Tuesday, June 15, 2010

How Vision Forum "Lies with Statistics" to Prove that They are Special to God: Women with Ectopic Pregnancy Consigned to Die


Please see my post on the No Longer Quivering Blog concerning Samaritan Ministry’s support of the Vision Forum position on ectopic pregnancy, something Vyckie entitled, “Vision Forum, Samaritan Ministries Take Extreme “Pro-Life” Position on Ectopic Pregnancies.”

LATE NOTE:  For math geeks, please see my disclaimer at the bottom of the page.

On the first day of my statistics class in college, the instructor held up a book that was not our assigned text, an old classic from the 1950s entitled “How to Lie with Statistics.”  Whenever he introduced a new topic, the instructor also presented an example of common mistakes made by many people, failing to appreciate the traps one can fall into when trying to prognosticate.  And my own research was good enough to have been the only undergraduate invited to present their research project at the Nursing Honor Society’s regional meeting in 1987.  And I continue to review data and participate in peer review within toxicology, having co-authored published research in this related field.  I’ve won two "Young Scientist" research awards as coauthor from TIAFT.  All that to say that I know a little bit about statistics -- particularly health care statistics after more than 25 years in the field.   I don't know that Vision Forum intends to lie with statistics, but they end up making classic and ignorant errors which results in the manipulation of their followers. (It might be an innocent result of confirmation bias.)   I think that their followers deserve informed consent.

I have not submitted this blog post for a stringent peer review, and many of these numbers are estimated.  That must be duly noted. (Peer review is vitally important when considering research information.)  I pulled this information from highly reliable sources in order to demonstrate why Vision Forum’s perception of the incidence of ectopic pregnancy does not reflect true morbidity and mortality rates in proper perspective.  I don’t really understand why Vision Forum would quote any statistics anyway if their reasons for their stance were purely axiomatic and based upon ethics.  Somehow their crunching of the numbers is not utilitarian, but mine regarding saving a mother from the life-threatening consequences of a pregnancy wherein the baby has a 0% chance of survival is seen as utilitarian?   It is dissembling at best.

Note these statistics about ectopic pregnancy displayed in the graphics.

What does all of this really mean?

In 1992, there were 108,800 ectopic pregnancies reported in the US.  98% of all ectopic pregnancies are tubal pregnancies. 

2176 of those pregnancies would statistically be non-tubal ectopic pregnancies (2% of the total number of ectopic pregnancies).

(Source:  Pregnancy-Related Mortality Surveillance --- United States, 1991—1999.  CDC.  Surveillance Summaries February 21, 2003 / Vol. 52 / No. SS-2.)

What About the Babies that Survive Ectopic Pregnancy?

The chance of a baby surviving an ectopic pregnancy is an estimated  1 in 60 million.  No tubal implantations ever survive.

This number is a “guesstimate”  for non-tubal ectopic pregnancy survival or what scientist friends of mine call a “SWAG.”  (It stands for “Scientific Wild A_ _ Guess.”)  There are so few babies that do survive, it is impossible to get truly statistically significant, reliable, and meaningful numbers that indicate how many babies survive ectopic pregnancy. All the reports are technically anecdotal only.

Kim Coghlan, a Vision Forum affiliate, reports that she has read that there are a reported 60-100 live births that have resulted from non-tubal ectopic pregnancies.  If we assume that these numbers reflect other improvements pregnancy outcome statistics, lets say that those reports have come from peer reviewed journals and reflect all cases that have been reported over the past 30 years.  (Pregnancy outcomes have improved dramatically since prior to 1970, so lets assume that these survival cases accumulated during this time period.)  If you bounce that off of our stable and current worldwide birth rate of 134 million/year, that brings the probability down to a chance of 1 in 50 million of all births.  But I’m going to use 60 million, since the physician referenced by Coghlan reported this number.

What is the significance of 60 million births?  What does this mean?

Roughly, there have been 4,020,000,000 births in 30 years throughout the world. (For the sake of this argument, based on an estimated 134 million births worldwide per year, give or take variations and population growth). 

With one baby surviving in every 60,000,000 births, one surviving ectopic live birth would occur on the earth at a mean rate of every 6.7 years.  (I did not consider the standard error of the mean, averaging out the mean number per year dispersed over 30 years.)


The babies that Vision Forum lauds face odds that would average out so that only one baby would survive a non-tubal ectopic pregnancy world wide, roughly, every 6.7 years.


How does that compare with the number of women who suffer morbidity and mortality every year as a result of tubal pregnancy?

In April 2010, the British medical journal, Lancet, published an estimated worldwide maternal death rate of 342,900 in the year 2008.  Ectopic pregnancies in developed countries are consistent with rates in the US. (They are rising like ours in the US have risen since 1970.)
(Source: Maternal mortality for 181 countries, 1980—2008.  The Lancet, Volume 375, Issue 9726, Pages 1609 - 1623, 8 May 2010  (Online posting April 2010.)
Death rates worldwide for ectopic pregnancy would total 205,740 20,574 to 308,610 30,861 deaths, as research has shown that since 1991, ectopic pregnancy accounts for 6-9% of all maternal deaths.


