Iatrogenic means "caused by a physician/doctor." Typical usage would be in reference to an injury, illness, or death; I can't parse what you mean by "[t]he NHS is iatrogenic"
I'm riffing on what Theil said in the article. The NHS considered as a system in it's present condition makes some people sicker than when they came in much as routine prescribing of fentanyl is held to have triggered americas addiction crisis in working poor. For different reasons. Delay, and use of outdated treatments because of health economics, and because of problems like c.difile and golden staph in the residential hospital system.