The annual diabetes review: screening, monitoring and managing complications

Diabetes complications: prevention and early detection are key

Diabetes is associated with a range of complications that are a major cause of disability, morbidity and mortality, including vision loss, lower-limb amputation, renal and cardiovascular disease.¹ With the prevalence of type 2 diabetes in New Zealand predicted to increase by 70 – 90% in the next 20 years, the burden of diabetes complications on patients and the healthcare system will also increase.² Ensuring patients are regularly reviewed is essential to preventing or delaying the onset of diabetes complications and slowing their progression.

Types of diabetes complications

The main complications of diabetes are classified as microvascular or macrovascular complications.

Microvascular complications of diabetes include:³

• Retinopathy
• Nephropathy
• Neuropathy – peripheral and autonomic (e.g. erectile dysfunction)

Macrovascular complications of diabetes include:³

• Cardiovascular disease (CVD)
• Cerebrovascular disease
• Peripheral vascular disease

Other conditions that are commonly associated with diabetes include:³

• Increased risk of infection, e.g. skin, recurrent genitourinary infection, fungal infection
• Dermatological, e.g. diabetic dermopathy, acanthosis nigricans, psoriasis
• Dental and periodontal disease
• Gout
• Polycystic ovary syndrome
• Mental illness, e.g. depression, dementia and disordered eating
• Musculoskeletal, e.g. frozen shoulder, carpal tunnel, Dupuytren’s contractures
• Gastrointestinal, e.g. non-alcoholic fatty liver disease, diarrhoea or constipation (due to diabetic autonomic neuropathy)⁴
• Solid cancers, e.g. breast, bowel, lung, pancreatic, ovarian

Risk factors for diabetes complications

All people with type 2 diabetes are at risk of long-term complications. Factors that increase this include:³

• Early onset diabetes
• Older age
• Māori or Pacific ethnicity; any non-European ethnicity
• Low socioeconomic status
• Long duration of diabetes
• Poor glycaemic control
• Pre-existing complications or co-morbidities, e.g. established CVD, microalbuminura and/or reduced estimated glomerular filtration rate (eGFR), hypertension, dyslipidaemia, obesity
• Smoking
• Reduced engagement with health services
• Poor adherence to treatment

The basic components of an annual diabetes review

The following list describes the basic components of an annual diabetes review. In practice, these may be reviewed at different times, but all should be performed at least once per year.³ More frequent review may be indicated depending on the patient’s risk factors.

N.B. An annual review is a quality standard of care for all people with type 2 diabetes in New Zealand.⁵

• Measure:
  • Weight and waist circumference^*
  • Blood pressure
• Examine:
  • Neurovascular examination of the feet (also include skin, nails, deformity)
  • Teeth and gums
• Request:
  • HbA_1c
  • Urinary albumin:creatinine ratio
  • Serum creatinine
  • Liver function tests
  • Non-fasting lipid studies
• Review:
  • Ensure retinal photoscreening is up to date (every two years)
  • Cardiovascular symptoms (e.g. chest pain) and risk – using a validated CVD risk calculator (see below)
  • Smoking status
  • Alcohol intake and recreational drug use
  • Mental health – see: “Stay vigilant for diabetes burnout and distress”
  • Contraception – pregnancy planning is recommended for women with known diabetes who wish to conceive, e.g. ensure glycaemic control is optimal and the medicine regimen is appropriate while pregnant and breastfeeding
  • Influenza, pneumococcal and COVID-19 immunisation status – people with diabetes are eligible for funded annual influenza vaccination and early access to COVID-19 vaccination; pneumococcal vaccination is recommended, but not funded. See the Immunisation Handbook 2020 for further information: https://www.health.govt.nz/our-work/immunisation-handbook-2020
  • Ensure cervical, breast and bowel cancer screening up to date
  • Any other associated complications, e.g. sexual dysfunction, recurrent skin or genitourinary infection

^*Although waist circumference measurement is recommended in guidelines, in practice this may be of limited usefulness and is therefore not essential

The recommended CVD risk calculator for people with type 2 diabetes is available from the New Zealand Society for the Study of Diabetes: www.nzssd.org.nz/calculators/calculator/1/cvd-risk-assessment

