NICE 2026 Diabetes Guidelines: Screening, Diagnosis, and Management
Screening Recommendations
All adults should begin diabetes screening at age 35 years using fasting plasma glucose, HbA1c, or 2-hour oral glucose tolerance test. 1, 2, 3
Earlier Screening Criteria
- Screen adults younger than 35 years when BMI ≥25 kg/m² (≥23 kg/m² for Asian Americans) PLUS any additional risk factor: 1, 2, 3
- First-degree relative with diabetes 1, 2
- High-risk ethnicity (African American, Latino, Native American, Asian American, Pacific Islander) 1, 2
- History of cardiovascular disease 1, 2
- Hypertension (≥130/80 mmHg or on therapy) 1, 2
- HDL cholesterol <35 mg/dL or triglycerides >250 mg/dL 1, 2
- Polycystic ovary syndrome 1, 2
- Physical inactivity 1, 2
- Insulin resistance conditions (severe obesity, acanthosis nigricans) 1, 2
- Medications: glucocorticoids, statins, thiazide diuretics, certain HIV medications, second-generation antipsychotics 1
Pediatric Screening
- Screen children/adolescents after puberty onset or age 10 years (whichever is earlier) when overweight (BMI ≥85th percentile) or obese (BMI ≥95th percentile) PLUS at least one risk factor: 1, 2
Screening Intervals
- Repeat screening every 3 years when initial results are normal 1, 2, 3
- Screen annually when prediabetes is identified (HbA1c 5.7-6.4%, fasting glucose 100-125 mg/dL, or 2-hour OGTT 140-199 mg/dL) 1, 2
- Screen at least every 3 years for women with prior gestational diabetes 1
Diagnostic Criteria
Diabetes is diagnosed when ANY of the following criteria are met (confirmation on a separate day required unless classic symptoms present): 1, 2, 3
| Test | Diagnostic Threshold | Prediabetes Range |
|---|---|---|
| HbA1c | ≥6.5% (48 mmol/mol) | 5.7-6.4% (39-47 mmol/mol) |
| Fasting plasma glucose | ≥126 mg/dL (7.0 mmol/L) after ≥8-hour fast | 100-125 mg/dL (5.6-6.9 mmol/L) |
| 2-hour OGTT (75-g glucose load) | ≥200 mg/dL (11.1 mmol/L) | 140-199 mg/dL (7.8-11.0 mmol/L) |
| Random plasma glucose | ≥200 mg/dL (11.1 mmol/L) PLUS classic symptoms* | N/A |
*Classic symptoms: polyuria, polydipsia, unexplained weight loss 1
Critical Testing Requirements
- Consume at least 150 g carbohydrate daily for 3 days before OGTT 1, 3
- Use only NGSP-certified laboratory methods for HbA1c; point-of-care assays are NOT acceptable for diagnosis 1, 2
- Confirm abnormal results with repeat testing on a separate day unless unequivocal hyperglycemia with symptoms 1, 2
HbA1c Testing Limitations
Do NOT use HbA1c for diagnosis in: 1, 4
- Hemoglobinopathies (sickle cell disease, thalassemia) 1
- Conditions affecting red cell turnover (recent blood loss, transfusion, hemolytic anemia, pregnancy) 1, 4
- Hemodialysis or erythropoietin therapy 4
- HIV infection (may underestimate glycemia) 1
Type 2 Diabetes: First-Line Treatment
Immediate Pharmacologic Initiation
Start metformin at diagnosis for all patients without contraindications, regardless of baseline HbA1c. 2, 3
- Verify adequate renal function before starting: serum creatinine <1.5 mg/dL (men) or <1.4 mg/dL (women) 2
- Titrate metformin up to 2000 mg daily as tolerated 3
- Measure serum creatinine at least annually and when increasing dose 2
- Avoid metformin in unstable or hospitalized heart failure; may use in stable heart failure with normal renal function 2
HbA1c-Driven Treatment Algorithm
| Baseline HbA1c | Action | Target HbA1c |
|---|---|---|
| <7.5% | Metformin monotherapy | 6.5% (48 mmol/mol) if on lifestyle ± metformin alone [2,3] |
| 7.5-8.9% | After 3 months on optimized metformin, add second agent | 7.0% (53 mmol/mol) if on hypoglycemia-risk agents [2,3] |
| ≥9.0% | Initiate dual therapy immediately (metformin + second agent) [3] | 7.0% (53 mmol/mol) [2,3] |
| ≥10-12% or symptomatic hyperglycemia | Consider starting insulin from outset [3] | 7.0% (53 mmol/mol) [2,3] |
Comorbidity-Driven Second-Line Agent Selection
The choice of second agent depends on specific comorbidities: 3
- Heart failure (reduced or preserved ejection fraction): SGLT2 inhibitors reduce heart failure hospitalizations 3
- Chronic kidney disease (eGFR 20-60 mL/min/1.73 m² and/or albuminuria): SGLT2 inhibitors slow CKD progression and reduce cardiovascular events 3
- eGFR <30 mL/min/1.73 m²: GLP-1 receptor agonists (lower hypoglycemia risk, cardiovascular benefit) 3
- Established cardiovascular disease or high CV risk: GLP-1 receptor agonists or SGLT2 inhibitors reduce atherosclerotic cardiovascular disease by 12-26%, heart failure by 18-25%, and kidney disease progression by 24-39% 3
Note: SGLT2 inhibitor glycemic efficacy wanes when eGFR falls below 45 mL/min/1.73 m². 3
Type 2 Diabetes: Treatment Intensification
