Scoliosis and Cardiopulmonary Outcomes in Osteogenesis Imperfecta Patients

Abstract

STUDY DESIGN: Retrospective clinical study of individuals with osteogenesis imperfecta (OI). OBJECTIVE: To assess the relationship between severity of scoliosis and pulmonary function, and to assess the relationship between restrictive lung disease and self-reported quality of life in individuals with OI. SUMMARY OF BACKGROUND DATA: OI is a heritable connective tissue disorder characterized by osteopenia and a predisposition to fracture. Respiratory insufficiency is a leading cause of mortality. Literature on pulmonary function in this population has shown a negative correlation between percent-predicted vital capacity and severity of scoliosis. However, it has been suggested that decreased pulmonary function in OI may be due to intrinsic pulmonary disease, in addition to the impact of vertebral compression fractures and scoliosis. METHODS: Anterior-posterior spine radiographs and pulmonary function tests from 30 individuals with OI were reviewed. Radiographs were evaluated for scoliosis, defined as a curve ≥ 10°. If more than one curve was present, the largest curve was used. Pulmonary function was defined as the forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) ratio. Restrictive pulmonary disease was defined as FEV1/FVC > 80%, while obstructive disease was defined as FEV1/FVC < 70%. Bivariate correlation analysis was performed, using Spearman rho correlation coefficient (P < 0.05). Quality of life was assessed by SF-36. RESULTS: The mean age was 27.6 years (range: 12-42 yrs). 57.6% were female. OI type IV was the most common (46.7%), followed by OI type III (33.3%), OI type I (10%), OI type IX (6.67% each), and OI type VIII (3.33%). Pulmonary comorbidity was present in 40% of individuals, while 6.67% had a cardiac comorbidity. The correlation between scoliosis and pulmonary function was weak and not significant (R = -0.059, P = 0.747). CONCLUSION: Pulmonary function is not significantly correlated with scoliosis, supporting the hypothesis that decreased pulmonary function is intrinsic to OI and/or chest wall deformities, rather than secondary to scoliosis. LEVEL OF EVIDENCE: 4.