Elevated Cardiovascular Risk May Linger for Several Years After a Severe Infection

Hospitalization for sepsis or pneumonia appears to be the prelude to a period of heightened cardiovascular risk, even after the infection resolves, as demonstrated by a study of Swedish men followed for several decades.

Although the raised risk is seen more than 5 years after the infection, it is most pronounced in the first 3 years, with the strength of the relationship waning over time, lead author Cecilia Bergh, PhD (Örebro University, Sweden), and colleagues report in a study published online August 2, 2017, ahead of print in the European Journal of Preventive Cardiology.

Mechanisms are speculative, but senior author Scott Montgomery, PhD (Örebro University and University College London, England), told TCTMD that a boost in systemic inflammation is probably one of the factors driving the elevated cardiovascular risk.

Whatever the reasons, clinicians should recognize that there is a “window of susceptibility” after a severe infection, he said.

“In terms of monitoring, it may be more important to look for signs of cardiovascular disease in the years immediately following a severe infection,” Montgomery said. “If you’re going to consider interventions, this might be a good time to start. It’s always a good idea to give up risks like smoking or to lose excessive weight, but again, given this is a period of particular risk, it might not be a bad idea to think about taking those actions at this time when you’re at greater risk of a cardiovascular event.”

It is well known that severe infections are associated with a greater risk of cardiovascular events in the short term, with some evidence suggesting that vaccination against influenza and pneumonia may protect against CVD, but there are limited data on whether risks persist over a longer period of time.

To explore the issue, the investigators looked at Swedish national registries to track 236,739 men born between 1952 and 1956 from the time of their military conscription assessments—performed at an average age of 18—to 2010.

During follow-up, 19.7% of men received a first diagnosis of any cardiovascular disease, including 4.3% with coronary heart disease and 1.5% with stroke. Overall, 3.6% of men had a first hospitalization for sepsis or pneumonia.

After adjustment for potential confounders, the risk of any cardiovascular disease associated with severe infection was highest in the first year (HR 6.33; 95% CI 5.65-7.09), but it remained more than doubled in the second year (HR 2.47; 95% CI 2.04-3.00) and third year (HR 2.12; 95% CI 1.71-2.62). Risk remained elevated at 5 or more years of follow-up (HR 1.56; 95% CI 1.46-1.67).

Generally similar relationships were seen for coronary heart disease, stroke, and fatal CVD.

“The temporal pattern of association between infections and CVD (initially high and then reducing in magnitude) is suggestive of a causal association,” the authors say, noting that they also performed a sensitivity analysis to account for infections occurring after the first one. “We are not aware of other studies that have examined the role of multiple infectious episodes, but our results indicate that even a single serious infection is associated with a persistent risk of CVD, particularly in the years immediately following the infection.”

Cardiovascular risk was also associated with numerous factors from childhood and adolescence, including having parents with manual occupations, household crowding, high erythrocyte sedimentation rate, higher blood pressure, overweight and obesity, low stress resilience, poorer cognitive function, poor physical fitness, and diagnoses influencing daily life. But none of those variables were as strongly related to CVD as infection out to 3 years.