Type 2 Diabetes Guide: Why HbA1c Targets Differ by Person, Choosing Medication in 2025, the Kidney Tests You Need Every Year, and Handling Hypoglycaemia

How common is diabetes, and why the kidney matters

The International Diabetes Federation estimated in 2025 that about 589 million adults (11.1%, one in nine) have diabetes, 4 in 10 undiagnosed, rising to 853 million by 2050 [1]. Over 90% is type 2.

About 30–40% of people with diabetes develop diabetic kidney disease (DKD), the leading cause of dialysis worldwide (in Taiwan, 45–50% of new dialysis starts are due to diabetes) [2][3]. The good news: the past decade brought drugs that protect kidney and heart together, and DKD progression can now be markedly slowed [2][3].

Diagnostic criteria

Any one of the following (repeat on another day if no classic symptoms) [2]:

HbA1c can be unreliable in anaemia, haemoglobin variants, CKD stage 4–5 and dialysis (altered red-cell lifespan, ESA therapy); use glucose monitoring or CGM instead [2][3].

HbA1c targets: why not 7% for everyone

ADA 2025 is built on individualisation [2]:

Why relax? ACCORD showed that very tight control (target <6.0%) in high-cardiovascular-risk patients increased mortality, largely through severe hypoglycaemia [4]. The immediate harm of hypoglycaemia to heart and brain outweighs a few months of slightly higher glucose.

Beyond HbA1c, CGM time in range >70% (70–180 mg/dL) and time below range <4% are increasingly important [2].

Medication in 2025: first ask "which organ needs protecting?"

ADA 2025 no longer insists on "metformin first". The first question is: is there cardiovascular disease, heart failure, CKD or obesity? [2]

Metformin remains cheap and effective, but do not start at eGFR <45 and stop at <30 (lactic acidosis); halve the dose at eGFR 30–45 [2][3].

SGLT2 inhibitor cautions: eGFR dips 3–5 mL/min after starting (a protective haemodynamic effect — don't stop); genital fungal infections are more common; pause during acute illness, fasting or for 3 days before surgery (ketoacidosis risk) [2][3].

Yearly checks: more than glucose

ADA and KDIGO recommend that everyone with type 2 diabetes have annually from diagnosis [2][3]:

1. eGFR (blood creatinine)
2. UACR (urine albumin-to-creatinine ratio, spot urine) — the most frequently omitted test, yet it detects kidney disease earlier than eGFR. UACR ≥30 mg/g is albuminuria.
3. Retinal examination
4. Foot examination (neuropathy, circulation, ulcers)
5. Lipids and blood pressure

If UACR ≥30 or eGFR <60, monitor 1–4 times a year and start an ACEi/ARB (even with normal BP) plus an SGLT2i [3]. This site's eGFR calculator and UACR reader help you interpret the report.

Hypoglycaemia: symptoms, treatment, prevention

Symptoms: cold sweat, trembling, palpitations, hunger, dizziness, blurred vision, slurred speech, confusion; seizures or coma if severe. People with long-standing diabetes or CKD may have no warning symptoms (hypoglycaemia unawareness) [2].

The 15–15 rule: glucose <70 mg/dL → take 15 g of fast-acting carbohydrate (3–4 glucose tablets, half a cup of juice, a tablespoon of sugar) → recheck after 15 minutes → repeat if still <70. Once recovered, if the next meal is >1 hour away, have a snack with protein and carbohydrate [2].

Kidney patients are especially prone: the kidney clears insulin and several glucose-lowering drugs (sulfonylureas, some DPP-4 inhibitors), so effects last longer as eGFR falls, and renal gluconeogenesis declines. At eGFR <30, glibenclamide (glyburide) is contraindicated and glimepiride/glipizide need dose reduction; insulin requirements often fall by 20–30% [3].

Severe hypoglycaemia (unconscious) requires glucagon (a nasal spray is available) from a bystander and an emergency call.

Notes for kidney patients and transplant recipients

• Dialysis: HbA1c is unreliable — CGM is preferred; glucose swings on dialysis days; many oral agents are contraindicated (metformin; limited SGLT2i evidence below eGFR 20); insulin and DPP-4 inhibitors (linagliptin needs no adjustment) are the main options [3].
• Post-transplant diabetes (PTDM): triggered by tacrolimus and steroids in about 10–30% of recipients; managed like type 2, but SGLT2i evidence in transplantation is thinner and urinary infection risk must be weighed; GLP-1 RAs may alter tacrolimus absorption (delayed gastric emptying), so monitor levels [3].
• Pause metformin around contrast studies (see this site's contrast article).

When to seek care

Urgently: glucose >300–400 mg/dL with nausea, vomiting, abdominal pain, deep rapid breathing, extreme thirst or altered consciousness (ketoacidosis or hyperosmolar state); hypoglycaemia with unconsciousness or seizure; a foot wound that turns black, smells, or has spreading redness.

Same day: glucose >250 for 2 consecutive days during infection or illness; recurrent hypoglycaemia <70 more than twice a week.

Questions to ask your doctor

1. What is my HbA1c target, and why?
2. Have I had a UACR test? When was the last one?
3. With my kidney function, can I take an SGLT2 inhibitor? Finerenone?
4. Which of my medicines need reducing or stopping as kidney function falls?
5. Do I need CGM? What should I do and keep at hand for hypoglycaemia?

References

1. International Diabetes Federation. IDF Diabetes Atlas, 11th edition. 2025. https://diabetesatlas.org/
2. American Diabetes Association. Standards of Care in Diabetes—2025. Diabetes Care. 2025;48(Suppl 1):S1–S352. https://doi.org/10.2337/dc25-SINT
3. KDIGO 2022 Clinical Practice Guideline for Diabetes Management in CKD. Kidney Int. 2022;102(5S):S1–S127. https://doi.org/10.1016/j.kint.2022.06.008
4. ACCORD Study Group. Effects of intensive glucose lowering in type 2 diabetes. N Engl J Med. 2008;358(24):2545–2559. https://doi.org/10.1056/NEJMoa0802743
5. Perkovic V, et al. CREDENCE. N Engl J Med. 2019;380(24):2295–2306. https://doi.org/10.1056/NEJMoa1811744
6. Perkovic V, et al. FLOW. N Engl J Med. 2024;391(2):109–121. https://doi.org/10.1056/NEJMoa2403347
7. Bakris GL, et al. FIDELIO-DKD. N Engl J Med. 2020;383(23):2219–2229. https://doi.org/10.1056/NEJMoa2025845

This article compiles publicly available medical information for educational purposes only. It is not medical advice and has not been reviewed by a practising physician. For any health or medication question, consult a qualified professional. For chest pain, sudden breathlessness, one-sided weakness or slurred speech, call your local emergency number or go to the emergency department immediately.