Final answer:
The 75-year-old man with type 2 diabetes and coronary artery disease who has recently started on insulin injections is at the highest risk for hyperosmolar hyperglycemic syndrome due to the combination of factors.
Step-by-step explanation:
The patient who is at the highest risk for hyperosmolar hyperglycemic syndrome is the 75-year-old man with type 2 diabetes and coronary artery disease who has recently started on insulin injections.
This patient is at higher risk due to the combination of advanced age, having type 2 diabetes, and starting on insulin injections.
Hyperosmolar hyperglycemic syndrome (HHS) is a serious condition that occurs when blood glucose levels become extremely high and cause severe dehydration.