Novolog vs. Fiasp Insulin in Non-critically Ill Hospitalized Patients With Type 2 Diabetes Mellitus

Inclusion criteria 1. English-speaking 2. Males and female adult subjects admitted to Boston Medical Center to a medical or surgical floor. 3. Consultation by the Inpatient Diabetes Service at Boston Medical Center is required prior to consent. 4. Age ≥ 21 and \<= 80 years. 5. Diagnosed with type 2 diabetes at least 180 days prior to screening. 6. Hyperglycemia during admission, as defined by a point of care and/or venous blood glucose ≥ 140 mg/dL. 7. Prior to admission subjects must be using one of the following for outpatient diabetes management: 1. Insulin 2. ≥ 2 oral/injectable agents 3. One oral/injectable agent with a hemoglobin A1c of ≥ 8% within 3 months of enrollment. 8. Patients who are expected to remain hospitalized for a minimum of 48 hours following CGM sensor placement. 9. BMI \<45 kg/m\^2. 10. Subjects must have insulin glargine dosing planned at bedtime for the duration of the study period. Morning and afternoon dosing of insulin glargine are exclusionary. Exclusion criteria: 1. Patients with a history of type 1 diabetes or late-onset autoimmune diabetes (LADA). 2. Treatment or plan for treatment with glucocorticoids during the index hospitalization. 3. Female patients who are pregnant (tested during hospitalization or screening) or breast-feeding during the hospitalization. 4. Patients admitted with the following conditions: diabetic ketoacidosis, hyperosmolar hyperglycemic state, solid organ transplantation, or coronary artery bypass surgery. 5. Prior diagnosis of gastroparesis or cirrhosis. 6. Acute or chronic kidney disease with a serum creatinine of ≥ 2 mg/dL at the time of screening. 7. Clinically significant nausea and/or vomiting or unable to consume more than 30 grams of carbohydrate at each meal. 8. Patients expected to receive nothing by mouth (NPO) for \>24 hours. 9. Use of continuous or intermittent enteral feeding or parenteral nutrition. 10. Patient receiving aspirin and/or vitamin C during the hospitalization. 11. Any mental condition rendering the subject unable to provide informed consent. 12. Patients currently incarcerated. 13. Patients using \>1 unit/kg/day of insulin prior to admission. 14. Insulin pump usage within the 2 weeks prior to or during admission. 15. Patients currently using real-time continuous glucose monitoring (CGM) or personal flash glucose monitoring system (FGM). 16. Patients with a history of an allergy to any of the types of insulin or one of the excipients in the insulin used in the study.