Risk-adjusted Primary Cesarean Delivery Rates And Quality Assessment Of Obstetric Care

Objective: The purpose of this study was to explore the risk factors of cesarean delivery (CD) using a logistic regression model, and to calculate risk-adjusted primary CD rates comparing with observed primary CD rates, to evaluate the quality of obstetric care in our obstetrics unit.Material and methods: The study population consists of all live births in the First Affiliated Hospital of Kunming Medical College between 1 January 2002 and 30 April 2007. During the study period, 8155 infants were delivered, after exclusion (432 births), remaining 7723 births for final analysis. The independent variables which would likely be important in determining the risk for a CD were maternal age, nulliparity, maternal race, maternal occupation, maternal education, and the trimester that prenatal care began, multiple pregnancy, gestational age, maternal medical conditions and intrapartum complications. A multivariate logistic regression model of characteristics independently associated with CD was developed with the use of a random 25％sample of the data, the model was validated on the 75％portion of the data that were not used to build the model and an A statistic was calculated, the A statistic refers to the area under the receiver operating characteristic curve, A statistic above 0.7 indicate acceptable discrimination. Using the model, the probability of a CD was determined for every patient in the database. The risk-adjusted primary CD rate for a hospital in each year was calculated by an average of the CD probabilities of each patient who delivered at the hospital in each year. We then compare the two rates.Results: 1. Nulliparity, maternal age, multiple pregnancy, maternal medical conditions and intrapartum complications were the risk factors of CD, preterm was protective against CD; nulliparity, maternal age≥35 age, multiple pregnancy, moderate and severe maternal medical conditions, placental previa and breech/malpresentation, were increased CD risk. 2. Both the observed primary CD rates and the risk-adjusted primary CD rates were decreased over the past 6 years, in 2006～2007, the observed primary CD rate was in the upper of the 95％CI of the risk-adjusted primary CD rate, the observed primary CD rate was 38.82％.Conclusions: 1. Nulliparity, maternal age≥30age, maternal education, multiple gestation, maternal medical conditions and intrapartum complications were the risk factors of CD, preterm was protective against CD. 2. Both the observed primary CD rates and the risk-adjusted primary CD rates were decreased over the past 6 years, reflecting quality of obstetric care of our hospital rose step by step. 3. Risk-adjusted primary CD rate was a good standard evaluated quality of obstetric care.