When to Intensify
If HbA1c rises to ≥7.5% (58 mmol/mol) on metformin monotherapy after 3 months, add a second agent and reinforce lifestyle adherence. 2, 3
Preferred Intensification Strategy
GLP-1 receptor agonists (including dual GIP/GLP-1 agents) are favored over insulin for most patients requiring intensification. 3
- Produce >5% weight loss in most individuals 3
- Lower cardiovascular and kidney disease risk 3
- Reduce hypoglycemia risk compared to insulin 3
When Insulin Is Necessary
If insulin is required, combine it with a GLP-1 receptor agonist to achieve superior glycemic control, promote weight loss, and reduce hypoglycemia. 3
- Continue other glucose-lowering agents (except when contraindicated) 3
- Reassess sulfonylureas or meglitinides to minimize hypoglycemia 3
- Monitor for insulin over-basalization: basal insulin dose >0.5 U/kg/day, marked bedtime-to-morning glucose differential, frequent hypoglycemia, or high glycemic variability 3
Agents to Avoid
- Avoid sulfonylureas in older adults due to prolonged half-life and heightened hypoglycemia risk 2
- Avoid thiazolidinediones in symptomatic heart failure 2
Individualized HbA1c Targets
HbA1c targets should be individualized based on treatment regimen, hypoglycemia risk, and patient characteristics: 2, 3
| Clinical Scenario | Target HbA1c | Rationale |
|---|---|---|
| Lifestyle ± metformin alone | 6.5% (48 mmol/mol) | No hypoglycemia risk [2,3] |
| Any hypoglycemia-risk agent (sulfonylureas, insulin) | 7.0% (53 mmol/mol) | Balance benefit vs. hypoglycemia [2,3] |
| Older/frail adults with limited life expectancy | >7.0% (relaxed) | Unlikely to realize long-term benefit [2] |
| High hypoglycemia-related harm risk (fall risk, impaired awareness, professional drivers) | >7.0% (relaxed) | Enhance safety [2] |
| Significant comorbidities | >7.0% (relaxed) | Patient-centered balance of benefits/harms [2] |
Critical caveat: Striving for HbA1c <7% can increase risk of death, weight gain, and hypoglycemia in many patients; individualize targets accordingly. 2
Type 1 Diabetes: Screening and Diagnosis
Screening for Type 1 Diabetes Risk
Screening for type 1 diabetes risk is NOT recommended for the general population outside research studies. 1
- Consider islet autoantibody testing in first-degree relatives of individuals with type 1 diabetes within a research study (e.g., TrialNet) 1
- Presence of ≥2 islet autoantibodies predicts 70% progression to type 1 diabetes within 10 years and 84% within 15 years 1
- Individuals testing positive should receive counseling about diabetes risk, symptoms, and DKA prevention 1
Diagnosis of Type 1 Diabetes
In patients with classic symptoms (polyuria, polydipsia, weight loss) and markedly elevated glucose, measurement of plasma glucose confirms diagnosis. 1
- Random plasma glucose ≥200 mg/dL (11.1 mmol/L) plus symptoms is diagnostic 1
- Approximately 25-50% of type 1 diabetes patients present with life-threatening DKA at diagnosis 1
- In adults without traditional risk factors or of younger age, consider islet autoantibody testing (e.g., GAD65) to exclude type 1 diabetes 1
Idiopathic Type 1 Diabetes
A minority of type 1 diabetes patients have no evidence of autoimmunity (autoantibody-negative), particularly those of African or Asian ancestry. 1
- These individuals may have episodic DKA with varying insulin deficiency between episodes 1
- Insulin requirement may be intermittent 1
Monitoring and Complication Screening
Glycemic Monitoring
Re-check HbA1c after 3 months; if target not reached, add a second agent. 2
Nephropathy Screening
- Begin annual urine albumin-to-creatinine ratio (uACR) testing 5 years after type 1 diabetes diagnosis or at type 2 diabetes diagnosis 1
- Use first morning void urine sample; if unavailable, collect at same time of day when well-hydrated and fasting ≥2 hours 1
- If eGFR <60 mL/min/1.73 m² and/or albuminuria >30 mg/g creatinine, repeat uACR every 6 months 1
- Optimize glycemic and blood pressure control to reduce nephropathy risk 2
Retinopathy Screening
- Type 1 diabetes: initial dilated eye exam within 5 years after diagnosis 2
- Type 2 diabetes: initial dilated eye exam shortly after diagnosis 2
- Subsequent exams annually (or every 2-3 years after consecutive normal exams); more frequently if retinopathy progressing 2
- Women with pre-existing diabetes planning pregnancy or who become pregnant: comprehensive eye exam in first trimester with close follow-up throughout pregnancy and 1 year postpartum 2
- Promptly refer macular edema, severe non-proliferative diabetic retinopathy, or proliferative diabetic retinopathy to an ophthalmologist 2
Foot Care
