Type 2 Diabetes in Adults
Introduction
Type 2 diabetes is a chronic metabolic condition characterized by hyperglycemia arising from insulin resistance and progressive impairment of insulin secretion. Care should combine glycemic management with cardiovascular, kidney, eye, foot, and self-management support.[1]
Symptoms
Hyperglycemia may be asymptomatic. Possible features include polyuria, polydipsia, fatigue, blurred vision, recurrent infections, and unexplained weight loss. Vomiting, dehydration, altered mental status, or suspected metabolic decompensation requires urgent assessment.
Goals
For most adults, target A1C is 7.0% or lower. Consider 6.5% or lower in selected patients when achievable safely, and use a less stringent individualized range when hypoglycemia, frailty, comorbidity, or treatment burden outweighs benefit.[2]
Risk Factors
- Age, family history, history of gestational diabetes, polycystic ovary syndrome, and higher-risk ancestry.
- Overweight or central adiposity, physical inactivity, hypertension, dyslipidemia, cardiovascular disease, and sleep apnea.
- Medicines associated with dysglycemia and social barriers affecting food security, activity, and access to care.
Assessment
In an asymptomatic adult, confirm a laboratory result in the diabetes range on another day. Diagnostic thresholds include fasting plasma glucose at least 7.0 mmol/L, 2-hour plasma glucose at least 11.1 mmol/L after a 75 g oral glucose tolerance test, or A1C at least 6.5% when the assay and clinical setting are appropriate.[1]
- Assess symptoms, weight, blood pressure, medicines, hypoglycemia risk, cardiovascular disease, heart failure, kidney disease, pregnancy possibility, and self-management capacity.
- Review kidney function, albuminuria, lipids, feet, eyes, immunizations, and psychosocial health according to current care standards.
Non-Pharmacologics
- Use individualized nutrition therapy that is nutritionally adequate, culturally acceptable, and sustainable.
- Build aerobic activity, resistance training, and reduced sedentary time within ability and safety limits.
- Support sleep, tobacco cessation, weight goals, medication-taking routines, and recognition and treatment of hypoglycemia.
Pregnancy and breast feeding
Preconception, pregnancy, and breast feeding require pregnancy-specific glycemic targets, medication review, and coordinated interprofessional care. Refer promptly when pregnancy is planned or confirmed; do not assume the routine adult medication pathway applies.[4]
Monitoring
- Measure A1C about every 3 months when therapy is changing or targets are not met; monitor less often when treatment and results are stable.
- Match glucose monitoring to insulin or secretagogue use, hypoglycemia risk, symptoms, and the decisions the result will change.
- Monitor kidney function, albuminuria, cardiovascular risk, feet, eyes, adverse effects, adherence, and injection technique when applicable.
Tips
- Ask what matters most to the patient before intensifying therapy.
- Choose medicines using cardiorenal benefit, hypoglycemia risk, weight effect, kidney function, route, cost, coverage, and treatment burden.
- Provide a clear sick-day plan and revisit it when medicines or kidney function change.
Decision Making Logic
- Confirm diagnosis and assess whether urgent metabolic treatment is needed.
- Set an individualized A1C goal and identify cardiovascular disease, heart failure, and chronic kidney disease.
- Start lifestyle and self-management support.
- Select therapy for organ protection first when a compelling cardiorenal indication is present; otherwise choose based on A1C need and patient factors.
- Reassess response, tolerability, adherence, access, and hypoglycemia; add complementary therapy rather than allowing prolonged therapeutic inertia.
- Continue complication screening and risk-factor treatment even when A1C is at target.
Drug Tables
| Class | Potential role | Key considerations |
|---|---|---|
| Metformin | Common initial glucose-lowering therapy | Kidney function, gastrointestinal effects, vitamin B12 over long-term use |
| SGLT2 inhibitor | Cardiorenal benefit in selected CKD, heart failure, or cardiovascular-risk patients | Kidney function, volume status, genital infection risk, ketoacidosis precautions, sick-day plan |
| GLP-1 receptor agonist | Strong A1C lowering, weight effect, and cardiovascular benefit with selected agents | Gastrointestinal effects, injection/oral administration, gallbladder and pancreatitis history |
| DPP-4 inhibitor | Modest lowering with low hypoglycemia risk when used without insulin or a secretagogue | Kidney dose adjustment for most agents; avoid combining with a GLP-1 receptor agonist |
| Sulfonylurea | Effective, accessible glucose lowering | Hypoglycemia and weight gain; renal and meal-pattern considerations |
| Insulin | Highest glucose-lowering capacity; required in decompensation and selected clinical states | Hypoglycemia, education, monitoring, technique, titration, and treatment burden |
References
- Definition, Classification and Diagnosis of Diabetes, Prediabetes and Metabolic Syndrome — Diabetes Canada. Clinical Practice Guidelines
- Targets for Glycemic Control — Diabetes Canada. Clinical Practice Guidelines
- Pharmacologic Glycemic Management of Type 2 Diabetes in Adults: 2024 Update — Diabetes Canada. 2024 update
- Diabetes and Pregnancy — Diabetes Canada. Clinical Practice Guidelines
- Monitoring Glycemic Control — Diabetes Canada. Clinical Practice Guidelines
Professional reference only. Apply clinical judgment and verify patient-specific decisions against current authoritative guidance and product information.