2.1 Diabetes Mellitus: Diagnosis, Glycemic Targets & Pharmacotherapy

ABIM Internal Medicine Exam

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1 Chapter 0: The ABIM Exam, Blueprint & Study Strategy

0.1 Exam Format, Question Types & the 2026 Blueprint 0.2 Eligibility, Registration, Fees & Exam-Day Logistics 0.3 Scoring, the Passing Standard & Score Reports 0.4 Building a Blueprint-Weighted Study Plan

2 Chapter 1: Cardiovascular Disease (14% of Exam)

1.1 Ischemic Heart Disease & Acute Coronary Syndromes 1.2 Antithrombotic Therapy, Secondary Prevention & Mechanical Complications of MI 1.3 Atrial Fibrillation, Atrial Flutter & Stroke Prevention 1.4 Supraventricular Tachycardias, Ventricular Arrhythmias & Bradycardias 1.5 Heart Failure: Classification, Staging & Guideline-Directed Medical Therapy 1.6 Device Therapy, HFpEF & the Cardiomyopathies 1.7 Valvular Heart Disease & Endocarditis Prophylaxis 1.8 Pericardial Disease & Acute Aortic Syndromes 1.9 Hypertension: Classification, Diagnosis & Secondary Causes 1.10 Hypertensive Crises & Dyslipidemia 1.11 Adult Congenital Heart Disease & Coarctation of the Aorta 1.12 Syncope: Reflex, Orthostatic & Cardiac Causes 1.13 Cardiac Physical Examination, Murmurs & Antithrombotic Selection

3 Chapter 2: Endocrinology, Diabetes & Metabolism (9% of Exam)

2.1 Diabetes Mellitus: Diagnosis, Glycemic Targets & Pharmacotherapy 2.2 Insulin Therapy, Hyperglycemic Emergencies & Chronic Complications 2.3 Thyroid Function Testing & Hypothyroidism 2.4 Thyrotoxicosis, Thyroid Storm & Thyroid Nodules 2.5 Adrenal & Pituitary Disorders 2.6 Hypercalcemia, Hypocalcemia & Disorders of Mineral Metabolism 2.7 Osteoporosis & Paget Disease of Bone 2.8 Ovarian, Testicular & Reproductive Endocrine Disorders 2.9 Hypoglycemia, Endocrine Tumors, Polyglandular Syndromes & Severe Hypertriglyceridemia

4 Chapter 3: Gastroenterology & Hepatology (9% of Exam)

3.1 Esophageal Disease 3.2 Stomach & Duodenal Disease and Gastrointestinal Hemorrhage 3.3 Inflammatory Bowel Disease 3.4 Celiac Disease & Irritable Bowel Syndrome 3.5 Diverticular Disease & Colorectal Cancer Screening 3.6 Viral Hepatitis, Steatotic & Alcohol-Associated Liver Disease 3.7 Cirrhosis & the Complications of Portal Hypertension 3.8 Acute Pancreatitis 3.9 Chronic Pancreatitis & Biliary Tract Disease 3.10 Inherited, Autoimmune & Drug-Induced Liver Disease 3.11 Small Intestinal Disease, Ischemia & Gastrointestinal Complications of HIV

5 Chapter 4: Infectious Disease (9% of Exam)

4.1 Lower Respiratory Tract Infections & Sepsis Syndromes 4.2 Viral Respiratory Pathogens & Tuberculosis 4.3 Central Nervous System Infections 4.4 Skin, Soft Tissue, Bone & Joint Infections 4.5 Infective Endocarditis & Cardiovascular Infection 4.6 Clostridioides difficile & Catheter-Related Bloodstream Infection 4.7 HIV Diagnosis, Antiretroviral Therapy & Prevention 4.8 Opportunistic Infections & Sexually Transmitted Infections 4.9 Fever of Unknown Origin, Neutropenic Fever & Toxic Shock 4.10 Travel-Related Illness, Vector-Borne Disease & Outbreaks 4.11 Infection Prevention, Nosocomial Infection & Postexposure Prophylaxis 4.12 Rheumatic Fever, Poststreptococcal Disease, Enteric & Hepatic Infections

