Some U.S. FDA warning letters are mostly about documentation, but the key consideration in the widely publicized Dec. 9 FDA warning letter to Dublin-based Medtronic plc seems to be whether Medtronic had a proper understanding of the risk created by malfunctioning infusion pump retainer rings. That difference of opinion regarding risk took a significant bite out of the company’s shares and boosted the fortunes of its rivals in the diabetes space, a cautionary tale regarding the hazards associated with a failure to understand how the FDA sees the risk of device malfunction. The FDA had reported in October 2021 a pair of recalls of Medtronic’s Minimed insulin pumps, although one of the issues cited was related to cybersecurity concerns. The two recalls affected nearly half a million units combined, and could have significantly affect access for some patients.