WEDNESDAY, March 30 (HealthDay News) -- When it comes to taking advantage of Internet-based medical information in the form of physician-provided online "personal health records," some American patients are more plugged in than others, new research reveals.

Differences in race, income and age all affect the likelihood that patients will log on to check out their own health history, the study shows, with patients who are white, older, and/or wealthier more likely to request access to their online medical history.

"It's really probably just been in the last three or four years that usage has really begun to take off," noted study co-author Dr. David W. Bates, chief of the division of general internal medicine in the department of medicine at Brigham and Women's Hospital in Boston. "And it's growing very fast, and should continue to grow really rapidly. But the bottom-line is that a digital divide does exist in terms of who tends to start using online personal health records," Bates said.

"But the good news is that once people actually start using them, the level of use is basically the same for all patients, regardless of socioeconomic status and race," he added.

Bates, who is also the medical director of clinical and quality analysis at Partners HealthCare System in Boston, and colleagues report their findings in the March 28 issue of Archives of Internal Medicine.

Personal health records are an Internet-based set of tools that allow people to review lab-test results and communicate by email with their health care providers, among other things.

The Obama administration and many health care advocates have been pushing online medical records as a way to make health care easier and more reliable, and the authors note that more than 70 million Americans are now estimated to have access to some form of their online medical history.

That said, less than 10 percent of Americans appear to be using electronic medical records, with almost half saying they're not even clear if their doctor actually offers access, according to a Harris Interactive/HealthDay survey of more than 2,000 American adults.

The current investigation found that 43 percent of more than 75,000 patients living in the northeastern United States who had been seen between 2007 and 2009 at a clinical practice that offered personal health records had, in fact, signed up for (or "adopted") access to their doctor's system.

But upon closer look, the personal health record sign-up picture revealed considerable disparities. For example, blacks and Hispanics were only half as likely to sign up for personal health record access compared with white patients, the authors noted, and the wealthiest patients were 14 percent more likely to initiate personal health record use than the poorest patients.

Patients over the age of 65 were more likely to sign up than those between 18 and 35, as were those juggling more than one serious health issue. However, those who visited their doctor with greater regularity were actually less likely to sign up for personal health record access.

Among those who did sign up for access, just over half were categorized as "very low users" (logging in once at most in the prior two years), while a little over one-quarter were deemed "high users" (logging in 10 or more times).

Older patients, between the ages of 51 and 65, constituted the largest slice of the high-user group, they found, accounting for four in 10 among such patients.

But other personal health record usage patterns tell a more complicated story.

For example, income level had no effect on how much patients used the system once they were signed up. Similarly, although seeing a physician more often was linked to lower sign-up rates, it was also linked to higher personal health record use rates among those enrolled.

Among those who accessed personal health records, 70 percent made use of the system's patient-physician messaging feature infrequently. Among those who did, questions about care and requests for drug refills were the most popular subjects, each accounting for about one-third of messaging. Doctor referrals was another popular messaging topic, followed by address corrections and billing.

Bates and his associates were unable to say exactly what seems to be driving the differences in personal health record adoption and use, calling for more research on the subject.

"But there's already increasing evidence that using an online health record like this should improve the patient experience and quality of care," Bates said. "It's just very helpful to go and look at your lab tests at your leisure. And most providers believe that it's really to the patient's advantage to be more informed about the care they're getting," he added.

"So it's important to figure out why a lot of people haven't been doing this yet," Bates said.

Meanwhile, Erin Stevenson, a senior digital health care consultant for Redwood Medical Consulting in Bayside, Calif., sees a bright future for online personal health records, despite some patient hesitancy.

"Twentysomethings tend to take their health for granted and have better things to do, so they're not using it a lot. And poverty, which often mixes with race, is a predominant reason people don't log on, because folks who are busy and focused on just scraping by and surviving see it as a luxury they just can't swing," Stevenson observed.

"So it's the middle and upper classes, and folks who are 30 and up who are serious about their health who are using this to begin with," Stevenson noted. "It gets tricky among those mid-50s and up, because then you get into people who are not very computer literate. But people who do use it report back to their doctors that they like it. And word of mouth matters. So really we're probably going to see use going up, even doubling among the plus-30 folks over the next two to three years, as people start talking about the portal process to their friends."

More information

For more on electronic health records, visit the U.S. Centers for Disease Control and Prevention.