However miraculous an outcome any surgical or other heroic intervention may achieve, doctor and patient alike would surely agree that the better alternative is always prevention. So would insurers: they know that effective disease management—efforts to help chronically ill patients follow a treatment plan and to spot problems early—could save them enormous amounts of money every year. Specialists estimate, for example, that more than half of all hospital admissions and sick days linked to asthma and about half of the major complications linked to diabetes (such as amputations, blindness, and stroke) could be avoided with better monitoring and care. One German study showed that medical costs for a diabetic who didn’t suffer complications came to around €2,000 ($1,760) a year, while annual medical costs when complications developed exceeded €5,000.

Disease-management plans are nothing new, though to date most have failed because they were too costly. But emerging technologies that support the patient-management process could change all that. A full program can help coordinate care, encourage patients to follow their treatment plans, and provide warning as soon as problems develop. Germany is likely to be a test bed, since its government plans to compensate insurers for more of the cost...