Dozens of autoimmune diseases linked to pulmonary embolism

Lancet2011; doi:10.1016/S0140-6736(11)61306-8

Researchers have confirmed a powerful association between autoimmune diseases and venous thromboembolism, in a study covering the adult population of Sweden. Adults admitted to hospital with any one of 33 different autoimmune diseases at any time between 1964 and 2008 had a significantly higher risk of pulmonary embolism than the general population in fully adjusted analyses. Risks were highest in the first year after admission and seemed to fall over time, possibly because treatment helped control the inflammatory processes thought to create a procoagulant state, say the authors.

Standardised incidence ratios for pulmonary embolism were highest in the year after admission for immune thrombocytopenic purpura (10.79, 95% CI 7.98 to 14.28), polyarteritis nodosa (13.26, 9.33 to 18.29), polymyositis or dermatomyositis (16.44, 11.57 to 22.69), systemic lupus erythematosus (10.23, 8.31 to 12.45), and ulcerative colitis (10.26, 9.03 to 11.62). Other common autoimmune diseases, including rheumatoid arthritis and type 1 diabetes, were not far behind.

Sweden’s many national databases are famously comprehensive and can be linked using a personal number unique to every citizen. They are a great resource for epidemiologists looking to add power and confidence to previous smaller analyses. These authors studied more than half a million patients with autoimmune diseases, and 15 607 with pulmonary embolism. They weren’t able to explore the role of drugs, immobilisation in hospital, or common cardiovascular risk factors such as smoking. But a causal link between autoimmune disease and venous thromboembolism remains likely, they write. Researchers could now investigate the possibility of prophylaxis for people with the riskiest diseases.

Further reassurance about the long term safety of statins

Lancet2011; doi:10.1016/S0140-6736(11)61125-2

Further reassurance about the long term safety of statins has emerged from extended follow-up of more than 20 000 patients who took part in a placebo controlled trial of simvastatin⇑. The drug reduced concentrations of …