Researchers at three U.S. practices found doctors' initial concerns about the extra time it would take to write out notes and answer patients' related questions didn't pan out.
"We were thrilled by what we learned," said Dr. Tom Delbanco, who worked on the study at Beth Israel Deaconess Medical Center in Boston.
"We had no clue that so many patients would read their notes, and that they would be both as enthusiastic and report so many clinically important changes in their behavior."
Delbanco led the study with Jan Walker, a nurse at Beth Israel.
They and other researchers implemented the program at Beth Israel, Geisinger Health System in Northeast/Central Pennsylvania and Harborview Medical Center in Seattle.
The current study involved 105 primary care doctors and more than 13,000 of their patients who participated in the trial of the system, called OpenNotes.
Over the course of a year or more, 87 percent of those patients opened at least one note and four in ten responded to a survey about their general experience.
Most patients said having access to their doctors' notes gave them more control over their care and helped them take any prescribed medications more reliably. That was all based on surveys; the researchers didn't track how often patients actually filled their prescriptions, for example.
Between one-quarter and one-third of patients still had privacy concerns about having the notes online, but 99 percent wanted to keep their access after the study ended.
Doctors, in turn, didn't report feeling bogged down or limited in their note-taking by the system. None of them elected to stop making their notes accessible after the trial, according to findings published Monday in the Annals of Internal Medicine.
In another paper published in the journal at the same time, researchers found implementing electronic health records across one California health system was linked to better monitoring and control in patients with diabetes.
But another recent study didn't report such a pattern (see Reuters Health story of May 30, 2012). Researchers at the time said that just having such tools doesn't mean they'll be used meaningfully.
Eileen Hughes, a Beth Israel patient from Jamaica Plain, Massachusetts, who was involved in the program, said she "absolutely love(s)" being able to see her primary care doctor's notes.
"I just felt like having access to her notes was just another wonderful tool for me to keep up to date on what was going on with my health, and also just to reiterate what was going on in my discussions with her," Hughes, 51, told Reuters Health.
She recently saw many different specialists before finally being diagnosed with a rare autoimmune disorder. During that process, her primary care doctor consolidated the information from those visits so Hughes could see it online.
This study isn't the first to experiment with allowing patients to see their doctors' notes - M.D. Anderson Cancer Center in Houston has made notes and nearly-full medical records available for the past few years.
Dr. Thomas Feeley, head of anesthesiology and critical care at M.D. Anderson, said the new study is in line with what he and his colleagues have experienced.
"It really just confirms that this makes sense to do. There really are no downsides to doing it - patients don't get worried, they don't get anxious about it," he told Reuters Health.
Feeley said the findings will be "very reassuring" to doctors who have considered opening up their notes but may have reservations about it. But, he said, patients will still have to speak up if they want his kind of access.
"It's not that hard to do," Feeley said. "This was probably the simplest and cheapest information technology that we've embarked on."
Delbanco said the cost of implementing such a system varies widely, partly based on whether patients already have access to some of their medical documents online or if a hospital has to start from scratch.
Walker told Reuters Health that even if health systems don't have the technology in place to allow for online note checking, they can make it policy to mail doctors' notes to patients after every visit or print them out on their way out the door.
"The idea is just to get the notes into patients' hands," she said.
SOURCE: http://bit.ly/PShmuj Annals of Internal Medicine, online October 1, 2012.