Vertebral fractures at hospitalization predict impaired respiratory function during follow-up of COVID-19 survivors

Purpose Morphometric vertebral fractures (VFs) have been recently reported as an important component of the endocrine phenotype of COVID-19 and emerging data show negative respiratory sequelae at long-term follow-up in COVID-19 survivors. The aim of this study was to evaluate the impact of VFs on respiratory function in COVID-19 survivors. Methods We included patients referred to our Hospital Emergency Department and re-evaluated during follow-up. VFs were detected on lateral chest X-rays on admission using a qualitative and semiquantitative assessment and pulmonary function tests were obtained by Jaeger-MasterScreen-Analyzer Unit 6 months after discharge. Results Fifty patients were included. Median age was 66 years and 66% were males. No respiratory function data were available at COVID-19 diagnosis. VFs were detected in 16 (32%) patients. No differences between fractured and non-fractured patients regarding age and sex were observed. Although no difference was observed between VF and non-VF patient groups in the severity of pneumonia as assessed by Radiological-Assessment-of-Lung-Edema score at admission, (5 vs. 6, p = 0.69), patients with VFs were characterized as compared to those without VFs by lower Forced Vital Capacity (FVC, 2.9 vs. 3.6 L, p = 0.006; 85% vs. 110% of predicted, respectively, p = 0.001), Forced Expiratory Volume 1st s (FEV1, 2.2 vs. 2.8 L, p = 0.005; 92% vs. 110% of predicted, respectively, p = 0.001) and Diffusing Capacity of the Lungs for Carbon Monoxide (DLCO 5.83 vs. 6.98 mmol/min/kPa, p = 0.036, 59% vs. 86.3% of predicted, respectively, p = 0.043) at 6-month follow up. Conclusions VFs, expression of the endocrine phenotype of the disease, appear to influence medium-term impaired respiratory function of COVID-19 survivors which may significantly influence their recovery. Therefore, our findings suggest that a VFs assessment at baseline may help in identifying patients needing a more intensive respiratory follow-up and patients showing persistent respiratory impairment without evidence of pulmonary disease may benefit from VFs assessment to preventing the vicious circle of further fractures and respiratory deterioration.