Reduced Mortality for Women Undergoing Assisted Reproduction Likely Due to "Healthy Patient Effect"
Although assisted reproductive technology has been associated with decreased mortality, few studies have assessed this relationship.
Reduced mortality has been reported among women undergoing treatment with assisted reproductive technology (ART), but this survival advantage appears to most likely be a selection rather than a biological phenomenon, according to new research findings published in the American Journal of Epidemiology.
Prior epidemiologic research has reported that ART treatment is associated with lower mortality; however, because good health is a prerequisite for this treatment, this association may simply reflect what is known as the “healthy patient effect.” Conversely, it could also mirror a beneficial biological effect of ART treatment on survival.
In the current study, the investigators explored the impact of relevant selection factors on the association between ART treatment and mortality in women undergoing this treatment.
The cohort included nearly 43,000 women who were treated with ART in fertility clinics in Denmark from 1994 to 2009, age matched with a control group of approximately 205,000 women from the general population and followed until 2010.
At the end of follow-up, 79% of ART-treated women and 83% of controls had given birth to at least one child. A total of 2041 women had died: 235 in the ART-treated group (0.6%) and 1806 in the control group (0.9%). Mortality risk was lower among ART-treated women within the first 2 years following treatment, even after adjusting for confounders (HR=0.68; 95% CI: 0.63-0.74), but no difference was observed after 10 years (HR=0.92; 95% CI, 0.79-1.07).
These findings show that the “survival advantage among untreated women disappears over time, and that ART-treated women have a markedly reduced risk of death from external causes, which is very unlikely caused by biological differences,” conclude the authors.
Vassard D, Schmidt L, Pinborg A, et al. Mortality in women treated with assisted reproductive technology treatment - addressing the healthy patient effect [published online May 29, 2018]. Am J Epidemiol. doi: 10.1093/aje/kwy085