Experts are calling for targeted measures to prevent cardiovascular disease, especially in younger patients.
A large observational study of almost half a million people with autoimmune disorders has found an increased risk in cardiovascular disease akin to that caused by type 2 diabetes.
The findings, published in The Lancet, have led to calls for increased recognition of the association and targeted measures to prevent cardiovascular disease, especially in younger patients.
Researchers used anonymised patient data from a UK primary care database covering approximately 20% of the UK population to compare the incidence of cardiovascular disease in 446,000 patients with autoimmune diseases to 2.1 million matched controls.
Patients in the autoimmune disease cohort had not been diagnosed with autoimmune disease or cardiovascular disease when first registered with the general practice and for up to 12 months afterwards. Matched control patients were also free of cardiovascular disease diagnosis when first registered with the general practice and for the subsequent 12 months.
Over a median 6.2 year follow up, 15.3% of autoimmune disease patients developed incident cardiovascular disease, compared to 11% without autoimmune disease (23.3 versus 15 events per 1000 patient-years respectively: HR 1.56 [95% CI 1.52-1.59]).
There was no difference in cardiovascular disease risk between men and women in the autoimmune disease cohort, and among all patients that developed cardiovascular disease, the age of onset was significantly younger in the autoimmune disease group than controls (mean age 67.7 vs 70.4 years respectively). Almost one in 10 patients had more than one autoimmune disease, and risk of cardiovascular disease increased with the number of autoimmune diseases a patient had.
Previous studies looking at cardiovascular risk in patients with autoimmune disorders were limited by small numbers of patients, cardiovascular conditions considered and tended to focus on more common autoimmune diseases. The current study included 19 autoimmune disorders, including rarer ones previously overlooked, and 12 cardiovascular outcomes.
Depending on the autoimmune disorder, the increased risk of cardiovascular events ranged from 1.4 to 3.6 times higher than for people without an autoimmune disorder. At the lower end of the range, this is comparable to the known risks associated with type 2 diabetes, hyperlipidaemia or hypertension.
Autoimmune disorders associated with the highest cardiovascular risks were SLE, systemic sclerosis, type 1 diabetes and Addison’s disease, with hazard ratios two to four times higher than the controls.
“Excess risk was particularly high in the young (<45 years) and was not explained by traditional cardiovascular risk factors, such as age, sex, socioeconomic status, blood pressure, BMI, smoking, cholesterol, or type 2 diabetes,” wrote the authors, led by epidemiologist Dr Nathalie Conrad of KU Leuven in Belgium.
The authors noted that the increase in cardiovascular morbidity and mortality associated with certain autoimmune diseases was thought to be due to chronic and systemic inflammation and mediated by the presence of proinflammatory cytokines and autoantibodies.
They found in the current study that while all autoimmune diseases were linked with a higher risk of cardiovascular disease, those with conditions directly associated with inflammation, autoantibody-mediated pathology and endothelial dysfunction, such as lupus and systemic sclerosis, had much higher risk than those with very localised effects, such as psoriasis and vitiligo.
Having observed that infection-related heart diseases were increased in the autoimmune disease cohort, they raised the further possibility that the treatment medications used might make patients more susceptible to these infections and their consequences on the cardiovascular system. One the limitations of the study was the inability to account for the effect of different drugs because of potential confounding due to non-randomised treatment.
“Cardiovascular risk prevention should be considered as an integral part of the management of autoimmune diseases”, wrote the authors.
“Further research is needed to design and assess the effectiveness of cardiovascular prevention measures for patients with autoimmune disorders, such as screening programmes and early use of preventive treatments.”
