LISBON — The high long-term death rates in women who have had one episode of severe preeclampsia suggest a strong link with cardiovascular disease in an analysis of more than 600,000 Norwegian women.
Integrating data from the Norwegian national registries for birth and for death showed that women who had one case of severe preeclampsia were nearly three times more likely to die in the long term and eight times more likely to die from cardiovascular disease, compared with women who had a term delivery and no preeclampsia, Dr. Rolv T. Lie reported at the 15th World Congress of the International Society for the Study of Hypertension in Pregnancy.
The eightfold increased risk of cardiovascular disease death was “stunning,” said Dr. Lie, an epidemiologist at the University of Bergen (Norway). It suggests that both preeclampsia and cardiovascular disease occur because of a single underlying predisposition, or that serious preeclampsia results in long-term cardiovascular complications. “They're not independent. There has to be a common pathophysiology,” he said.
His initial analysis dealt with the 626,000 women who had their first delivery during 1967–1992. Subsequent mortality and cause of death were tracked through 1992.
During follow-up of up to 25 years, women who had a term delivery and no preeclampsia had a 0.8% mortality rate. Those who had preeclampsia and a preterm delivery (a marker for early and more severe preeclampsia) had a 2.3% mortality rate. When adjusted for the women's ages and the calendar year they gave birth, severe preeclampsia was linked with a statistically significant, 2.7-fold increased risk of death.
In addition to the much higher rate of cardiovascular death, women with severe preeclampsia also had a fivefold increased risk of death from stroke.
A more recent analysis used data collected through 2004, which allowed for up to 35 years of follow-up. It also allowed death rates to be analyzed for the first 10 years after delivery and for the subsequent 10 years, which gives some insight into the persistence of the mortality effect of severe preeclampsia.
The analysis showed that the women who had experienced serious preeclampsia had a lower mortality risk in the period 10–20 years after the episode, compared with during the initial 10 years following the pregnancy. This may mean that mortality risk from severe preeclampsia diminishes with time, or it may just mean that deaths due to other causes were diluting the effect, Dr. Lie said.