Clinical question: Is the diagnosis of cardiovascular disease (CVD) associated with the risk of subsequent hip fracture?
Background: Osteoporosis and CVD are regarded as independent, age-related conditions. However, recent research suggests that the bone and vascular systems share common regulatory mechanisms. Stroke is a known risk factor for hip fractures, and bisphosphonates have been shown to prevent atherosclerosis and reduce total mortality rate.
Study design: Cohort study.
Setting: Swedish National Patient Registry.
Synopsis: The study identified 31,936 Swedish twins born from 1914 to 1944. This cohort was followed up to age 50, and time-dependent exposures using Cox-proportional hazard regression models were evaluated.
Times to hip fracture after CVD diagnosis were isolated. Crude absolute rate of hip fractures (per 1,000 person-years) was 12.6 after diagnosis of heart failure, 12.6 after a stroke, 6.6 after peripheral atherosclerosis, and 5.2 after ischemic heart disease (IHD), compared with 1.2 per 1,000 person-years without a CVD diagnosis. Multivariable-adjusted hazard ratio (HR) of hip fracture after heart failure was 4.40 (95% CI, 3.43-5.63); after a stroke was 5.09 (95% CI, 4.18-6.20); after peripheral atherosclerosis was 3.20 (CI, 2.28-4.50); and after an IHD event was 2.32 (CI, 1.91-2.84).
Identical twins even without heart failure and stroke also had an increased risk of hip fracture if their twin had been diagnosed with these diseases.
Bottom line: Cardiovascular disease is significantly associated with risk of subsequent hip fracture, and genetic factors probably play a role in the association.
Citation: Sennerby U, Melhus H, Gedeborg R, et al. Cardiovascular diseases and risk of hip fracture. JAMA. 2009;302(15):1666-1673.