Let’s pick a midpoint figure and assume for the sake of clarity that 250,000 25,000 women died worldwide from complications of an ectopic pregnancy in 2008 based on the numbers from Lancet article and the 6-9% cause of death prevailing in the 1990s as determined by the CDC.   (See Addendum note below)

Kim Coghlan downplayed the incidence of ectopic pregnancy, pulling statistics that relied upon data which includes women who were treated surgically for ectopic pregnancy, life-saving surgery that she has defined as murder to argue that there are barely any deaths due to ectopic pregnancy.   I’ve found from the most reliable sources regarding vital statistics from the CDC that 55,600 women were hospitalized in 1991 in the US for ectopic pregnancy, and an estimated 250,000 25,000 women died in 2008 due to ectopic pregnancy, even with pre-emptive surgical treatment.  That’s a huge number of women.  She quotes one physician who says 70% of ectopic pregnancies don’t require treatment at all, and somehow, that’s supposed to magically negate the hard statistics on morbidity and mortality from the CDC and three peer-reviewed sources.  ?????

Samaritan Ministries republished her writings in their newsletter in 2008 to advise their members on health matters and to assist them in healthcare decision making.  I find this pretty deplorable, but how would they know that the information she presented was misleading and distorted?  Samaritan Ministries did not employ any staff or management with any training in healthcare when I investigated the matter in 2008 (though they can opt to contact a physician with whom they consult as needed).  I was trained, trained, trained to properly evaluate statistics and to defer to peer reviewed sources, never assuming that a single case study indicated anything for a population until it demonstrated statistical significance after stringent mathematical analysis.

If Vision Forum would like to follow a Luddite and pious mentality, that is their choice.  If a woman suspects or has been told that she has an ectopic pregnancy, at least this summary will be available for her to review.  The last surviving ectopic pregnancy I’ve noted took place in 2008, so we have a few years to wait until we can expect to see another one on the face of the planet.  If that woman wants to be a martyr for her already dying baby because a bunch of lawyers told her that she must, at least she has this resource to also consider, something to help her put matters into perspective. And I can rest knowing that I made the effort to put the matter into proper perspective.

For those who follow the Vision Forum mandate concerning ectopic pregnancy, maybe the outcomes will be more like those for ectopic pregnancy in the mid 1800s?
(Source for 19th Century Data:  Ectopic Pregnancy.  Author: Vicken P Sepilian, MD, MSc, Medical Director, Reproductive Endocrinology and Infertility, CHA Fertility Center  Coauthor(s): Ellen Wood, DO, FACOOG, Voluntary Assistant Professor, University of Miami School of Medicine)
How can Vision Forum honestly argue
that they are 100% Pro-Life?

LATE NOTE:  (I wanted to check with my resident expert for peer review before I posted this explanation.)

I have to address something here that I bantered around for the sake of argument to give some reference to what 1 in 60 million means.

I believe that this number is a gross exaggeration of probability. This physician did not calculate the odds correctly, and my instructor in statistics would eat his lunch. He arrives at a rough estimate based upon numbers of pregnancies bounced off of all pregnancies to figure out an incident rate. But this is not scientifically accurate.

What needs to be done to truly say anything meaningful (in terms of the rules of statistics) involves looking at the population subset in context to determine rules for that subset. What this physician is doing is making gross estimates, not determining probability. In other words, if you are going to make presumptions about probability for a subset, you have to look at the subset, not at the whole population.

He is wrong to look at all pregnancies to find probability. (I also would like to see hard data that documents these supposed 60-100 cases of ectopic pregnancies.) But assuming they do exist, to determine probability that is meaningful, you have to start with ectopic pregnancy numbers themselves.

Think about it. Ectopics occur in 0.003% of all pregnancies. We know definitively what those numbers are. We don’t have to extrapolate to arrive at them. Of that small number, 98% of those are tubal pregnancies and can never survive. What is 2% of 0.003%. It is not much.  It is from that group that the surviving babies arise.  You can't start with all pregnancies to make such generalizations about such a tiny group.

I’m to lazy to pull out the book and a calculator, but I suspect that the incidence is much greater than 1 in 60 million. It is probably more in the neighborhood of 1 in 120 million. (Lord only knows.) I think that 1:60 MIL is a gross overestimate of frequency.

That’s why it is more efficacious in the discussion to look at maternal death rates and how many deaths are attributed to ectopic pregnancy to make a rational statement about incidence. The population of deaths is larger, it can be evaluated and put to the test with mathematical tools to ensure that it is meaningful.

But I had to start somewhere…. Even with this gross overestimate, these odds are ridiculous.

17Jun10 Addendum:  Corrections in original post material noted with a strike through the error.  See this post.