With news that the Tandem T:Slim X2 Control:IQ pivotal study results have been published, I thought it would be worth comparing the data to that from the 670G.
There are some subtle differences in the way the studies were conducted, and therefore, the data that’s available for comparison.
Put briefly, the results suggest that Control:IQ produces very similar outcomes to the 670G.
Tandem with Control:IQ
First up, a few of the takeaways from the 26-week study for Control:IQ were:
- 71% (+/- 12%) Time in Range (70-180mg/dl) for the study compared to 59% (+/-14%) for the control group
- Average Hba1C after closed loop use was 7.06%, which was a reduction of 0.33 percentage points (control adjusted)
- Average glucose level was 156mg/dl (+/-19)
- The system was in use for 90% of the study period
The breakdown and images from the report can be seen below:
What stands out about the pre-study data is that the mean Hba1C is substantially lower than the US median, suggesting that those participating in the trial were more actively engaged in their diabetes management before getting involved. The trial team recognised this in the results paper.
What stands out particularly is the overnight Time in Range that is attributed to the more aggressive overnight target that Control:IQ is able to deploy.
The second image shows a clear reduction in time in hypoglycaemia, which was an important secondary outcome.
So the results aren’t bad. But how do they compare to those from the Medtronic 670G Pivotal Trial?
You have to dig back through the archives a bit to find data about the 670 trial as it’s been that long since the first APS came onto the market. Fortunately, diaTribe helpfully summarised them here.
The key points were for this three month study were:
A 0.5% reduction in A1c, bringing patients from a low initial A1c of 7.4% to 6.9%;
- Time-in-range (71-180 mg/dl) improved from 67% during the two-week run-in to 72% during the study
A 44% reduction in time spent with low blood glucose (under 70 mg/dl);
A 40% decline in time spent in dangerous hypoglycemia (under 50 mg/dl);
An 11% decline in time spent over 180 mg/dl and an 8% improvement in time-in-range (71-180 mg/dl).
- The system was in use for 87% of the study period
It’s worth noting that there was no control group in this study, and that the study period was three months instead of six months.
What do we make of this?
There are a few things that stand out. Probably the biggest is the similarity in outcomes of the two systems.
Both resulted in similar average Hba1C reductions. Both had similar time in range outcomes. The T:Slim seems to have managed better on reducing time spent hypo and in severe hypo.
Another item of note is that the run in period for each of the two systems appears to be different, in that someone going on to the Medtronic system has a two week period in which the system learns about them, whereas Control:IQ had a two to eight week baselining period where it appears that settings were set up for the pump, and then a period of training on the system itself.
The results seem to suggest that Control:IQ being dropped onto the underlying pump settings worked very effectively, however, given the population that was involved in the study; 70% of the patients were using a continuous glucose monitor and 79% were using an insulin pump at the time of enrollment; it’s likely that they were a) engaged and b) starting from a reasonably well set-up point.
It would be interesting to see how intensively those not using a pump prior to enrollment were coached to get their settings correct in the baseline period.
And the takeaway is?
Very simply, Control:IQ is no better, but importantly, no worse than the 670G (or Diabeloop’s DBGL1) when it comes to clinical outcomes. So don’t expect to change systems and get substantially different results.
The key difference? A nicer package in the T:Slim X2, Tandem’s legendary usability and CGM that doesn’t require calibration and constant attention. And an update process that allows for you not to have to change pump system as future iterations come out.
On that basis alone, I’d expect more people to choose this over the 670G.