- Perform annual comprehensive foot examination: visual inspection, foot pulses, loss of protective sensation (10-g monofilament plus vibration, pinprick, ankle reflex, or vibration perception threshold) 2
- Provide foot self-care education to all patients 2
- Use multidisciplinary approach for foot ulcers or high-risk feet (prior ulcer/amputation) 2
Cardiovascular Risk Management
Blood Pressure Targets
Measure blood pressure at every routine diabetes visit. 2
Target systolic <130 mmHg and diastolic <80 mmHg. 2
- BP 130-139/80-89 mmHg: Initiate lifestyle therapy (weight loss, DASH diet, sodium <2,300 mg/day, potassium increase, alcohol moderation, physical activity) for up to 3 months; add pharmacologic agents if targets unmet 2
- BP ≥140/90 mmHg: Start pharmacologic therapy immediately plus lifestyle measures 2
- Consider ACE-inhibitor therapy in patients with established cardiovascular disease 2
Lipid Management
Obtain fasting lipid profile at least annually (or every 2 years if low-risk: LDL <100 mg/dL, HDL >50 mg/dL, triglycerides <150 mg/dL). 2
- Add statin therapy to lifestyle treatment for all diabetic patients with overt cardiovascular disease 2
- Add statin for patients >40 years with ≥1 cardiovascular risk factor even without established disease 2
- Primary LDL goal: <100 mg/dL in individuals without overt cardiovascular disease 2
- Optional intensive goal: LDL <70 mg/dL using high-dose statin in established cardiovascular disease 2
- If LDL targets not achieved on maximal tolerated statin, aim for 30-40% reduction from baseline 2
- Reduce saturated fat, trans fat, and cholesterol; increase omega-3 fatty acids, viscous fiber, and plant sterols/stanols 2
Antiplatelet Therapy
- Aspirin 75-162 mg/day for secondary prevention in diabetic patients with cardiovascular disease history 2
- Clopidogrel 75 mg/day for documented aspirin allergy with cardiovascular disease 2
- Continue β-blockers for at least 2 years after myocardial infarction; longer-term use reasonable if well tolerated 2
Immunizations
- Annual influenza vaccine for all diabetic patients aged ≥6 months 2
- Pneumococcal polysaccharide vaccine for all diabetic patients aged ≥2 years; one-time revaccination for those <64 years previously immunized before age 65 if >5 years elapsed 2
- Follow CDC recommendations for hepatitis B vaccination 2
Lifestyle Modifications (All Patients)
Lifestyle intervention is foundational for both prediabetes and diabetes management: 2, 3
- ≥150 minutes per week of moderate-intensity aerobic activity (≈700 kcal/week), spread over at least 3 days with no more than 2 consecutive days without activity 2
- Add resistance training at least twice per week 2
- Mediterranean or DASH dietary pattern emphasizing whole grains, legumes, nuts, fruits, vegetables, minimal processed foods 2
- Break up prolonged sedentary periods to lower post-prandial glucose 2
- Eliminate sugar-sweetened beverages entirely 2
- Sodium intake <2,300 mg/day 2
- Weight loss of 5-7% reduces progression from prediabetes to diabetes by 58%, with benefits persisting for cardiovascular disease and mortality reduction at 23-30 years 3
Prediabetes Management
For individuals with prediabetes (HbA1c 5.7-6.4%, fasting glucose 100-125 mg/dL, or 2-hour OGTT 140-199 mg/dL): 1, 2
- Prescribe lifestyle intervention as first-line (details above) 2
- Consider metformin for high-risk individuals: BMI ≥35 kg/m² or age <60 years with prediabetes 2
- Metformin has the strongest evidence base and long-term safety for diabetes prevention 2
- Conduct annual diabetes screening (fasting glucose or HbA1c) because roughly 10% progress to diabetes each year 2
Cost-Related Barriers
Systematically assess financial barriers for all patients and use lower-cost medications (metformin, sulfonylureas, thiazolidinediones) when clinically appropriate. 3
Emphasize collaborative care involving the diabetes care team and social-services professionals to improve access to evidence-based treatments. 3
Common Pitfalls to Avoid
- Do NOT rely on random capillary blood glucose for screening; it is less standardized despite reasonable sensitivity 2, 4
- Do NOT use HbA1c alone in hemoglobinopathies or conditions affecting red-cell turnover; confirm with plasma glucose 2, 4
- Do NOT conduct community-based screening; all screening should occur within a healthcare office visit 4
- Do NOT assume tight glycemic control reduces macrovascular complications; current studies have not demonstrated such benefit 2
- Do NOT stop all diabetes medications in dying patients with type 1 diabetes; maintain small basal insulin dose to avert acute hyperglycemic complications 2