Friday, July 25, 2008

Garbage in, garbage out; Murphy and Fullerton's "optimality" index

We have been discussing Murphy and Fullerton's "Optimality Index" in the comments section, and I'd like to promote the discussion to the main page.

Drs. Murphy and Fullerton created the Optimality Index. Rather than looking at adverse outcomes, Murphy and Fullerton believe that childbirth can best be analyzed by comparing individual outcomes with optimal outcomes. The prefer this approach because it deliberately incorporates specific beliefs about what constitutes optimal care. For example, traditional medical studies would consider the birth of a healthy baby to a healthy mother the optimal outcome; the Optimality Index would subtract points from a perfect score because, in their view, having an epidural is a non-optimal outcome.

The following will cause you to lose points on the "optimality index":

biophysical profile
prescription medication of any kind
any medication in labor
continuous fetal monitoring
directed pushing
less than 45 deg. head elevation at birth
perineal laceration

But that's not even the worst part. The worst part is that any of these events are coded as EQUIVALENT to:

cord prolapse
severe pre-eclampsia
shoulder dystocia
intraventricular hemorrhage
renal failure
neonatal seizures

So if you have an NST, biophysical profile, induction, any medication in labor, an epidural,continuous fetal monitoring, directed pushing, less than 45 deg. head elevation at birth, a perineal laceration and a LIVE BABY your optimality index is 47.

If you have none of those things and a DEAD BABY, your optimality index is 56.

Murphy and Fullerton were quite forthright about their aims in their first paper about the optimality index, Measuring outcomes of midwifery care: development of an instrument to assess optimality:

"Research on the outcomes of midwifery care is hampered by the lack of appropriate instruments that measure both process and outcomes of care in lower risk women. This article describes an effort to adapt an existing measurement instrument focused on the optimal outcomes of care (The Optimality Index-US) to reflect the contemporary style of U.S.-based nurse-midwifery practice..."

The optimality index has two primary explicit motivations and one primary implicit motivation:

First, it is designed to give far MORE weight to process than to outcome; a perinatal death is equivalent to having an epidural.

Second, it is designed to measure how closely a birth adheres to the values of midwives.

Third, it implicitly dismisses the opinion of the mother by assigning it no value at all.

Ultimately, the optimality index tells us nothing about birth, but a great deal about the midwives who designed it and the midwifery organizations who support it: It does not matter very much to them whether the baby lives or dies. Conforming to the ideals of midwifery is very important to them. The mother's opinion, needs and desires are meaningless.

Murphy and Fullerton should be embarrassed for proposing such an index and midwifery organizations should be embarrassed for supporting it. Personally, I think the name should be change from "Optimality Index" to "Inanity Index".

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