The phrase "most concerning to" is correct and usable in written English.
You can use it as an adjective to describe which of a group of things you are most concerned about. For example: "Of all the recent changes, the most concerning to me is the alteration to the work schedule."
What's most concerning to you when you look at that landscape?
Most concerning to Bowser, who announced in March that she is running for mayor, was the finger-pointing.
But most concerning to officials was a drop in coverage among the youngest children — those under 5 — who are at highest risk for serious flu complications.
Most concerning to his doctor was that he wasn't holding down fluids or going to the bathroom — a sign of dehydration, which can make it harder for the body to defend itself against an infection.
Their report says all the current indicators show there has been a rapid deterioration in standards of safety over the past year or so: "Most concerning to us is that, since 2012, there has been a 38% rise in self-inflicted deaths, a 9% rise in self-harm, a 7% rise in assaults and a 100% rise in incidents of concerted indiscipline".
CLINTON: Judy, I think that the best analysis that I've seen based on Senator Sanders plans is that it would probably increase the size of the federal government by about 40%, but what is most concerning to me is that in looking at the plans -- let's take healthcare for example.
This business of slow strangulation of the rule, with no opportunity afforded parties most concerned to be heard, would be indefensible in any circumstances.
Early non-cognitivists seem most concerned to defend metaphysical and epistemic commitments incompatible with a realist interpretation of moral claims.
What are the issues of most concern to you?
The disease of most concern to humans is rabies, which is transmitted in saliva via bites.
The timing of the alleged hacking will cause most concern to Rupert Murdoch's News International.