6 Chapter 5: Pulmonary Disease (9% of Exam)

5.1 COPD: Diagnosis, GOLD Classification & Initial Pharmacotherapy 5.2 Interventions That Reduce COPD Mortality & Exacerbation Management 5.3 Asthma: Diagnosis, Stepwise Therapy & Status Asthmaticus 5.4 Interstitial Lung Disease & Idiopathic Pulmonary Fibrosis 5.5 Sarcoidosis, Hypersensitivity Pneumonitis & Occupational Lung Disease 5.6 Pulmonary Embolism: Diagnosis, Risk Stratification & Anticoagulation 5.7 Pulmonary Hypertension & Sleep-Disordered Breathing 5.8 Acute Respiratory Distress Syndrome & Mechanical Ventilation 5.9 Pleural Disease, Empyema & Pneumothorax 5.10 Bronchiectasis, Cystic Fibrosis & Restrictive Lung Disease 5.11 Evaluation of Cough, Dyspnea, Hemoptysis & the Solitary Pulmonary Nodule

7 Chapter 6: Rheumatology & Orthopedics (9% of Exam)

6.1 Rheumatoid Arthritis: Diagnosis & Systemic Manifestations 6.2 Antirheumatic Pharmacotherapy & the Spondyloarthropathies 6.3 Gout: Pathophysiology & Acute Management 6.4 Urate-Lowering Therapy & Calcium Pyrophosphate Deposition Disease 6.5 Osteoarthritis 6.6 Systemic Lupus Erythematosus 6.7 Systemic Sclerosis, Sjogren Syndrome & Inflammatory Myopathies 6.8 The Vasculitides 6.9 Regional Musculoskeletal Syndromes, Back Pain & Sports Injuries 6.10 Other Primary Rheumatic Disorders & Mixed Connective Tissue Disease 6.11 Osteonecrosis & Metabolic Bone Disease

8 Chapter 7: Hematology (6% of Exam)

7.1 Approach to Anemia & the Microcytic Anemias 7.2 Macrocytic, Normocytic & Hemolytic Anemias 7.3 Hemoglobinopathies, Thalassemias & Paroxysmal Nocturnal Hemoglobinuria 7.4 Platelet Disorders, Thrombocytopenia & the Bleeding Patient 7.5 Coagulation Factor Disorders, Thrombophilia & Anticoagulant Reversal 7.6 Acute Leukemias, Chronic Leukemias & Myeloproliferative Neoplasms 7.7 Lymphomas & Plasma Cell Disorders 7.8 Myelodysplastic Syndrome, Myeloproliferative Neoplasms & Porphyria 7.9 Transfusion Medicine & Late Complications of Transplantation

9 Chapter 8: Medical Oncology (6% of Exam)

8.1 Breast, Lung, Colorectal & Prostate Cancer 8.2 Oncologic Emergencies 8.3 Genitourinary & Gynecologic Malignancies 8.4 Head and Neck, Bone & Soft Tissue Cancer and Cancer of Unknown Primary 8.5 Complications of Cancer & Its Treatment 8.6 Cancer Prevention, Survivorship & Psychosocial Care

10 Chapter 9: Nephrology & Urology (6% of Exam)

9.1 Acute Kidney Injury: Staging, Etiology & Urine Microscopy 9.2 Glomerular Disorders & Nephrotic Syndrome 9.3 Nephritic Syndromes, RPGN & Indications for Renal Replacement Therapy 9.4 Chronic Kidney Disease: Staging & Progression Retardation 9.5 Complications of Chronic Kidney Disease: Anemia, CKD-MBD & Acidosis 9.6 Hyponatremia, Hypernatremia & Water Balance 9.7 Potassium Disorders & Systematic Acid-Base Analysis 9.8 Renal Tubular Acidosis & Nephrolithiasis 9.9 Prostate Disorders, Urinary Incontinence & Other Urologic Conditions 9.10 Cystic Kidney Disease, Obstructive Uropathy, Tubulointerstitial Disease & Hematuria

