London, Jan 19 : Covid-19 patients have an elevated risk of death for at least 18 months after they got infected, researchers warned on Thursday. Covid patients were more likely to develop numerous cardiovascular conditions compared to uninfected participants, which may have contributed to their higher risks of death, according to the study of nearly 160,000 participants published in Cardiovascular Research, a journal of the European Society of Cardiology (ESC). "The findings indicate that patients with Covid-19 should be monitored for at least a year after recovering from the acute illness to diagnose cardiovascular complications of the infection, which form part of long Covid," said Professor Ian CK Wong of the University of Hong Kong, China. Compared to uninfected individuals, the likelihood of Covid-19 patients dying was up to 81 times higher in the first three weeks of infection and remained five times higher up to 18 months later. Compared with the two uninfected cohorts, patients with Covid-19 were approximately four times more likely to develop major cardiovascular disease in the acute phase and 40 per cent more likely in the post-acute phase. Compared to uninfected individuals, the risk of death in Covid-19 patients was up to 81-fold higher in the acute phase and five-fold higher in the post-acute phase. Patients with severe Covid-19 were more likely to develop major cardiovascular disease or die than non-severe cases, according to the study. Covid-19 patients had a greater likelihood of several cardiovascular conditions compared with uninfected participants in both the short- and long-term including myocardial infarction, coronary heart disease, heart failure, and deep vein thrombosis. Risks of some cardiovascular conditions -- for example stroke and atrial fibrillation -- were elevated in Covid-19 patients in the short-term but then returned to normal levels. "This study was conducted during the first wave of the pandemic, and future research should evaluate subsequent outbreaks," said professor Wong. /IANS