Setback and Worsening of someone's condition

Setback noun - A change in status for the worse usually temporarily.

Worsening of someone's condition and setback are semantically related. In some cases you can use "Worsening of someone's condition" instead a noun "Setback".

Setback and worsening of someone's condition are semantically related. You can use "Setback" instead a noun phrase "Worsening of someone's condition".