You have a complex structure in the sentence of concern in which the subordinate noun clause ‘that there are big problems with poverty’ acts as the object of the verb ‘reminded’. Here’re some examples: The mother reminded the child that it’s bedtime. She reminded me that I had forgotten her birthday.
In the proposed sentence, you try to use the phrasal verb ‘reminded sb of sth’ to express the same meaning. So, instead of the complex sentence, you turn it into a simple one ‘Katrina reminded them of big problems with poverty.’
Both sentences are fine. Depending on the emphasis and the writing style, you may use either.
Student or Learner