Medical Lessons from the Big Mac: Startups thrive by treating specific illnesses or conditions

Doctors, hospitals, and insurers are pursuing strategies that depend on caring for a narrow range of patients or on mastering a small slice of treatments. This is the latest step in health care's rapid evolution, promising to alter once more the way Americans are treated for a broad range of medical conditions. With professional management and close coordination of services, these specialized entities can lower costs and produce better medical results. This notion fights decades of health-industry tradition. Most managed-care advocates still prefer to see generalized "gatekeepers" control treatment decisions, limiting access to expensive cardiologists and podiatrists.