Wanting clarification on a possible higher risk of adult-onset heart failure from a preterm live birth, or gestation of less than 37 weeks, investigators from Sweden conducted a national cohort study of all live singleton births in the country between 1973 and 2014.
Their data show a 42% greater risk of new adult-onset heart failure between the ages of 18 and 43 years if the individual was born before 37 weeks gestation, according to the study published in JAMA Pediatrics.1 There also was an overall 0.1% incidence of heart failure, with a median age of 15.4 years at diagnosis.
“Preterm birth has been associated with increased risk of heart failure early in life, but its association with new-onset heart failure in adulthood appears to be unknown,” the authors noted when explaining why they looked into this outcome.
With a primary outcome of heart failure, the authors also stratified their data by several measures of gestational age: extremely preterm births (22-27 weeks), moderately preterm births (28-33 weeks), late preterm births (34-36 weeks), and early term births (37-38 weeks).
The median age of the 4 million-plus individuals included in the study was 22.5 years, and there were 85 million person-years of follow-up. Among this entire cohort, preterm birth age was associated with elevated risk of heart failure at any age vs full-term birth (39-41 weeks):
- Younger than 1 year (adjusted HR [aHR], 4.49; 95% CI, 3.86-5.22)
- Aged 1 to 17 years (aHR, 3.42; 95% CI, 2.75-4.27)
- Aged 18 to 43 years (aHR, 1.42; 95% CI, 1.19-1.71)
When stratifying by each measure of gestational age among the adult cohort, the risks remained elevated, as did the incidence of heart failure (per 100,000 person years), but both measures dropped with the longer gestational periods:
- Extremely preterm births (HR, 4.72; 95%CI, 2.11-10.52); 31.7 cases
- Moderately preterm births (HR, 1.93; 95% CI, 1.37-2.71); 13.8 cases
- Late preterm births (HR, 1.24; 95% CI, 1.00-1.54); 8.7 cases
- Early term births (HR, 1.09; 95% CI, 0.97-1.24); 7.3 cases
The incidence of heart failure among full-term single births was 6.6 cases per 100,000 person-years in comparison. This association was seen even after “excluding persons with structural congenital cardiac anomalies,” the authors noted.
Male and female participants also had similar case totals of heart failure stemming from a preterm birth, preterm infants were more likely to be born to mothers either younger than 20 years or 40 years and older, and most preterm births in the study were first in birth order.
An important distinction the authors add is that the greater risk of heart failure among those aged 18 to 43 years may be linked to family histories of heart failure and preterm birth, whereas this is not the case for individuals with young-onset heart failure.
All diagnoses of heart failure were identified by International Classification of Diseases, Eighth Revision, Ninth Revision, and Tenth Revision codes, and the entire study cohort was followed up with from their earliest heart failure diagnosis after birth through the end of the study period. Variables adjusted for included birth year, sex, birth order, family history of ischemic heart disease, and maternal factors such as age, education level, smoking status, and diabetes history before delivery.
“To our knowledge, this is the largest population-based study of preterm birth in association with heart failure risks and the first to examine such risks into mid-adulthood or include co-sibling analyses,” the authors concluded, with study strengths that included the large national cohort design, highly complete nationwide birth and medical registry data, and the large sample size.
Their findings indicate a possible long-term need for clinical follow-up among adult survivors of preterm births, with monitoring for heart failure one of the focus areas, especially with the median age of heart failure onset dropping, they added.
This article was originally published on AJMC.
1. Crump C, Groves A, Sundquist J, Sundquist K. Association of preterm birth with long-term risk of heart failure into adulthood. JAMA Pediatr. April 5, 2021. Epub ahead of print. doi:10.1001/jamapediatrics.2021.0131