Incidence and predictors of fractures in children after solid organ transplantation: a 5-year prospective, population-based study

Abstract

In this population-based prospective follow-up study, children undergoing solid organ transplantation had a highly elevated risk for fractures: The incidence of all fractures was 6-fold higher (92 versus 14 fractures/1000 persons/year; p < 0.001) and vertebral fractures was 160-fold higher (57 versus 0.35 fractures/1000 persons/year; p < 0.001) in the study group compared with the control population. Thus, screening of vertebral fractures at regular intervals is recommended, and preventive strategies should be studied.

Introduction: The incidence and predictors of fractures after solid organ transplantation are not well documented in the pediatric age group.

Materials and methods: A total of 196 children, which is 93% of patients surviving kidney, liver, and heart transplantation in our country, participated in a retrospective chart review at enrollment followed by a 5-year prospective follow-up study between January 1999 and December 2004. Hospital and medical records were reviewed. All children underwent clinical examinations and answered questionnaires concerning fracture history at the beginning and at the end of the prospective follow-up. Radiographs of the thoracic and lumbar spine were obtained. The fracture incidence was compared with data obtained from public health registries.

Results: Seventy-five (38%) of the transplant patients suffered from a total of 166 fractures after organ transplantation. The incidence of all fractures was 6-fold higher (92 versus 14 fractures/1000 persons/year; p < 0.001) and vertebral fractures was 160-fold higher (57 versus 0.35 fractures/1000 persons/year; p < 0.001) in the study group compared with the control population. The age- and sex-adjusted hazard ratios (95% CI) were 61.3 (40.7-92.4) for vertebral, 17.9 (8.96-35.8) for symptomatic vertebral, 0.99 (0.65-1.50) for nonvertebral, and 2.90 (2.25-3.73) for all fractures in the patients compared with the control population. In a multivariate analysis, older age (hazard ratio [95% CI]; 2.02 [1.07-3.83]), male sex (2.15 [1.22-3.81]), liver transplantation (1.78 [1.01-3.14]), and fractures before transplantation (2.02 [0.92-4.47]) were the most significant independent risk factors.

Conclusions: Children undergoing solid organ transplantation have a highly elevated risk for fractures. Screening of vertebral fractures at regular intervals is recommended, and preventive strategies should be studied.