Clinical Decisionmaking

Undiagnosed angina is common and is associated with a two-fold risk of death when ECGs are abnormal

Although most people with symptoms of heart attack seek medical care and obtain a diagnosis from a doctor, people with angina (crushing chest pain that usually occurs during exertion) do not necessarily seek medical care. In fact, an 11-year study of a large group of British civil servants in the 1990s found that over half of them had undiagnosed angina. Furthermore, those with undiagnosed angina and abnormal electrocardiograms (ECGs) at baseline had more than double the risk of death compared with individuals who did not have angina. This risk was similar to those with diagnosed angina and abnormal ECGs. Both groups also had a similar increased risk of non-fatal heart attack and impaired physical functioning.

Researchers, who were supported in part by the Agency for Healthcare Research and Quality (HS06516) and led by Michael Marmot, Ph.D., M.P.H., of the University of Glasgow, examined recurrent angina, quality of life (physical functioning), and non-fatal heart attack among 10,308 British civil servants aged 35-55 years at the beginning of the 11-year study. They also examined death from any cause for 344 participants. Overall, 11.4 percent of the civil servants developed angina, and 74 percent had no evidence of a diagnosis by a doctor at the time of the initial report.

Of these, 65 percent reported angina again during followup and remained without a diagnosis. Among those with an abnormal ECG result, the absolute risk of non-fatal heart attack was similar in those without a diagnosis by a doctor (15 percent) and those with a diagnosis (16 percent). Also, compared with civil servants without angina, those with undiagnosed and diagnosed angina had 2.36 and 3.19 times greater risk, respectively, of impaired physical functioning. These findings underscore the importance of greater vigilance in diagnosing angina so that more patients can be treated.

More details are in "Prognosis of angina with and without a diagnosis: 11 year follow up in the Whitehall II prospective cohort study," by Harry Hemingway, M.D., M.P.H., Martin Shipley, M.Sc., Annie Britton, Ph.D., and others, in the October 18, 2003, British Medical Journal, pp. 1-5.

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