Why would a police officer by present in a patients hospital room?

There could be a variety of reason. The individual may have injured themselves in the process of committing a crime, or have been sent to the hospital after being assaulted. They could be a witness to a crime, and their hospital stay could be unrelated. Truly there are many, many reason for a police officer to make a personal visit to a hospital room.
Of course the police officer could just be visiting a friend or family~