Prevalence and progression of arterial calcifications on computed tomography in humans with knee osteoarthritis

Objectives: Ectopic bone deposition plays an important role in OA and in arterial wall disease. We aimed to investigate the prevalence and progression of arterial calcifications on whole-body CT in persons with knee OA. Methods: We included 118 (36 male) participants who satisfied the clinical ACR classification criteria for knee OA. Baseline investigations included WOMAC and Kellgren–Lawrence grading. At baseline and after 2 years, a whole-body CT was performed using the same scanner and protocol. Calcifications were quantified in the carotid, brachiocephalic, coronary, thoracic aortic, abdominal aortic, iliac, femoropopliteal and crural arteries. Multivariable linear and logistic regression modelling was used for analyses. Results: At baseline males were 66.9 ± 7.7 and females were 68.0 ± 5.6 years old. Calcifications were common, all participants except two females had some calcification, and prevalence ranged between 41.8% and 94.4% for various arterial beds. Baseline femoropopliteal calcifications were associated with a higher Kellgren–Lawrence grade (more severe knee OA). Median annual progression rate was 13.1% in males and 15.7% in females. Structural OA severity was not associated with progression, but a five points lower (worse) WOMAC was associated with 1% faster progression of arterial calcifications (P = 0.008). Conclusion: Around age 70 years nearly all persons with knee OA have arterial calcifications, which progress substantially. For further investigation into shared causality intervention studies are needed.