Poor lung function appears to be a stronger marker of risk for sudden cardiac death than for a survivable first coronary event, results of a prospective population-based study suggest.
Among 28,584 adults with no history of acute coronary events who were followed over 4 decades, every standard deviation decrease in forced expiratory volume in 1 second (FEV1) was associated with a 23% increase in risk for sudden cardiac death, reported Suneela Zaigham, PhD, a cardiovascular epidemiology fellow at the University of Lund, Sweden, and colleagues.
“Our main findings and subsequent conclusions are that low FEV1 is associated with both sudden cardiac death and nonfatal coronary events but is consistently more strongly associated with future sudden cardiac death,” Dr. Zaigham said in a narrated poster presented at the European Respiratory Society (ERS) 2021 International Congress, which was held online.
“We propose that measurement with spirometry in early life could aid in the risk stratification of future sudden cardiac death, and our results support the use of spirometry for cardiovascular risk assessment,” she said.
Marc Humbert, MD, PhD, professor of respiratory medicine at Université Paris–Saclay, who was not involved in the study, said that “this is something we can measure fairly easily, meaning that lung function could be used as part of a screening tool.
“We need to do more research to understand the links between lung function and sudden cardiac death and to investigate whether we can use lung function tests to help prevent deaths in the future,” he said.
Fatal vs. nonfatal events
It is well known that poor lung function is a strong predictor of future coronary events, but it was unknown whether patterns of lung impairment differ in their ability to predict future nonfatal coronary events or sudden cardiac death, Dr. Zaigham said.
To see whether measurable differences in lung function could predict risk for both fatal and nonfatal coronary events, the investigators studied 28,584 middle-aged residents of Malmö, Sweden. Baseline spirometry test results were available for all study participants.
The patients were followed for approximately 40 years for sudden cardiac death, defined as death on the day of a coronary event, or nonfatal events, defined as survival for at least 24 hours after an event.
Dr. Zaigham and colleagues used a modified version of Lunn McNeil’s competing risks method to create Cox regression models.
Results of an analysis that was adjusted for potential confounding factors indicated that one standard deviation reduction in FEV1 was associated with a hazard ratio (HR) for sudden cardiac death of 1.23 (95% confidence interval, 1.15-1.31). In contrast, one standard deviation in FEV1 was associated with a lower but still significant risk for nonfatal events, with an HR of 1.08 (95% CI, 1.04-1.13; P for equal associations = .002).
The results remained significant among participants who had never smoked, with an HR for sudden cardiac death of 1.34 (95% CI, 1.15-1.55) and for nonfatal events of 1.11 (95% CI, 1.02-1.21; P for equal associations = .038).
“This study suggests a link between lung health and sudden cardiac death. It shows a higher risk of fatal than nonfatal coronary events even in people whose lung function is moderately lower but may still be within a normal range,” Dr. Humbert said.
The study was supported by the Swedish Heart-Lung Foundation. Dr. Zaigham and Dr. Humbert reported having no relevant financial relationships.
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