On-demand Health Care Is as Easy as Ordering a Pizza

What’s new: At a time when groceries, taxis and other goods and services are just a smartphone touch away from showing up at consumers’ doorsteps, America’s on-demand economy is booming. And health care services are a big part of that growth.

An ever-widening array of companies now provide on-demand services ranging from sending a doctor or a nurse practitioner to a patient’s home or workplace to treat nonemergency problems to providing intravenous treatment for conditions like hangovers and food poisoning to sending a trainer and fitness equipment to customers’ homes.

This rapidly growing market niche is part of a larger national trend for on-demand services, an economy worth an estimated $75 billion in 2017, according to...