Navigating diabetes medications

Recommendations on the use of hypoglycaemic medications are getting clearer. Metformin is still first-line. Gliflozins (SGLT2s) and gliptins (GLP1s) improve survival though the latter require injections. DPP4s are safer than sulphonylureas.

This is based on data showing mortality benefit with both SGLT2s and GLP1s, and increasing concern about hypoglycaemia, particularly in the elderly and patients with established vascular disease. Sulphonylureas are the ‘bad guys’ causing both hypoglycaemia and weight gain. DPP4s don’t prevent macrovascular complications, but don’t cause hypos or weight gain.

Dr Andrew Klimaitis, Physician
Dr Andrew Klimaitis, Physician

Good diabetic control slows down microvascular complications so there is still a place for sulphonylureas and Acarbose, even without macrovascular benefits.

Start with Metformin. There is some mortality benefit and possibly slowing-of-ageing properties.

With any suggestion of cardiac disease, especially heart failure, use an SGLT2. Studies show that gliflozins improve cardiac outcomes just as much in non-diabetics. Cardiologists prescribe them without PBS reimbursement. Gliflozins also preserve renal function in most forms of nephropathy. Their effectiveness with a GFR below 30 is less clear, but they seem to continue helping even without further glucose lowering.

GLP1s sell themselves because of appetite suppression and weight loss. Not everyone tolerates them, but it is amazing how prepared patients are to self-inject if they might lose a few kilos. Gliptins reduce vascular complications, particularly strokes. This hasn’t yet been generalised to non-diabetics. Combining a GLP1 (PBS), SGLT2 (around $50 non-PBS), and Metformin maximises weight loss.

DPP4s are the best-tolerated agents, particularly in the elderly, but don’t use them (or GLP1s) in patients with a past history of pancreatic disease.

If the glycated Hb remains above 8% then insulin should be considered. Most type 2s exhibit fasting hyperglycaemia. Toujeo (or Lantus) can be given once daily. Start with the same number of units as the average fasting sugar reading. Increase by two to four units weekly until the fasting sugars drop to single figures, eventually aiming for sixes and sevens. Ryzodeg can be used instead (once daily before biggest meal) if postprandial sugars are also elevated. This incorporates a short acting insulin into the regime.

Twice or three times daily regimes can be used later, but many type 2s are fine with once daily insulin. Dulaglutide (used weekly) is not PBS subsidised with insulin, though exenatide (used twice daily) is. GLP1s can mitigate insulin’s weight gain.

Bariatric surgery should be discussed and can have dramatic benefit. Most patients know someone who’s had the operation. Their enthusiasm will generally reflect how things went for that person.

Lastly, don’t overtreat the frail. A study of frail elderly living in the community, but requiring some form of home assistance, showed that maximal survival was at a HbA1c of 8.5%. Patients at 7.5% did worse, roughly equivalent to those at 9.5%. Tighter control presumably caused more hypos which then translated into falls, strokes, etc.

Key messages

  • Good diabetes control slows microvascular complications
  • Tailor medications to patient circumstances
  • Beware overtreatment in the frail

References available on request.

Questions? Contact the editor.

Author competing interests: None to disclose.

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