Lead author Ziyad Al-Aly, a clinical epidemiologist at Washington University, said he and his colleagues were surprised to see the spectrum of people affected by covid-19 cardiovascular problems. The researchers statistically compensated for the scarcity of women and people of colour. The veteran population tends to be older, white, and male. As controls, they created a cohort of 5 637 647 people as contemporary controls and a cohort of 5 859 411 people as historical controls to estimate risks and one year burdens of a set of pre-specified incident cardiovascular outcomes. The researchers used national healthcare databases from the US Department of Veterans Affairs to build a cohort of 153 760 people who had survived the first 30 days of covid-19 infection between March 2020 and January 2021. The researchers wrote that the increased risks “were evident regardless of age, race, sex, and other cardiovascular risk factors, including obesity, hypertension, diabetes, chronic kidney disease, and hyperlipidemia they were also evident in people without any cardiovascular disease before exposure to covid-19, providing evidence that these risks might manifest even in people at low risk of cardiovascular disease.” However, the way covid-19 infection might cause cardiovascular problems remains unclear, they said. Those who had had covid-19 had a 72% increased risk of heart failure, 63% increased risk of heart attack, and 52% increased risk of stroke compared with controls. Even those who had not been admitted to hospital with covid-19 were at risk of these problems, but the risk increased with the severity of the infection, from people not admitted to hospital to those admitted to intensive care. The authors from Washington University and the Veterans Administration Health Care System in St Louis, Missouri, reported in Nature Medicine that one year after covid-19 infection people were at higher risk of cardiovascular disease, including cerebrovascular disorders, dysrhythmias, ischaemic and non-ischaemic heart disease, pericarditis, myocarditis, heart failure, and thromboembolic disease. Infection with SARS-CoV-2 can cause cardiovascular problems for up to a year, not just during the acute phase, a large study has found.