This is the 4387th most frequent Chinese word.
慢性病
"慢性病" means "chronic disease."
慢性病 here is used to explain the necessity for ongoing treatment.
由于患有慢性病，他需要长期规律服药。
Due to having chronic diseases, he needs to take medication regularly for an extended period.
慢性病 is used to refer to general chronic diseases, emphasizing their prolonged effect.
慢性病对年轻人来说可能是一种长期的挑战。
Chronic diseases can be a long-term challenge for young people.
慢性病 in this sentence highlights the importance of prevention.