Dr. Joe Prendergast began to appreciate the power of the Internet 15 years ago, when he began using the online archives of the Library of Congress to do medical research. It was an arduous process, but it always seemed worth the hassle -- never more so than when he got a call from a partner in his medical practice in Atherton, California, a palm-shaded community near Palo Alto. "He had a patient who had a bad thyroid problem," Prendergast recalls, "and he said, 'Unless you can think of some way to help this person, we'll have to evaluate him for a heart transplant at Stanford on Monday.' "

Prendergast fired up his PC and did a search that uncovered two articles on thyroid problems, both describing radical treatments that involved new drugs. "We instituted those treatments," he says, "and, instead of being evaluated for a transplant on Monday, the patient went home on Wednesday."

It was a remarkable moment -- and what made it even more remarkable was that Prendergast isn't a heart specialist. He's a leading expert on diabetes. For the past 10 years, the treatment of diabetes has been his profession. Meanwhile, his extracurricular passion has been information technology. Eighteen months ago, Prendergast combined his profession with his passion and founded DiabetesWell, a Web and email service that uses the Internet to reinvent the way diabetics manage their disease.

Prendergast has created a "killer app" that not only saves money -- it saves lives. Diabetes affects one in 17 Americans, and the costs associated with it account for almost one-10th of the more than $1 trillion that the United States spends annually on health care. One reason why diabetes is so costly is that most of the doctors who treat it aren't experts.

"Too many people don't know how to manage diabetes," says Prendergast, 62, who has the soft-spoken, self-deprecating manner of a country doctor. "Family practitioners care for 95% of diabetics, and they don't know how to control the disease."

DiabetesWell solves that problem by enabling patients to be in constant contact with Prendergast and his staff of specialists -- six registered nurses and one physician. For members (who pay $19.95 a month after a three-month trial period), the site offers a program that includes quarterly assessments, nutrition counseling, and recommendations for diet, exercise, and medication.

New patients undergo a battery of tests that measure everything from circulation to cholesterol to Hemoglobin A1C (which measures the rate at which glucose adheres to red blood cells). Test results are then fed into a database. Once treatment gets under way, tests are administered continuously, so that Prendergast and his team can compare patient data over time.

"To Joe, diabetes is a data disease," says Regis McKenna, 60, the legendary Silicon Valley venture capitalist who bankrolled Apple and who was the original financier behind DiabetesWell. "If you get the right data, then you can manage diabetes."

McKenna speaks from experience. He has been a diabetic for the past 40 years -- and a patient of Prendergast's for the past 6 years. He lost an older brother to diabetes in the 1950s -- a death that he attributes to ignorance. "I've always been very aware of my disease," says McKenna. "But Joe corrects a lot of the notions that you have as an amateur. He'll refer you to a new study. As a result, I've become better educated about my disease."

DiabetesWell is designed to make patients smarter about diabetes. Anyone can sign up for Prendergast's "E-News," a free daily email newsletter that provides information on the latest medications, treatments, and research results. Prendergast researches and writes the newsletter himself, and he keeps it short enough to be read in 60 seconds.

How well does the service work? Today, none of DiabetesWell's 1,200 patients are on dialysis. Whereas 240 of Prendergast's patients had to be admitted to a hospital in 1992, only 10 of them had to be admitted last year. And, in terms of heart disease (the number-one killer among diabetics), none of his patients under age 65 have suffered a heart attack in the past three years.

"We sent 180 people to one cardiologist in 1992," he says. "I just got a letter from him that said, 'Did I offend you? Are you sending everybody somewhere else?' The answer is, it's over. I don't send people to the hospital anymore. Is that fun or what?"

Contact Dr. Joe Prendergast by email (jjp@diabeteswell.com), or visit DiabetesWell on the Web (www.diabeteswell.com).

Sidebar: Breakthrough Prescription

During his career as a marketing expert and venture capitalist, Regis McKenna has seen lots of innovators and lots of big ideas. He has invested his time, his reputation, and his money in some very big recent successes -- from Apple Computer to Genentech.