Most of the long-term harm from diabetes comes not from high blood glucose itself but from what it does to small and large blood vessels — and to the nerves they supply. The good news: every major complication is preventable, slowable, or treatable, especially when caught early. This guide covers the diabetes complications you should know about, how they’re screened for, and the most effective ways to reduce risk.
This is a general educational guide. Personal screening schedules and treatment depend on individual circumstances — your GP or diabetes team will tailor the plan to you.
Heart and circulation
People with diabetes have a 2–4 fold higher risk of cardiovascular disease than the general population. The mechanism is a combination of accelerated atherosclerosis (plaque build-up in arteries), endothelial dysfunction, raised inflammation, and clustering of risk factors (hypertension, dyslipidaemia, central obesity).
What’s monitored:
- Blood pressure — annually, more often if raised. NICE recommends a target of below 140/80 mmHg, or below 130/80 mmHg if there is kidney, eye, or cerebrovascular damage.
- Lipid profile — total cholesterol, LDL, HDL, triglycerides. Most people with type 2 diabetes are eligible for statin therapy for primary prevention.
- QRISK score (UK) or ASCVD risk (US) to estimate 10-year cardiovascular risk.
What reduces risk most: tight blood pressure control, statin therapy where indicated, smoking cessation, SGLT2 inhibitors and GLP-1 receptor agonists for those with established cardiovascular disease, and physical activity.
Kidneys (diabetic kidney disease)
Diabetes is the leading cause of chronic kidney disease (CKD) and dialysis worldwide. Damage progresses silently for years before symptoms appear, which is why annual screening matters.
What’s monitored:
- eGFR — an estimate of kidney filtration, calculated from blood creatinine. Below 60 ml/min/1.73m² indicates CKD; below 30 indicates severe CKD.
- Urinary albumin-to-creatinine ratio (uACR) — picks up early protein leak before eGFR falls. The most sensitive early marker of diabetic kidney disease.
- Both are checked at least annually under NICE NG28.
What slows progression most: blood pressure control (with an ACE inhibitor or ARB if there’s albuminuria), tight glycaemic control, SGLT2 inhibitors (now a cornerstone for diabetic CKD even without diabetes), GLP-1 receptor agonists, and the newer non-steroidal mineralocorticoid receptor antagonist finerenone.
Eyes (diabetic retinopathy and macular oedema)
Diabetic retinopathy remains a leading cause of vision loss in working-age adults. Background retinopathy is common after 10–20 years of diabetes; sight-threatening forms (proliferative retinopathy, macular oedema) are now far less common thanks to screening and earlier treatment.
What’s monitored: The NHS Diabetic Eye Screening Programme offers an annual digital retinal photograph from the age of 12 onwards for everyone with diabetes. Findings are graded R0–R3 and M0–M1, with referral pathways for anything beyond background.
What reduces risk most: good glycaemic and blood pressure control, attending screening, and prompt treatment of sight-threatening changes with anti-VEGF injections, laser photocoagulation, or vitrectomy when needed.
Feet (diabetic neuropathy and foot ulceration)
Peripheral neuropathy affects up to half of people with diabetes after 25 years. Loss of protective sensation, combined with reduced blood flow and altered foot mechanics, leads to ulcers — and ulcers are the leading reason behind non-traumatic amputations.
What’s monitored: annual foot review covering pulses, sensation (10 g monofilament, vibration), foot deformity, and skin integrity. Risk is stratified low / moderate / high / active problem under NICE NG19, with corresponding follow-up frequency.
Daily prevention: daily foot inspection (mirror or partner), well-fitting shoes, never walking barefoot, prompt attention to any cut, blister, or colour change. Any new foot ulcer in someone with diabetes is a clinical emergency — same-day specialist contact under NICE.
Other complications worth knowing about
- Gum and dental disease — diabetes accelerates periodontitis. Twice-daily brushing, flossing, and 6-monthly dental review are part of diabetes care.
- Sexual health and erectile dysfunction — common, often the first sign of vascular damage. Treatable; bring it up with your team rather than ignore it.
- Skin and wound healing — slower healing, higher infection risk. Take any wound that isn’t improving in 1–2 weeks seriously.
- Hearing loss — twice as common in diabetes; routine hearing checks are recommended.
- Cognitive change and dementia risk — modestly higher risk, particularly with recurrent severe hypoglycaemia.
- Mental health — depression and anxiety are 2–3 times more common; not strictly a “complication” but a major part of the picture.
The diabetes annual review checklist
Diabetes UK and NICE define a set of annual checks every adult with diabetes should have:
- HbA1c
- فشار خون
- BMI/weight
- Cholesterol/lipid profile
- Kidney check (eGFR + uACR)
- Foot examination
- Diabetic eye screening (digital retinal photo)
- Smoking-status review and cessation support
- Personal care plan review (goals, self-management, mood)
If you haven’t had all nine in the last 12 months, it’s worth asking your GP practice when you’re due. Audit data from the National Diabetes Audit show fewer than half of UK patients with type 2 diabetes get the full set every year — being the patient who asks makes a difference.
Read more on diabetes complications
- Understanding Kidney Disease in Diabetes: The Silent Threat
- The UACR Test: Your Best Defence Against Kidney Disease
- How High Blood Sugar Harms Your Kidneys
- Blood Pressure Targets for Kidney Health: How Low Should You Go?
- Finerenone (Kerendia): A New Non-Steroidal Option for Kidney Protection
- Dialysis and Diabetes: What to Expect When Kidneys Fail
- Contrast Dye and Diabetic Kidneys: What You Need to Know
- NSAIDs and Diabetes: Understanding the Kidney Risks
- CGM Patterns That Predict Cardiovascular Risk
- Plant-Based Eating for Heart Health with Diabetes
- Heart Rate Variability and Blood Sugar
- Tirzepatide and Cardiovascular Outcomes
Frequently asked questions
How long does it take to develop diabetes complications?
Most microvascular complications (eyes, kidneys, nerves) take 5–15 years to develop, though they can occur earlier in poorly controlled diabetes. Macrovascular complications (heart attack, stroke) often have already begun by the time type 2 diabetes is diagnosed, because insulin resistance precedes the diagnosis by years.
Can complications be reversed?
Some can be slowed or partially reversed — early kidney disease often improves with SGLT2 inhibitors and ACE/ARB therapy, retinopathy can stabilise with good glucose and blood pressure control, and neuropathy pain can ease over time. Established advanced damage (severe CKD, advanced retinopathy, deep ulcers) is harder to reverse but always worth trying to halt.
What HbA1c is “low enough” to prevent complications?
The biggest reductions in microvascular complication risk happen as HbA1c falls from very high values (e.g. 80+ mmol/mol) into the 50s. The benefit of pushing below 48 mmol/mol (6.5%) is smaller and must be balanced against hypoglycaemia risk. Most adults aim for 48–58 mmol/mol with their team.
Do all the complications come together, or one at a time?
They tend to cluster. Someone with diabetic retinopathy is much more likely to have kidney disease, neuropathy, and vascular disease than someone without. That’s why annual reviews check everything together — a positive find in one area triggers extra attention elsewhere.
Reviewed against NICE NG28, NICE NG17, NICE NG19, the ADA Standards of Care 2026, and the National Diabetes Audit. Last reviewed: May 2026.
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