Clinical Features and Outcomes of Respiratory Complications in Patients with Thoracic Hyperkyphosis

Introduction: There are few data about thoracic hyperkyphosis which focused on respiratory events and prognoses. We investigated the clinical features and outcomes of respiratory complications requiring hospitalization in patients with thoracic hyperkyphosis. Methods: Following a retrospective review of the medical records between 2002 and 2011, we included 51 patients with thoracic hyperkyphosis who had visited the respiratory department due to respiratory symptoms. Results: Of total 51 patients, 35 patients were hospitalized due to respiratory events. Among 56 total hospitalized events, acute respiratory failure (ARF) (n = 18) and exacerbation of a chronic airway disorder (n = 18) were the most common causes. Respiratory events related mortality was 13.7 % (7/51). The median value of the thoracic kyphosis angle was 89.0°. The ratio of the measured kyphosis angle to the normal value according to age and sex showed the median value of 2.38 (interquartile range 1.61–2.87). This ratio was negatively correlated with both predicted forced vital capacity (γ = −0.647, p < 0.0001) and predicted forced expiratory volume for 1 s (γ = −0.518, p = 0.008). After adjustments for age and sex, hyperkyphosis (angle ≥90°) was not found to influence the development of ARF (hazard ratio 3.2; 95 % confidence interval, 0.86–12.14; p = 0.082). Conclusions: Patients with thoracic hyperkyphosis presenting to a respiratory department with respiratory issues commonly experienced respiratory events requiring hospitalization and had a poor prognosis. In addition, the severity of the kyphosis angle was correlated with respiratory insufficiency although it was not a risk factor for the development of ARF.