All Over the Map: Elective Procedure Rates in California Vary Widely


Cardiac patients in the Clearlake area are up to 10 times more likely to undergo elective invasive treatments than similar patients in the Sonoma area. This is one of dozens of examples of how the use of high-tech, expensive treatments can often be based on the practice patterns of doctors where a patient lives, rather than patient preference. While the reasons behind such variation are hotly debated, new research from the California HealthCare Foundation supports the idea that physician opinions dictate many of these decisions — at times putting patients at unnecessary risk and ultimately driving up the cost of health care for everyone.

Several new CHCF publications, available through the link below, help illustrate the issue and provide context:

  • Seven in-depth “close-ups” provide data on 13 specific procedures, including hip and knee replacement, coronary artery bypass graft surgery, angioplasty, elective induction of childbirth, and weight loss surgery.
  • An interactive map presents easy access to data on these procedures throughout California.
  • A background report, All Over the Map: Elective Procedure Rates in California Vary Widely, discusses the factors involved in variation and highlights the important role that patient input can play in decisions about treatment options.

Only elective procedures were included in the research because the rate at which they are delivered is determined by the preferences of clinicians and patients. Procedures were chosen because they are commonly performed and/or because earlier studies have shown wide geographic variation in their rates elsewhere.

Though earlier studies on geographic variation have focused primarily on Medicare patients, this analysis examines the Medicare population (both fee-for-service and managed care) as well as younger individuals enrolled in commercial plans or Medicaid or who are uninsured. The consistency of results across the over- and under-65 population makes this a significant contribution to the literature documenting geographic variation.

Examples from the findings:

  • Marysville region residents have coronary artery bypass graft surgery at 264% of the state average rate.
  • Red Bluff region residents undergo knee replacements at 200% of the state average rate.
  • Women who live in the Berkeley region deliver vaginally after having had a cesarean section at 301% of the state average rate.
  • Ridgecrest residents (in the San Bernardino area) have gall bladder surgery at 177% of the state average rate.
  • Residents over age 65 in seven of San Diego’s Hospital Service Areas undergo elective angioplasty at least 150% of the state average rate; in the Brawley region, for example, these residents undergo elective angioplasty at 211% of the state average.

“This research shows that where you live — and the health care treatment norms in a particular community — make a difference. There is distinct geographic variation with respect to the rate at which patients with similar conditions are provided certain elective procedures,” notes Maribeth Shannon, director of CHCF’s Market & Policy Monitor Program.

The analysis was done by Stanford University researcher Lawrence Baker, PhD, and the reports were written by Shannon Brownlee, MS, and Vanessa Hurley, MPH, of the New America Foundation Health Policy Program.

While some geographic variation in rates of procedures is expected due to differences in the prevalence of disease, note the authors, much of the variation seen across California cannot be explained by illness rates. Some communities in California were found to have procedure rates that were 150% of the state average while others were as high as 550% — far exceeding differences in health status. Other communities have exceptionally low rates. The analysis by Baker controlled for age, sex, race, education, income, and insurance status; in the case of heart procedures the analysis also took into account rates of heart attack and diabetes.

The authors note that for elective procedures, a patient’s own values and willingness to accept uncertainty in outcomes should be considered alongside the clinician’s recommendations. They state one way to encourage that communication is through shared decisionmaking, a formal process intended to ensure that patients are fully informed about their options.

Interviews with a CHCF expert, the lead author, and the report’s physician advisory committee members are available upon request.


About the California Health Care Foundation

The California Health Care Foundation is dedicated to advancing meaningful, measurable improvements in the way the health care delivery system provides care to the people of California, particularly those with low incomes and those whose needs are not well served by the status quo. We work to ensure that people have access to the care they need, when they need it, at a price they can afford.