Further information on managing diabetes in pregnancy is available in the New Zealand Society for the Study of Diabetes type 2 diabetes management guidance, available from: https://t2dm.nzssd.org.nz/Section-99-Diabetes-in-pregnancy

Managing type 2 diabetes complications

Lifestyle interventions (i.e. exercise and dietary management for weight loss, smoking cessation, reducing alcohol intake) and optimisation of glycaemic control, blood pressure and lipid levels are the cornerstones of managing CVD risk and preventing or delaying microvascular complications. Pharmacological treatment is often indicated, depending on the patient’s risk factors and individualised treatment targets.

For further information on optimising glycaemic targets in older people, see: bpac.org.nz/2019/diabetes-elderly.aspx

For further information on weight loss for people with type 2 diabetes, see: “Weight loss for the prevention and treatment of type 2 diabetes”

Managing CVD risk in people with type 2 diabetes

Hypertension

Individualised blood pressure targets are recommended for people with hypertension and type 2 diabetes (Table 1). Less stringent targets may be indicated for patients at higher risk from hypotension, e.g. older people, diabetic autonomic neuropathy.³

A CVD risk calculator validated for use in people with type 2 diabetes is available here: www.nzssd.org.nz/calculators/calculator/1/cvd-risk-assessment

N.B. CVD risk calculators may underestimate risk in younger patients or those with a strong family history.³

Pharmacological treatment choice is guided by the presence of diabetic kidney disease

The type of pharmacological treatment for patients with type 2 diabetes and hypertension is determined by whether they have diabetic kidney disease (DKD):³

• If DKD present: Initiate an angiotensin-converting enzyme (ACE) inhibitor or angiotensin II receptor blocker (ARB)
• If DKD absent: Initiate an ACE inhibitor, ARB, calcium channel blocker or thiazide diuretic first-line; an ACE inhibitor is recommended first-line for patients with heart failure⁶

Multiple antihypertensives are often required to achieve a blood pressure < 130/80 mmHg and there should be a low threshold for initiation of a second antihypertensive, e.g. a calcium channel blocker.³

For further information on selecting an antihypertensive, see: bpac.org.nz/2021/ace.aspx

For further information on managing DKD, see: bpac.org.nz/2019/renal.aspx

Table 1. Blood pressure targets for people with type 2 diabetes and hypertension³

Dyslipidaemia

The decision to initiate a statin in people with type 2 diabetes is determined by the patient’s CVD risk and whether they have established macrovascular or renal complications (Table 2).³ A target LDL cholesterol of < 1.8 mmol/L is recommended for patients with CVD risk > 15% or a TC/HDL-C ratio ≥ 8, with treatment titrated based on non-fasting lipid studies every three to six months until the target is reached.³ Patients who have a five-year CVD risk > 15% and LDL cholesterol > 2 mmol/L despite taking the maximum tolerated dose and potency of statin should have ezetimibe added to their regimen (Special Authority approval required).³

For further information on prescribing statins, see: bpac.org.nz/2021/statins.aspx

Table 2. Blood pressure targets for people with type 2 diabetes and hypertension³

Consider antiplatelet treatment for patients with high CVD risk

Aspirin, 100 mg daily, is recommended for secondary prevention in all patients with type 2 diabetes; clopidogrel can be used if aspirin is not tolerated.³ Consider aspirin for primary prevention for patients with five-year CVD risk > 15% AND a low risk of bleeding.³ People with diabetes have a small increased risk of bleeding⁷; this risk may outweigh the benefits of treatment for primary prevention in patients with lower CVD risk.³

For further information on prescribing aspirin for CVD risk management, see:bpac.org.nz/2018/aspirin.aspx

Managing microvascular complications

Diabetic retinopathy

Diabetic retinopathy is a common microvascular complication of diabetes; there are two main types:⁸

• Non-proliferative retinopathy– characterised by increasing numbers of microaneurysms; at moderate to severe stages, vascular permeability increases, which can lead to macular oedema
• Proliferative retinopathy – characterised by the growth of new blood vessels on the retina and posterior surface of the vitreous; formation of scar tissue can cause the retina to detach, leading to permanent vision loss

