v -2.07 (0.66); p<0.025) but not at the hip (-2.0 (1.1) v -1.81 (0.87); p=0.38). In subgroups analyses, no significant differences were observed.

Conclusions: In patients with Crohn's disease and reduced bone mineral density, the prevalence of vertebral fractures-that is, manifest osteoporosis-was strikingly high at 22%, even in those aged less than 30 years, a problem deserving further clinical attention.

Figure 1

Height measurement: quantitative x ray evaluation (quantitative morphometry) using six point digitisation to calculate the anterior (H_a), mid (H_m), and posterior (H_p) height of a vertebral body. (A) Normal shaped vertebra without fracture. (B) Osteoporotic fractured vertebra with concave deformation.

Figure 2

Vertebral column of a female patient with Crohn’s disease with multiple vertebral fractures at the lumbar and thoracic spine. (A) Lumbar spine; (B) thoracic spine.