Caroline Helwick

February 08, 2016

ATLANTA — Rates of primary cesarean delivery vary by hospital laborist, even in the same institution, according to findings presented here at the Society for Maternal-Fetal Medicine 2016 Pregnancy Meeting.

"I was shocked, honestly, to see these rates vary from 12% to 36% in the same model," said lead investigator Torri Metz, MD, from the Denver Health Medical Center.

"The success of the laborist care model may be dependent on both the care model itself and the individual laborist," she explained. "Our findings highlight the impact of individual physician decision-making on the overall cesarean rate."

Dr Metz and her colleagues evaluated the rates of cesarean delivery for laborists at one hospital. They used the American Congress of Obstetricians and Gynecologists definition of a laborist — an obstetrician–gynecologist employed by a hospital to manage laboring patients and attend to obstetric emergencies.

Previous studies have evaluated the laborist model as a means of reducing rates of primary cesarean delivery, which have been rising in the United States.

The concept is plausible because laborists are more available than a patient's regular obstetrician, and they have expertise in labor management, said Dr Metz. However, when the performance of laborists has been assessed, results have been mixed, she reported.

Her team hypothesized that the success of the laborist model in reducing rates of cesarean delivery reflects the decisions of individual laborists, rather than the care model alone.

The retrospective cohort study involved all nulliparous women with no contraindication for vaginal delivery who delivered a term cephalic singleton at the Denver Health Medical Center — an academic safety-net hospital — from 2007 to 2014.

I was shocked, honestly, to see these rates vary from 12% to 36% in the same model.

The investigators calculated the rate of primary cesarean delivery for each of the 20 laborists.

Of the 22,036 deliveries in the study cohort, 4139 were cesarean, for an overall rate of cesarean delivery of 18.8%. Among the 20 laborists, who performed 2224 of these deliveries, the rate was 24.1%.

Rates of cesarean delivery were divided into tertiles. Laborists with the lowest rates managed 599 of the 2224 women, those with medium rates managed 951, and those with the highest rates managed 714.

A single-institution study "reduces extraneous factors that may influence individual cesarean delivery rates," said Dr Metz. "Even within a care model where specialists are available all the time and the women they are managing are the same and are randomly allocated, we still see a huge variation in cesarean delivery."

Huge Variation in Cesarean Delivery Rates

Rates of cesarean delivery for individual laborists ranged from 12.5% to 35.9%. This constitutes a 2.9-fold variation between the highest and lowest tertiles (P < .001), Dr Metz reported.

Among the tertiles, there were no significant differences in the demographic and clinical characteristics of the women, the indications for cesarean delivery (fetal status, arrest disorders, elective, other), or short-term neonatal outcomes.

"We adjusted for patient-level factors known to be associated with cesarean delivery, including hypertensive disease, gestational age at delivery, race, and maternal age, and we found that the difference between the highest and lowest individual laborists actually expanded to 3.58-fold (P = .0265)," Dr Metz added.

Apgar scores below 7 at 5 minutes were 3.07% in the lowest tertile, 3.61% in the medium tertile, and 3.70% in the highest tertile. The only case of neonatal encephalopathy occurred in the lowest tertile.

No Notable Differences in Provider Characteristics

After the presentation, Dr Metz was asked about differences in provider characteristics. None were identified, she reported. For example, she said, there was no correlation between overall delivery volume and cesarean delivery rate. And individual provider characteristics were not predictive of cesarean delivery in a binomial regression model that included years in practice, sex of the laborist, and whether the provider was a maternal–fetal medicine specialist or a general obstetrician–gynecologist.

All laborists received a straight salary, she added, so they were not financially incentivized toward cesarean delivery.

However, she acknowledged, provider traits that are "hard to capture" could explain some of the differences.

Strident Discussion

Interestingly, only 20% of the laborists wanted to know their rate of cesarean delivery when offered that information.

Laborists should not be asked if they want their rates, said Michael Socol, MD, the Thomas J. Watkins Memorial Professor of Obstetrics and Gynecology at the Northwestern University Feinberg School of Medicine in Chicago.

Instead, cesarean delivery rates should be distributed to all faculty, and then results should be followed to see if "this feedback changes behavior," he said.

Dr Metz said she agrees. "There are opportunities for intervention," she explained. "Some studies have shown that by publicizing rates, you reduce cesareans."

"We will be looking at that," she added.

Dr Socol pointed out that "in this world of transparency, these findings are not something to be laughed at. Hospitals may someday have to report this information."

Dr Metz and Dr Socol have disclosed no relevant financial relationships.

Society for Maternal-Fetal Medicine (SMFM) 2016 Pregnancy Meeting: Abstract 28. Presented February 4, 2016.


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