10. Diabetes Mellitus Recommendations

Type 1 diabetes mellitus
All people with Type 1 diabetes should receive professional lifestyle advice. Statins should be offered in type 1 diabetes for the following categories:

  • All patients with type 1 diabetes aged ≥50 years.
  • The majority aged 40–50 years, unless short duration of diabetes (<5 years) and absence of other CVD risk factors.
  • Those aged 30–40 years with any of the following features: long duration of diabetes (20 years) and poor control (HbA1c >9% (75 mmol/mol)), persistent albuminuria (>30 mg/day) or eGFR <60 ml/min, proliferative retinopathy, treated hypertension, current smoking, autonomic neuropathy, total cholesterol (>5 mmol/L) with reduced HDL-cholesterol (<1 mmol/L for males and <1.2 mmol/L for females), or central obesity, or with a family history of premature CVD (<50 years).
  • Those aged 18–30 years should receive statins if persistent albuminuria is detected, with caution exercised in women of child bearing potential.

Blood Pressure

  • This should be maintained at 130/80 mmHg and consideration of lower values (120/75–80 mmHg) as a target in younger type 1 diabetes (aged <40 years) with persistent microalbuminuria.
  • ACE inhibitors should be the drug of first choice.

Aspirin

  • There is no role for aspirin in primary prevention of CVD in type 1 diabetes.

Glycaemic control

  • Intensive glycaemia control aiming to achieve and maintain an HbA1c of 48–58 mmol/L should be considered the ideal approach to long-term care of type 1 diabetes.

Type 2 diabetes mellitus
All people with Type 2 diabetes should receive professional lifestyle advice.
Lipid lowering

  • Statin therapy remains the best and only effective lipid modifying agent to lessen CVD in type 2 diabetes.
  • Statin therapy is recommended for all patients with type 2 diabetes above age 40 irrespective of cholesterol level.
  • Intensive statin is recommended for diabetes patients with existing CVD, and those with persistent proteinuria or CKD with eGFR 30–60 mL/min. Intensive statin treatment is also recommended for patients who do not achieve non-HDL-cholesterol targets.
  • Statins should also considered for patients with type 2 diabetes under 40 years of age if there is evidence of persistent albuminuria, eGFR <60 ml/min, proliferative retinopathy, treated HBP, or autonomic neuropathy.
  • Fibrates, used as monotherapy or in combination therapy, have not been shown to provide overall cardiovascular benefit in type 2 diabetes, and should not be prescribed routinely for CVD risk reduction.
  • Fibrates show promise in prevention or treatment of retinopathy in type 2 diabetes in a manner independent of lipid-lowering action.

Blood pressure

  • Lowering systolic blood pressure (BP) in the majority of type 2 diabetes patients to around 130 mmHg appears beneficial. Pursuing lower targets does not reduce coronary event rates, although stroke incidence may be modified.
  • The actual lowering of BP appears to be the critical aspect in reducing CVD risk rather than the method or agent used to lower BP, although renin–angiotensin system blockade appears to reduce overall mortality as first-line therapy.
  • The ACE inhibitor/ARB class of agents reduces development and progression of albuminuria and reduce major renal outcomes.
  • Dual blockade of the renin–angiotensin system with ACE inhibitors, ARB or direct renin inhibitors in any combination, is associated with worsening cardiorenal outcomes and should not be used.

Glycaemic control

  • The true effect of intensive glucose lowering cannot be conclusively quantified, but available trial results suggest a 10–15% reduction in CVD events for around a 0.9% (10 mmol/mol) reduction in HbA1c.
  • Recent trial findings and observational studies have noted younger onset type 2 diabetes has an especially poor prognosis, requiring earlier intensive glucose lowering and reduction of all CVD risk factors, whereas intensive glucose lowering may not be appropriate in older patients and/or those with existing CVD.
  • The CVD effects of intensive glucose lowering are less than can be achieved with statin therapy or BP-lowering therapy.

Aspirin

  • Low-dose aspirin is not recommended for primary prevention of CVD in patients with type 2 diabetes.