11 Chapter 10: Neurology (4% of Exam)

10.1 Acute Ischemic Stroke: Syndromes & Reperfusion 10.2 Transient Ischemic Attack, Secondary Prevention & Hemorrhagic Stroke 10.3 Headache & Facial Pain 10.4 Seizures, Epilepsy & Movement Disorders 10.5 Multiple Sclerosis & Neuromuscular Junction Disorders 10.6 Motor Neuron Disease & Acute Peripheral Neuropathy 10.7 Cranial Neuropathies & Neuro-Ophthalmology 10.8 Peripheral Neuropathies, CNS Tumors & Other Neurologic Disorders

12 Chapter 11: Psychiatry & Behavioral Health (4% of Exam)

11.1 Major Depressive Disorder & Medical Mimics 11.2 Antidepressant Pharmacotherapy & Treatment-Resistant Depression 11.3 Bipolar Disorder, Mood Stabilizers & Lithium Toxicity 11.4 Anxiety, Stress-Related & Obsessive-Compulsive Disorders 11.5 Alcohol Use Disorder & Withdrawal 11.6 Pharmacotherapy for Alcohol & Opioid Use Disorder 11.7 Toxidromes, Psychiatric Emergencies & Suicide Risk Assessment 11.8 Psychotic, Somatic Symptom, Factitious & Personality Disorders 11.9 Eating Disorders, Sleep Disorders & Sexual Health

13 Chapter 12: Dermatology (3% of Exam)

12.1 Dermatitis, Papulosquamous & Inflammatory Dermatoses 12.2 Acne, Rosacea & Cutaneous Infections 12.3 Herpes Zoster & Autoimmune Blistering Diseases 12.4 Nodules, Tumors & Cutaneous Oncology 12.5 Dermatologic Emergencies & Severe Cutaneous Adverse Reactions 12.6 Pigment Disorders, Alopecia, Nail Disease & Photosensitivity 12.7 Vascular Dermatoses, Environmental Injury & Cutaneous Signs of Systemic Disease

14 Chapter 13: Obstetrics & Gynecology / Women's Health (3% of Exam)

13.1 Contraception, Preconception Care & Teratogenicity 13.2 Hypertensive Disorders of Pregnancy & Gestational Diabetes 13.3 Thyroid Disease & Venous Thromboembolism in Pregnancy 13.4 Menopause & Menopausal Hormone Therapy 13.5 Abnormal Uterine Bleeding, Endometrial Disease & Gynecologic Cancer Screening 13.6 Breast Disorders & Diseases of the Vulva and Vagina 13.7 Menstrual Disorders, Fibroids, Endometriosis & Early Pregnancy Complications

15 Chapter 14: Geriatric Syndromes (3% of Exam)

14.1 Comprehensive Geriatric Assessment & Frailty 14.2 Falls, Gait Assessment & Polypharmacy 14.3 Urinary Incontinence & Pressure Injuries in Older Adults 14.4 Mild Cognitive Impairment, Dementia & Its Subtypes 14.5 Delirium & the Pharmacotherapy of Cognitive Disorders 14.6 Palliative Care, Hospice & Advance Care Planning 14.7 Chronic Wounds, Nutrition, Swallowing, Constipation & Hip Fracture 14.8 Sensory Impairment, Dizziness, Elder Mistreatment & Care Settings

16 Chapter 15: Allergy & Immunology (2% of Exam)

15.1 Anaphylaxis: Recognition & Emergency Management 15.2 Urticaria & Angioedema 15.3 Drug Allergy, Desensitization & Adult Immunodeficiency 15.4 Food Allergy, Insect Venom Hypersensitivity, Serum Sickness & Contrast Reactions 15.5 Rhinitis, Conjunctivitis, Eosinophilic & Mast Cell Disorders

17 Chapter 16: Preventive Medicine, Immunization & Clinical Epidemiology

16.1 The USPSTF Framework & Evidence-Based Cancer Screening 16.2 Cardiovascular & Metabolic Screening and Primary Prevention 16.3 Adult Immunization & Vaccines in Special Populations 16.4 Clinical Epidemiology, Biostatistics & Study Design

