Summary List PlacementIn digital health, startups are soaring. As of May, there had been more than 50 mergers and acquisitions since the start of 2021, on track to surpass the record in 2015, according to data compiled by Rock Health, a digital-health fund and advisor, and shared with Insider. Nearly 20 have gone public through initial public offerings or reverse mergers since January 2020, compared with just nine for the three previous years, that data shows. It's a symptom of the US healthcare system's growing pains.