Dr. David Meltzer, an associate professor at the University of Chicago who was the study author, said since the 1980s, doctors and patients have been encouraged to share decision-making to enhance patient satisfaction, improve health outcomes and even lower costs.
However, the study, published in Internal Medicine, found patients who wanted to participate in their medical decisions ended up spending more time in the hospital and the cost of their hospital admission increased by an average of $865.
"The result that everyone would have liked, that patients who are more engaged in their care do better and cost less, is not what we found in this setting," Meltzer said in a statement. "Patients who want to be more involved do not lower costs. Patients, as consumers, may value elements of care that the healthcare system might not."
Meltzer and researchers approached all patients admitted to the University of Chicago's general internal medicine service from July 2003 to August 2011. Almost 22,000 people, about 70 percent of those asked, completed a wide-ranging 44-question survey.
The key multiple-choice item for this study was: "I prefer to leave decisions about my medical care up to my doctor." More than 37 percent of patients definitely agreed, one-third somewhat agreed, and a little less than one-third somewhat or definitely disagreed.
"Was I surprised?" asked Meltzer. "I wasn't shocked. It could have gone either way. Our results suggest that encouraging patients to be more involved will not, alone, reduce costs."
Although this was a large study, it might not apply in every setting, the authors cautioned.
Three-quarters of the patients in the study were black, more than half had a high school education or less and nearly 80 percent were insured by Medicare or Medicaid or had no insurance.