18 Chapter 17: Miscellaneous - Ethics, Patient Safety & Quality Improvement (2% of Exam)

17.1 Principles of Bioethics & Decisional Capacity 17.2 Informed Consent, Treatment Refusal & Special Scenarios 17.3 Surrogate Decision-Making, Advance Directives & Confidentiality 17.4 Patient Safety Science, Medical Error & Diagnostic Reasoning 17.5 Quality Improvement Methods, Health Disparities & Health Equity

19 Chapter 18: Perioperative Medicine & Medical Consultation

18.1 Preoperative Cardiovascular Risk Assessment 18.2 Preoperative Pulmonary Risk & Perioperative Medication Management 18.3 Perioperative Anticoagulation, Bridging & Postoperative Complications

20 Chapter 19: Ophthalmology (1% of Exam)

19.1 The Acute Red Eye & Ophthalmic Emergencies 19.2 Painless Vision Loss & Chronic Ophthalmic Disease 19.3 Uveitis, Scleritis & Orbital Disease

21 Chapter 20: Otolaryngology & Dental Medicine (1% of Exam)

20.1 Dizziness, Vertigo & Epistaxis 20.2 Ear Disorders, Hearing Loss & Upper Respiratory Infections 20.3 Oral Cavity, Salivary Gland, Laryngeal & Taste and Smell Disorders

2.1 Diabetes Mellitus: Diagnosis, Glycemic Targets & Pharmacotherapy

Key Takeaways Explain This Topic AI

The diabetes mellitus blueprint subsection enumerates type 1, type 2, diabetes in pregnancy, and complications of diabetes.

Diagnosis requires a hemoglobin A1c of 6.5% or higher, fasting glucose of 126 mg/dL or higher, a two-hour value of 200 mg/dL or higher, or a random glucose of 200 mg/dL or higher with classic symptoms.

Metformin remains first line for glycemic control, but agent selection is dominated by comorbidity rather than by A1c-lowering potency.

SGLT2 inhibitors are indicated for albuminuric chronic kidney disease and heart failure independent of the A1c value.

Hemoglobin A1c is unreliable in hemoglobinopathies, recent transfusion, hemolysis, iron deficiency and advanced kidney disease, where fructosamine or glucose monitoring is used instead.

Last updated: August 2026

Diabetes mellitus represents a group of metabolic disorders characterized by persistent hyperglycemia resulting from defects in insulin secretion, insulin action, or both. For the ABIM certification examination, mastery of diagnostic thresholds, individualized glycemic targets, organ-protective pharmacotherapy selection, emergent DKA/HHS management protocols, and chronic complication surveillance is essential.

• 1. Diagnostic Criteria & Screening Guidelines
• Formal Diagnostic Criteria

According to the American Diabetes Association (ADA) Standards of Care, diagnosis requires one of the following criteria. In the absence of unequivocal symptomatic hyperglycemia (polyuria, polydipsia, polyphagia, unintentional weight loss), a diagnosis requires two abnormal test results from the same sample or two separate test samples:

Test Normal Prediabetes Diabetes Mellitus

Fasting Plasma Glucose (FPG) < 100 mg/dL (5.6 mmol/L) 100–125 mg/dL (5.6–6.9 mmol/L) (IFG) >= 126 mg/dL (7.0 mmol/L) (fasting >=8 hr)

• 2-Hour 75g OGTT < 140 mg/dL (7.8 mmol/L) 140–199 mg/dL (7.8–11.0 mmol/L) (IGT) >= 200 mg/dL (11.1 mmol/L)
• Hemoglobin A1c (HbA1c) < 5.7% (39 mmol/mol) 5.7%–6.4% (39–47 mmol/mol) >= 6.5% (48 mmol/mol) (NGSP-certified)
• Random Plasma Glucose — — >= 200 mg/dL (11.1 mmol/L) + classic symptoms

Board Exam Pearl (HbA1c Discrepancies): Conditions that alter erythrocyte turnover invalidate HbA1c. Hemoglobinopathies (sickle cell trait/disease), hemolytic anemia, recent blood transfusion, severe blood loss, and hemodialysis falsely lower HbA1c. Severe iron deficiency anemia and asplenia falsely elevate HbA1c. In these clinical scenarios, rely on fasting/prandial plasma glucose measurements, continuous glucose monitoring (CGM), or serum fructosamine / glycated albumin (reflects 2–3 week glycemic control).

