How stroke, diabetes, heart attack combination reduce life expectancy

HAVING a history of diabetes, stroke or heart attack can lower life expectancy significantly, according to new research, while a combination of two or more of these conditions – defined as cardiometabolic multimorbidity – can reduce it even further.

Researchers estimate that 40-year-olds with a history of diabetes, stroke and heart attack may experience a 23-year reduction in life expectancy. The study was published in the Journal of the American Medical Association (JAMA).

According to study co-author John Danesh, of the University of Cambridge in the United Kingdom (UK), and colleagues, the prevalence of cardiometabolic multimorbidity is on the rise. It affects around 10 million adults within the US and the European Union (EU), they say. Previous studies have established that a history of stroke, heart attack or diabetes alone can increase mortality risk.

But Danesh and colleagues say few studies have looked at how a history of two or more of these conditions may impact life expectancy. They note that to reach valid estimations of this, such studies need to compare individuals with cardiometabolic multimorbidity with those in the same cohorts who are free of such conditions at study baseline.

“However, few population cohorts have had sufficient power, detail and longevity to enable such comparisons,” they add. “We aimed to provide reliable estimates of the associations of cardiometabolic multimorbidity with mortality and reductions in life expectancy.”

The team analyzed data from the Emerging Rick Factors Collaboration, involving 689,300 participants from cohorts conducted between 1960 and 2007. This data were compared with that from the UK Biobank, involving 499,808 participants from cohorts conducted between 2006 and 2010. Data from the Emerging Rick Factors Collaboration included 128,843 deaths, while data from the UK Biobank included 7,995 deaths.

The researchers used the data to estimate mortality rates among individuals with a history of either diabetes, heart attack or stroke, a history of two or more of these conditions or no history of any of these conditions. Adults with cardiometabolic multimorbidity may face 23-year reduction in life expectancy Compared with participants who had no history of diabetes, heart attack or stroke, those who had a history of one of these conditions was found to have twice the rate of death.

However, the death rate was found to be even higher with each additional condition. The rate of death among participants with a history of two of these conditions was four times higher, while the rate of death increased eight-fold for participants who had all three conditions.

Based on these findings, recently published in JAMA, the team estimates that a history of cardiometabolic multimorbidity is associated with a reduced life expectancy similar to that caused by lifelong smoking or HIV – a reduction of around 10 and 11 years, respectively.

At the age of 60, for example, the researchers estimate that an individual with a history of two of the conditions may experience a 12-year reduction in life expectancy, while a 15-year reduction is estimated for those with a history of all three conditions.

For younger individuals with a history of cardiometabolic multimorbidity, the reduction in life expectancy may be even higher. The researchers estimate that individuals aged 40 with a history of diabetes, stroke and heart attack could experience around 23 years of lost life.

On adjusting the results by sex, the team found that the association between a history of stroke or heart attack at study baseline and reduced life expectancy was stronger for men than for women, while the association between diabetes at study baseline and reduced life expectancy was stronger for women.

The researchers estimate that overall, men are likely to experience more lost life years than women as a result of cardiometabolic multimorbidity. “Nevertheless,” they note, “for both men and women, our findings indicate that associations of cardiometabolic multimorbidity extend beyond cardiovascular mortality. Future work will seek to elucidate explanations for these interactions by sex.”

Commenting on their overall findings, the researchers say: “Our results highlight the need to balance the primary prevention and secondary prevention of cardiovascular disease.” “

About one per cent of the participants in the cohorts we studied had cardiometabolic multimorbidity compared with an estimate of three per cent from recent surveys in the United States.

Nevertheless, an overemphasis on the substantial reductions in life expectancy estimated for the subpopulation with multimorbidity could divert attention and resources away from population-wide strategies that aim to improve health for the large majority of the population.”