title: Variation in primary cesarean delivery rates by individual physician within a single-hospital laborist model.
abstract: BACKGROUND
  Laborist practice models are associated with lower rates of cesarean delivery than individual private practice models in several studies; however, this effect is not uniform. Further exploration of laborist models may help us better understand the observed decrease in rates of cesarean delivery in some hospitals that implement a laborist model.
  
  
  OBJECTIVE
  Our objective was to evaluate the degree of variation in rates of primary cesarean delivery by individual laborists within a single institution that uses a laborist model. In addition, we sought to evaluate whether differences in rates of cesarean delivery resulted in different maternal or short-term neonatal outcomes.
  
  
  METHODS
  At this teaching institution, one laborist (either a generalist or maternal-fetal medicine attending physician) is directly responsible for labor and delivery management during each shift. No patients are followed in a private practice model nor are physicians incentivized to perform deliveries. We retrospectively identified all laborists who delivered nulliparous, term women with cephalic singletons at this institution from 2007 to 2014. Overall and individual primary cesarean delivery rates were reported as percentages with exact Pearson 95% confidence intervals. Laborists were grouped by tertile as having low, medium, or high rates of cesarean delivery. Characteristics of the women delivered, indications for cesarean delivery, and short-term neonatal outcomes were compared between these groups. A binomial regression model of cesarean delivery was estimated, where the relative rates of each laborist compared with the lowest-unadjusted laborist rate were calculated; a second model was estimated to adjust for patient-level maternal characteristics.
  
  
  RESULTS
  Twenty laborists delivered 2224 nulliparous, term women with cephalic singletons. The overall cesarean delivery rate was 24.1% (95% confidence interval 21.4-26.8). In an unadjusted binomial model, the overall effect of individual laborist was significant (P < .001), and a 2.9-fold (1.5-5.4, P = .001) variation between the cesarean delivery rates of the greatest (35.9%) and lowest (12.5%) physicians was observed. When adjusted for hypertensive disease, gestational age at delivery, race, and maternal age, the physician effect remained overall significant (P = .0265) with the difference between physicians expanding to 3.58 (1.72-7.47, P <. 001). Between groups of laborists with low, medium, and high rates of cesarean delivery, patient demographics and clinical characteristics of the population managed were clinically similar and not different statistically. The primary indication for cesarean delivery did not differ between groups. Similarly there were no differences in short-term neonatal outcomes, including Apgar scores, arterial cord blood pH, or the incidence of neonatal encephalopathy.
  
  
  CONCLUSIONS
  The 3-fold variation in cesarean delivery rates between laborists at the same institution without observed differences in patient characteristics or short-term neonatal outcomes draws attention to the impact of individual physician decision-making on cesarean delivery rates even within a laborist care model. Further exploration of the role of individual physician decision-making on cesarean rates may help to better elucidate the effect of the laborist model.
authors.affiliation: Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO; Department of Obstetrics and Gynecology, Denver Health Medical Center, Denver, CO. Electronic address: Torri.Metz@dhha.org.
authors.forename: Torri D
authors.initials: TD
authors.lastname: Metz
authors.affiliation: Department of Biostatistics and Informatics, Colorado School of Public Health at the University of Colorado Denver, Denver, CO.
authors.forename: Amanda A
authors.initials: AA
authors.lastname: Allshouse
authors.affiliation: Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO.
authors.forename: Sara A Babcock
authors.initials: SAB
authors.lastname: Gilbert
authors.affiliation: Department of Obstetrics and Gynecology, Denver Health Medical Center, Denver, CO.
authors.forename: Reina
authors.initials: R
authors.lastname: Doyle
authors.affiliation: Rocky Mountain Poison and Drug Center, Denver, CO.
authors.forename: Angie
authors.initials: A
authors.lastname: Tong
authors.affiliation: Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, CO; Department of Obstetrics and Gynecology, Denver Health Medical Center, Denver, CO.
authors.forename: J Christopher
authors.initials: JC
authors.lastname: Carey
mesh_terms: D000328:Adult; D002585:Cesarean Section / Q000706:statistics & numerical data*; D015331:Cohort Studies; D005113:Extraction, Obstetrical / Q000706:statistics & numerical data; D005180:Faculty, Medical / Q000706:statistics & numerical data*; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D006784:Hospitals, Teaching; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007748:Labor Stage, Second; D017146:Models, Organizational; D007744:Obstetric Labor Complications; D010298:Parity; D011247:Pregnancy; D012189:Retrospective Studies; D013997:Time Factors; D055815:Young Adult
keywords: Cesarean; Cesarean delivery rate; laborist; physician traits