Screening Recommendations

General Population: Screen all asymptomatic adults starting at age 35 (USPSTF/ADA), repeating every 3 years if normal.

Overweight/Obese Adults (BMI >=25 kg/m2, or >=23 kg/m2 in Asian Americans): Screen at any age if >=1 additional risk factor is present: first-degree relative with diabetes, high-risk ethnicity (Black, Hispanic, American Indian, Asian American), history of cardiovascular disease, hypertension (>=130/80 mmHg or on therapy), HDL-C <35 mg/dL and/or triglycerides >250 mg/dL, polycystic ovary syndrome (PCOS), physical inactivity, or history of gestational diabetes mellitus (GDM; rescreen lifelong every 3 years).

Prediabetes Management: Intensive lifestyle intervention (7% weight loss, >=150 min/week moderate-intensity physical activity) reduces diabetes incidence by 58%. Metformin is specifically indicated for prediabetes in those aged 25–59 years with BMI >=35 kg/m2, higher fasting glucose (>=110 mg/dL), higher HbA1c (>=6.0%), or women with prior GDM.

2. ADA Glycemic Targets & CGM Metrics

Glycemic targets must be strictly individualized based on duration of diabetes, age/life expectancy, comorbid conditions, established vascular complications, hypoglycemia risk/awareness, and patient resources.

Standard vs. Individualized Glycemic Goals

• Clinical Context HbA1c Target Preprandial Capillary Glucose Peak Postprandial Capillary Glucose (1–2 hr)
• General Nonpregnant Adult < 7.0% (53 mmol/mol) 80–130 mg/dL (4.4–7.2 mmol/L) < 180 mg/dL (10.0 mmol/L)

Stringent Goal (Young, newly diagnosed, long life expectancy, no ASCVD, no hypoglycemia risk) < 6.5% (48 mmol/mol) 70–110 mg/dL < 140 mg/dL

Less Stringent Goal (History of severe hypoglycemia, hypoglycemia unawareness, limited life expectancy, advanced micro/macrovascular complications, extensive comorbidities) < 8.0% (64 mmol/mol) 100–150 mg/dL < 200 mg/dL

Frail Elderly / End-of-Life Avoid hypoglycemia & symptomatic hyperglycemia (A1c target not primary focus; up to <8.5%) 100–180 mg/dL < 250 mg/dL

Continuous Glucose Monitoring (CGM) Ambulatory Glucose Profile (AGP) Targets

For most non-pregnant adults using CGM, standard international consensus targets include:

Time in Range (TIR: 70–180 mg/dL [3.9–10.0 mmol/L]): > 70% (every 10% increase in TIR correlates with ~0.8% reduction in HbA1c and reduced microvascular risk).

Time Below Range (TBR Level 1: 54–69 mg/dL): < 4% (~1 hour/day).

Time Below Range (TBR Level 2: < 54 mg/dL): < 1% (~15 minutes/day).

Time Above Range (TAR Level 1: 181–250 mg/dL): < 25%.

Time Above Range (TAR Level 2: > 250 mg/dL): < 5%.

Glycemic Variability (%CV): Target <= 36%.

Loading diagram... ADA 2026 Pharmacotherapy Decision Framework for Type 2 Diabetes

3. Antihyperglycemic Pharmacotherapy

Class-by-Class Comparative Analysis +---------------------------------------------------------------------------------------------------------+

