Final answer:
The default assumption for unspecified diabetes mellitus is Type 2 diabetes, not Type 1, because Type 2 is much more common.
Step-by-step explanation:
The statement "If the type of diabetes mellitus is not documented in the medical record, the default is Type 1 diabetes mellitus" is false. In medical coding and clinical practice, Type 2 diabetes mellitus is generally assumed when the type is not specified. This is because Type 2 diabetes is far more prevalent, representing about 90 percent of all cases of diabetes in the United States. Type 1 diabetes, known also as juvenile diabetes, is an autoimmune disease that leads to the destruction of insulin-producing beta cells in the pancreas and requires insulin injections for survival. Type 1 diabetes is usually diagnosed in children and young adults and represents a smaller portion of the diabetic population.