Clinical vertebral fractures are the most common osteoporotic fracture and are associated with increased mortality risk. However, 2/3 of these are asymptomatic (AVFs) and do not come to medical attention. The role of AVF on mortality risk is unknown.
Aims: This study aimed to determine the association between AVFs and mortality risk in older participants.
Methods: Participants, aged 50+ from the Canadian Multicentre Osteoporosis Study, were followed for 17 years. AVFs were determined at baseline from spine X-rays by trained radiologists using the Genant Method of grades 1, 2 and 3 according to respective 20-25%, 25-40% and >40% loss of vertebral height. Mortality risk for maximum grade and number of AVFs were evaluated using gender-specific Cox-proportional hazards models, adjusted for age and multi-morbidities.
Results: The cohort included 1755 men and 4442 women, of which 254 (14.5%) and 611 (13.8%), respectively, had an AVF. There was 8.6%, 4.3% and 1.5% of men with a maximum grade of 1,2 and 3 respectively and 6.6%, 4.8% and 2.4% for respective groups in women. There were 450 deaths in men and 795 in women over 71703 person-years. Kaplan-Meier curves demonstrated increased mortality risk only for grades ≥2. Therefore, grade 1 AVFs were included with no fracture in the Cox-model.
Maximum grade 2 was associated with increased mortality risk by 1.14 (0.76-1.72) and 1.08 (0.81-1.42) and maximum grade 3 with 1.46 (0.85-2.54) and 1.61 (1.17-2.23) for men and women respectively.
Mortality risk was further increased by increasing number of AVFs; by 1.31 (0.69-2.48) and 1.45 (1.05-1.50) for 2+ AVFs in men and women respectively.
Conclusion: Moderate to severe AVFs were associated with poorer outcomes in patients and thus should be considered for treatment in the clinical setting. Further research is required to determine whether the excess mortality is mediated by subsequent increased fracture risk.