• | CLASS / AGENTS | PRIMARY MECHANISM | CLINICAL BENEFITS | RISKS / ADVERSE EFFECTS |
• +----------------------+----------------------------+--------------------------+---------------------------+
• | Biguanides | Inhibits hepatic | Weight neutral; no | GI distress (diarrhea); |
• | - Metformin | gluconeogenesis via AMPK; | hypoglycemia monotherapy;| Vitamin B12 deficiency; |
• | | improves peripheral insulin| modest CV mortality | Lactic acidosis risk |
• | | sensitivity | benefit | (avoid if eGFR < 30) |
• +----------------------+----------------------------+--------------------------+---------------------------+
• | SGLT2 Inhibitors | Inhibits SGLT2 in renal | Major reduction in HF | Mycotic genital infections|
• | - Empagliflozin | proximal tubule -> enhances| hospitalizations, CKD | Volume depletion / AKI; |
• | - Dapagliflozin | urinary glucose excretion | progression, and CV death| Euglycemic DKA (euDKA); |
• | - Canagliflozin | & osmotic diuresis | (independent of baseline | Fournier gangrene |
• | | | HbA1c); weight loss | |
• +----------------------+----------------------------+--------------------------+---------------------------+
• | GLP-1 Receptor | Activates GLP-1 receptor ->| Significant ASCVD event | Nausea, vomiting, diarrhea|
• | Agonists | glucose-dependent insulin, | reduction (MACE), | Pancreatitis risk; |
• | - Semaglutide (SQ/PO)| suppresses glucagon, | substantial weight loss | Medullary thyroid cancer |
• | - Dulaglutide | slows gastric emptying, | (Semaglutide 15%), slows | & MEN 2 contraindication; |
• | - Liraglutide | enhances satiety | CKD progression | Worsening retinopathy |
• +----------------------+----------------------------+--------------------------+---------------------------+
• | Dual GIP/GLP-1 RA | Co-agonism of GIP and | Exceptional HbA1c | GI disturbances (nausea, |
• | - Tirzepatide | GLP-1 receptors -> | lowering (>2.0-2.5%) and | constipation, diarrhea); |
• | | synergistic insulinotropism| profound weight loss | MTC / MEN 2 contra- |
• | | and energy regulation | (>20% in SURMOUNT/SURPASS| indication |
• +----------------------+----------------------------+--------------------------+---------------------------+
• | DPP-4 Inhibitors | Inhibits DPP-4 enzyme, | Weight neutral; low | Nasopharyngitis; joint |
• | - Sitagliptin | prolonging endogenous GLP-1| hypoglycemia risk; | pain; Saxagliptin |
• | - Linagliptin | and GIP activity | well-tolerated | increases HF risk; |
• | - Saxagliptin | | (Linagliptin: no renal | Do not combine with |
• | | | adjustment needed) | GLP-1 RAs |
• +----------------------+----------------------------+--------------------------+---------------------------+
• | Thiazolidinediones | PPAR-gamma agonist -> | Durable glycemic control;| Fluid retention / edema; |
• | - Pioglitazone | increases insulin | reduces recurrent stroke | Heart Failure exacer- |
• | | sensitivity in muscle, fat,| risk (IRIS trial); | bation (Contraindicated in|
• | | and liver | improves MASH/NASH | NYHA Class III/IV HF); |
• | | | histology | Bone fractures; weight gain
• +----------------------+----------------------------+--------------------------+---------------------------+
• | Sulfonylureas | Closes ATP-sensitive K+ | Rapid glucose lowering; | Hypoglycemia; weight gain;|
• | - Glimepiride | channels on beta cells -> | low cost | Avoid Glyburide in renal |
• | - Glipizide | stimulates insulin release | | impairment (active |
• | - Glyburide | | | metabolite accumulation) |
• +----------------------+----------------------------+--------------------------+---------------------------+
• Renal Dosing Thresholds & Critical Safety Rules

Metformin: Obtain baseline eGFR prior to initiation. eGFR >=45 mL/min: Full dose (up to 2000–2550 mg/day). eGFR 30–44 mL/min: Max dose 1000 mg/day; do not start de novo. eGFR <30 mL/min: Contraindicated . Hold prior to iodinated contrast procedures in patients with eGFR <60 or hepatic dysfunction; restart after 48 hours if renal function remains stable.

SGLT2 Inhibitors: Glycemic efficacy declines at eGFR <45 mL/min, but organ-protective cardiorenal benefits persist down to eGFR 20 mL/min . Hold SGLT2 inhibitors >=3–4 days prior to major elective surgery or extreme endurance athletics to prevent euglycemic DKA (caused by glycosuria masking severe insulinopenia while glucagon/ketogenesis surge).

Sulfonylureas: Glipizide is metabolized by the liver to inactive metabolites and is the preferred sulfonylurea in CKD. Glyburide produces active renally cleared metabolites and is contraindicated in renal insufficiency due to severe prolonged hypoglycemia.