It’s no surprise that medical marketing spending has skyrocketed in the past 20 years. And while marketing to physicians continues to consume the lion's share of the almost $30 billion spent overall, direct-to-consumer marketing is catching up.

Medical marketers spent $29.9 billion to get their messages in front of healthcare providers and consumers in 2016, up from $17.7 billion in 1997, according to a new survey assessing 20 years of industry marketing spending, published this week in the Journal of the American Medical Association. Of the 2016 total, $20.3 billion was spent marketing directly to physicians, which was up from $15.6 billion in 1997. However, it was DTC that had the biggest percentage increase: from $2.1 billion, or 11.9% of all medical marketing, in 1997 to $9.6 billion, or 32% of total spending, in 2016. Marketing to healthcare professionals once accounted for 88% of the medical promotional spending 20 years ago, but it now accounts for only 68%.

Why? Because DTC works, study co-author Steven Woloshin, a physician and Dartmouth professor, said.

"There’s evidence when you reach out to consumers, they’re more likely to choose advertised drugs even when there are good effective lower-cost alternatives. So it’s effective. It’s also a way to get around doctors, not just for drugs but for services, too," he said.

Prescription drug advertising as part of the study’s total DTC tally increased from $1.3 billion to $6 billion. The study categorized DTC as not only branded drug and general awareness advertising, but also health services advertising, which included hospitals and dental, cancer and mental health centers, and lab test advertising.

Woloshin and fellow author and physician Lisa Schwartz initiated the study at the request of JAMA as experts in the field, having studied medical marketing for years. The 20-year time frame allowed them to not only quantify the promotions in both dollars spent and number of ads over the past two decades, but also look at the related consequences and regulations.

What they found, as the study notes, was that "despite the increase in marketing over 20 years, regulatory oversight remains limited."

Several issues have led to the oversight problem, including time-stretched and small staffs at the FDA, as well as a proliferation of medical advertising that needs to be reviewed. Thanks in part to the effectiveness of DTC advertising, as well as new digital channels on which to promote products and services, the number of promotional pieces submitted for review to the FDA has gone from around 30,000 in 1997 to almost 100,000 in 2016.

As part of the study, which JAMA released online in full with charts and supplemental material, Woloshin and Schwartz came up with a list of suggestions to support responsible medical marketing. Those included specific ideas to strengthen FDA regulations, limit industry influence and increase transparency, drug fact boxes and potentially limiting DTC for new drugs until benefits and risks become more clear over time.