Older age is not a barrier to closed-loop therapy, according to Australian research that shows it provides significantly better glucose control than sensor-augmented pump therapy.

A Melbourne study randomised 30 adults over 60 years of age and with long-standing type 1 diabetes (mean 38 years) to sensor-augmented pump therapy for 4 months, followed by closed loop therapy for 4 months, or the opposite sequence.

The study found all prespecified CGM metrics were more favourable during closed loop than sensor-augmented pump use.

“The primary outcome, TIR measured by CGM, was significantly higher in the closed loop stage (75.2% [SD 6.3]) than in the sensor-augmented pump stage (69.0% [9.1]; difference of 6.2 percentage points [95% CI 4.4 to 8.0]; P < 0.0001), a difference that amounted to 90 min/ day,” the study said.

The time with CGM >10.0 mmol/L was 5.4 percentage points lower in the closed loop stage than in the sensor-augmented pump stage (P < 0.0001), with a difference of 78 min/day.

“The time below each hypoglycaemia threshold (3.9, 3.3, and 3.0 mmol/L) was lower during closed loop than sensor-augmented pump; the time <3.9 and <3.0 mmol/L amounted to 7 and 2 min/day, respectively, less with closed loop than sensor-augmented pump.”

The study, published in Diabetes Care, found the differences in CGM metrics between stages were most pronounced overnight.

Glucose variability was significantly lower with closed-loop stage than sensor-augmented pump stage.

As well, the improvements in CGM metrics during closed loop were achieved with no overall change in insulin dose delivered.

Five participants each experienced a severe hypoglycaemia event; three during the closed-loop stage, and two during the sensor-augmented pump stage.

The study found most participants (100% during closed loop and 97% during sensor-augmented pump use) met the recommended CGM-based targets for older adults of >50% TIR and <50% time >10.0 mmol/L.

“However, there were more participants during the closed loop than the sensor-augmented pump stage who met the hypoglycaemia target of <1% time <3.9 mmol/L (13 participants [43%] vs. 7 participants [23%], respectively; P 5 0.031) and the target of <10% time >13.9 mmol/L (29 participants [97%] vs. 22 participants [73%], respectively; P 5 0.016).”

“More participants met all four CGM-based target recommendations for older adults during closed-loop than sensor-augmented pump therapy (13 participants [43%] vs. 3 participants [10%], respectively; P 5 0.0020).”

The investigators, led by Dr Sybil McAuley from St Vincent’s Hospital and the University of Melbourne, said the trial results warranted consideration of even tighter targets in the absence of frailty.

“Consideration of a higher TIR target (even up to the >70% target recommended for the general adult population) therefore warrants exploration for older robust, and possibly even pre-frail, individuals with type 1 diabetes who are in relatively good health.”

“Of clinical relevance, participants’ cognitive and functional status did not deteriorate during the trial with the more intensive closed-loop therapy intervention, although longer-term effects will need further study.”

Dr McAuley told the limbic that it was useful to have the evidence that closed loop therapy works quite convincingly to improve glucose control.

“As a clinician I support having many options… so patients can choose what works for them. The more I can discuss the options and individual circumstances, hopefully that supports each person with diabetes to make a decision about what technology they would like to use or what equipment they wish to wear to manage their diabetes.”

“All this is to use technology to reduce the burden of living with type 1 diabetes.”

She said she may not necessarily suggest changing someone to closed loop therapy if they had been doing well on MDI for years or if they had particular comorbidities or cognitive impairment that could affect their safe use of this technology.

The study used a first generation closed loop system MiniMed 670G which still requires fingerpricks to calibrate the sensor multiple times per day.

“So when sensors progress and are more accurate, reliable, and don’t need calibration, that will make this technology more accessible to more people particularly if there are either physical or cognitive issues limiting people from interacting with the system.”

Dr McAuley noted that limited government funding created a barrier for adults who did not meet criteria and for whom the cost of diabetes technology was prohibitive.