From then on the patient's condition worsened gradually, but the worsening speed was slower than before the transplantation.

此后患者病情逐渐加重，但较移植治疗前进展速度明显减缓。

youdao

This summer vacation, unfortunately, I came down with hoarseness due to certain reason. Worse still, it worsened gradually from acute pharyngitis to chronic one.

这个暑假很不幸我的喉咙由于某种原因变得嘶哑了，由急性咽炎变成慢性咽炎，久治不愈。

youdao

Have your symptoms gradually worsened over time, or did they come on suddenly?

CNN: Prostate gland enlargement

Gradually the conditions worsened.

ECONOMIST: Antarctic exploration