ESPE Abstracts

Background: Bisphosphonates have been used for treatment of bone fragility disorders for over 25 years to increase bone mineral density (BMD). Anecdotally, bisphosphonate-treated Osteogenesis Imperfecta (OI) has a different trajectory to the natural history of untreated OI, with minimal published evidence to support this clinical observation.

Aims: To describe functional outcomes of a cohort of adults with OI, stratified according to severity and treated with bisphosphonates as children, including fracture incidence before and after puberty, mobility and BMD outcomes of this cohort, compared to adults with OI who were never treated as children.

Methods: All participants completed four questionnaires: a study specific questionnaire addressing fracture and treatment history, WHOQOL-BREF (quality of life), SF-36 (musculoskeletal function) and IPAQ (physical activity), and medical records were reviewed.

Results: Fifty-two adults with OI (80% response rate) completed the questionnaires; 33 of whom were treated with bisphosphonates in childhood. The childhood treated cohort had higher lumbar spine BMD than the adult treated cohort (z-score −0.5 at mean age 21.3 years versus −2.1 at mean age 40.9 years; P=0.005). There were less post-pubertal fractures in severe forms of OI in the childhood treated cohort compared to the adult treated cohort. In less severe OI, childhood treated individuals had higher levels of physical activity and physical functioning than adult treated individuals. Incidence of scoliosis was not different between cohorts. There were no differences in quality of life scores between the two cohorts.

Conclusions: Improvements in BMD correlate with reduction of post-pubertal fracture rates in severe OI but do not appear to influence the prevalence of scoliosis. Results suggest that treatment with bisphosphonates at an earlier age improves physical activity, particularly in less severe forms of OI but may not alter quality of life.