Objectives: Further survival benefits may be gained from low-dose chest computed tomography (CT) by assessing vertebral fractures and bone density. We sought to assess the association between CT-measured vertebral fractures and bone density with all-cause mortality in lung cancer screening participants.
Methods: Following a case-cohort design, lung cancer screening trial participants (N = 3,673) who died (N = 196) during a median follow-up of 6 years (inter-quartile range: 5.7-6.3) were identified and added to a random sample of N = 383 from the trial. We assessed vertebral fractures using Genant's semiquantative method on sagittal reconstructions and measured bone density (Hounsfield Units (HU)) in vertebrae. Cox proportional hazards modelling was used to determine if vertebral fractures or bone density were independently predictive of mortality.
Results: The prevalence of vertebral fractures was 35% (95% confidence interval 30-40%) among survivors and 51% (44-58%) amongst cases. After adjusting for age, gender, smoking status, pack years smoked, coronary and aortic calcium volume and pulmonary emphysema, the adjusted hazard ratio (HR) for vertebral fracture was 2.04 (1.43-2.92). For each 10 HU decline in trabecular bone density, the adjusted HR was 1.08 (1.02-1.15).
Conclusions: Vertebral fractures and bone density are independently associated with all-cause mortality.
Key points: • Lung cancer screening chest computed tomography contains additional, potentially useful information. • Vertebral fractures and bone density are independently predictive of mortality. • This finding has implications for screening and management decisions.