Diabetes can also increase the risk of other eye conditions, such as cataracts.³ The main risk factors for diabetic retinopathy are the duration of diabetes (i.e. the longer the duration the greater the risk) and poor glycaemic control; other risk factors include nephropathy, hypertension, dyslipidaemia and smoking.⁴

Key points for preventing or slowing the progression of diabetic retinopathy:^{3, 4, 8}

• Refer all newly diagnosed patients with type 2 diabetes for retinal photoscreening; screening should be repeated at least every two years
• All pregnant women with diabetes prior to pregnancy should undergo additional photoscreening in the first trimester; women who develop gestational diabetes do not require photoscreening
• Ensure that glycaemic control and management of hypertension and dyslipidaemia are optimised
• In patients with macular oedema, stop pioglitazone as this can exacerbate the condition by increasing fluid retention. New Zealand guidelines recommended considering initiation of a fibrate (e.g. bezafibrate [unapproved indication]).³ There is some evidence that fibrate treatment slows the progression of diabetic retinopathy.⁹
• Urgently refer patients with rapid vision deterioration for ophthalmology assessment

For further information on diabetic retinopathy, see: bpac.org.nz/bpj/2010/august/retinopathy.aspx

Diabetic kidney disease (DKD)

Key points for managing patients with DKD:³

• Initiate an ACE inhibitor or ARB in patients with microalbuminuria (two or more urinary albumin:creatinine ratios (ACRs) in > 3 months of > 2.5 mg/mmol in males and > 3.5 mg/mmol in females) or a decline in eGFR:
  • Repeat the measurement of serum creatinine and potassium 7 – 10 days after initiating an ACE inhibitor or ARB. If eGFR decreases by > 25% or potassium > 6 mmol/L, reduce or stop the ACE inhibitor or ARB.
• Consider adding spironolactone for patients with macroalbuminuria (urinary ACR > 30 mg/mmol) and hypertension, but also consider the risk of hyperkalaemia and further decline in eGFR
• Strongly consider initiating empagliflozin, a sodium glucose co-transporter 2 (SGLT-2) inhibitor, or dulaglutide, a glucagon-like peptide-1 (GLP-1) receptor agonist, as these medicines have direct beneficial effects on the kidney and improve renal outcomes in people with type 2 diabetes (Special Authority approval required)¹⁰
• Strongly consider initiating a statin – recommended regardless of the patient’s CVD risk

Monitor the patient’s serum creatinine, potassium levels and urinary ACR every three to six months.³ Ensure doses of other treatments are adjusted accordingly to any decline in eGFR.³

For further information on managing diabetic kidney disease, see: bpac.org.nz/2019/renal.aspx

For further information on empagliflozin and dulaglutide, see: “New diabetes medicines funded: empagliflozin and dulaglutide”

The “diabetic foot”: managing peripheral diabetic neuropathy and peripheral vascular disease

Key points for managing the diabetic foot in primary care include:^{3, 11}

• Optimise glycaemic control and management of hypertension and dyslipidaemia
• Recommend and support smoking cessation to slow progression of peripheral vascular disease
• Provide advice on basic foot care:
  • How to self-check feet
  • Wearing suitable footwear
  • Nail care
  • Moisturising dry feet – consider prescribing cetomacrogol aqueous cream + glycerol (e.g. Sorbolene)
  • When to seek medical advice
• Treatment options for neuropathic pain include:
  • Analgesics for mild pain, e.g. paracetamol or a NSAID. N.B. Use NSAIDs with caution in people with renal impairment, particularly if taking an ACE inhibitor or ARB.
  • Low-dose tricyclic antidepressant, e.g. nortriptyline, amitriptyline (unapproved indication for both medicines) taken in the evening to assist sleep and minimise daytime somnolence
  • Pregabalin or gabapentin
  • Carbamazepine
  • Topical capsaicin 0.075% for localised pain (subsidised by endorsement)

Refer to the New Zealand Formulary for dosing information on medicines used for neuropathic pain: www.nzf.org.nz/nzf_2556

For further information on managing diabetic peripheral neuropathy, see: bpac.org.nz/bpj/2014/june/diabetic-peripheral-neuropathy.aspx