For immediate release
Tuesday, Aug 8, 2006
12:01 a.m. EDT

 

Contact:
Christopher Fleming
301-347-3944
cfleming@projecthope.org

In Areas Where Cesareans Are More Frequent, The Operation Is Performed On Less Appropriate Patients

Counties Could Reduce High Cesarean Rates
Without Increasing Maternal Or Infant Mortality

Bethesda, MD -- In counties where a greater percentage of babies are delivered through cesarean section, physicians extend the procedure to patients who benefit less from receiving a cesarean.

A study published today on the Web site of the journal Health Affairs found great geographic variation in the use of cesareans, mostly unrelated to patients’ medical conditions. Rather, the study found that nonmedical factors such as the density of providers and local medical malpractice pressures drove variation in the cesarean rate. The study also determined that counties performing cesareans more often could reduce the rate of this expensive and hazardous intervention by three to five percentage points without increasing maternal or newborn mortality.

“Our finding that physicians in areas with higher cesarean rates are performing procedures that are of decreasing medical value to patients has important policy implications,” write lead author Amitabh Chandra, an assistant professor of public policy at Harvard University’s John F. Kennedy School of Government, and colleagues. “Cesareans are an expensive intervention, with an average cost in 2003 of $12,468 -- twice the cost of the average vaginal birth ($6,240). There is also evidence that women undergoing a cesarean delivery are at much higher risk for rehospitalization for uterine infection and obstetrical surgical wound complications.”

Cesarean Rates Affected By Socioeconomic Factors,
Malpractice Liability Environment, Provider Availability

The cesarean rate in the United States is much higher than the rate in other countries, and bringing the U.S. rate down is one of the goals of the Centers for Disease Control and Prevention’s (CDC’s) Healthy People 2010 initiative. Within the United States, Chandra’s team found, the cesarean rate varies greatly from place to place, even after taking patients’ risk profiles into account. In large U.S. cities, for example, for normal-birthweight (NBW) babies (those weighing more than 2,500 grams at birth), rates ranged from 12.5 percent in Minneapolis to 25.6 percent in Miami. These differences were not accounted for by birth characteristics but were driven in part by the local medical malpractice environment and the density of providers in the area.

Differences in patient profiles explained only 8.6 percent of the geographic variation in the cesarean rate for NBW babies and only 22.7 percent of the variation for low- and very-low-birthweight (L/VLBW) babies (those under 2,500 grams at birth). Socioeconomic factors -- such as average income, education levels, and the percentage of county residents who are white -- explained 27.3 percent of the variation for NBW babies and 11.3 percent for L/VLBW babies. The local medical malpractice environment, as measured by average malpractice premiums and the number and size of malpractice payments, accounted for 14.8 percent of the variation in cesarean rates for NBW babies and 13.9 percent for L/VLBW babies. County-level provider density -- as measured by the number of physicians in relevant specialties per birth and the number of neonatal intensive care beds per birth -- accounted for 8.8 percent of the variation in cesarean rates for NBW babies and 9.3 percent for L/VLBW babies.

For babies in both weight groupings, almost half of the geographical variation in cesarean rates -- 40.5 percent for NBW babies and 42.8 percent for L/VLBW babies -- was left unexplained after all of these factors were accounted for. “This unexplained variation [if unrelated to patient and area characteristics] could be labeled as the ‘practice style’ of an area,” explain Chandra and his coauthors, Notre Dame assistant professor of economics Kasey Buckles and UCLA associate professor of public policy Katherine Baicker.

Physicians In More-Aggressive Areas Performing Cesareans On Healthier Patients, Could Do Fewer Cesareans Without Increasing Mortality

Chandra and colleagues hypothesize that physicians in counties with higher cesarean rates were practicing “flat-of-the-curve medicine” -- that is, performing cesareans on patients for whom the procedure was relatively less appropriate. To test this proposition, they constructed a measure of the medical appropriateness of each cesarean birth. This measure was the probability that the typical obstetrician would perform a cesarean delivery in that case, based on the patient’s prebirth characteristics.

They found that in areas where the cesarean rate was higher, this measure of medical appropriateness tended to be lower, suggesting that physicians in more-aggressive counties were in fact performing cesareans on less appropriate, relatively healthier patients. “Physicians rank patients on a distribution of clinical appropriateness and work their way down that distribution,” explain Chandra and coauthors. “The point at which they stop in that distribution is affected by nonmedical factors such as provider capacity, malpractice liability, and local physicians’ opinion.”

Finally, the authors found that in counties where cesareans were performed less often, maternal and infant mortality were not higher than in counties where the cesarean rate was higher. Even a three-percentage-point reduction in the cesarean rate for NBW babies and a five-percentage-point reduction for L/VLBW babies were not associated with increased maternal or infant mortality.

Chandra and coauthors are skeptical that patients’ preferences play a sizable role in explaining variations in county cesarean rates, and they point to variation in the cesarean rates across relatively similar counties. They also note the considerable importance of factors such as provider density and malpractice pressure in affecting cesarean rates across counties. While the researchers say that there has probably been an increase in patient demand for elective cesarean delivery, they note that their analysis already accounts for the principal correlates of these preferences: demographics and income and education levels. Finally, they note that in general, patients’ satisfaction with medical care is uncorrelated with the intensity of medicine practiced in an area.

You can read the article by Chandra, Buckles, and Baicker at http://content.healthaffairs.org/cgi/content/abstract/hlthaff.25.w355

ABOUT HEALTH AFFAIRS:

Health Affairs, published by Project HOPE, is the leading journal of health policy. The peer-reviewed journal appears bimonthly in print with additional online-only papers published weekly as Health Affairs Web Exclusives at www.healthaffairs.org.

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©2006 Project HOPE–The People-to-People Health Foundation, Inc.